Cirrus Engineering

Tires and Tubes Cont.

2012-01-31T09:49:00.000-06:00

Over the past few years we have received reports of tires going flat. The reports are sporatic with seemingly no common theme. I blogged about it back in this June 2010 post. We have been working with Goodyear to try to understand what might be causing this, and have tried some of their new tires.

More explanation has come from the FAA via a revision to a Special Airworthiness Information Bulletin (SAIB) published today. CE-11-47R1 explains how Goodyear has been working with different compounds to try and eliminate the various tube failures they have seen in cold and warm weather. Cirrus continues to be active in discussions with Goodyear and help in any way we can.

"Orbits" Part 2

2012-01-25T14:58:00.000-06:00

In my previous post I described some of the technical hurdles we encountered during the development and certification of the Garmin GSR56 Iridium Transceiver. The story continues with the new Garmin GMA350 audio panel. We had been evaluating some prototypes of this new audio panel and wanted to put it into production, but we also wanted to be able to offer a GSR56 Iridium transciever retrofit kit for existing users to install in their airplanes that have the existing GMA347 audio panel. This meant we had to test the Iridium system with both the existing GMA347 audio panel and the new GMA350 audio panel.

What this means for us is that we had to install and test this in an airplane twice. The wiring for the two audio panels is completely different which complicates things. We had to take one of our experimental airplanes which has the GMA347 audio panel and install the Iridium box and associated structural modifications, hardware and new antenna. We then did all the testing with that version of the installation. Then we took out the old audio panel, rewired the airplane for the new audio panel and repeated all the testing for that installation.

Software is another area where people tend to think it is an easy change, but we spend a lot of time doing enough testing, in many different conditions and scenarios, to ensure that there are no bugs in the software. This involves not only on-aircraft testing, but also installing it in a "bench" installation in our lab. We can simulate a lot of different warnings and other scenarios on the bench before actually doing the flight testing.

But real world results come from the extensive ground and flight testing we do. Every flight test program ends up with some interesting stories and this project is no different. One interesting bug we discovered was that a phone call would not terminate when you clicked hang-up on the aircraft but the guy on the other end of the phone didn't hang up (like when dialing into your voice mail.) This has since been fixed.

Another instance occurred when we were proofing out the voice service. From the ground we called the test aircraft and the guy talking from the plane then sat through a 45 minute teleconference. What we didn't know was that when we dialed the aircraft from our land line it was being considered an international call by our company phone service which racked up quite a charge. Oops.

So after all this testing we finally got a solution that we were happy with and began the process of creating all the various drawings (wire harnesses, installations, structural changes etc), and summarized all of our testing through plans and their test reports, along with a couple of certification reports and submitted that to the FAA.

While that was going on, we sent an airplane down the production line to act as a "pilot build" aircraft. We use this aircraft to proof out our drawings, any new processes, parts and installations. It also provides a chance to give the factory technicians training if necessary. We then feed back any information we learn to correct drawings or re-orient the line flow prior to the need to build these airplanes at rate.

With all of that complete, and final approval from the FAA we are able to confidently move forward with production knowing that there will be a few minor changes needed but overall production will proceed smoothly.

Child Safety and the NTSB

2012-01-20T16:27:00.001-06:00

We are quite honored that Debbie Hersman, the Chairwoman of the NTSB took note of our new LATCH system installation in the 2012 model rear seats by writing about it in her official blog called the NTSB Safety Compass.

We pride ourselves, and work very hard to make our airplanes as safe as possible, this new rear seat is just another step in our always ongoing process of continous improvement.

http://safetycompass.wordpress.com/2012/01/20/improving-child-safety-on-airplanes-one-seat-at-a-time/

Perspective Global Connect Retrofit

2012-01-18T16:10:00.000-06:00

We have received a lot of inquiries about whether the GSR56 Iridium transceiver will be retrofittable for existing Perspective airplanes and the answer is yes. The engineering team is working on the retrofit kit that would go out to the field. It is not a simple installation as there are structural modifications to the CAPS bulkhead and wiring harness changes, and installations of racks and antennas. These changes are quite different than the changes we make for production.

For example there are things we can do to the bulkhead during the initial lay up of the part like add hard points that cant be as easily done in the field or at least not in the same way. So it requires developing special instructions, and parts to complete the retrofit properly.

My intention is to have that kit available for the field in the first half of 2012.

"Orbits" Parts 1

2012-01-17T08:00:00.001-06:00

One of the biggest requests from our European and other foreign customers is the ability to download satellite weather. We here in the US have been blessed with XM weather but that does not extend beyond our boundaries. Orbits was our internal code name for the project that installs the Garmin GSR56 satellite transceiver that uses the Iridium satellite network and integrates it into the Perspective system. This option is called the Perspective Global Connect by the sales and marketing group. We use code names to make it easier to describe internally, to give some security to the project and it is just fun coming up with names as a project kick-off exercise.

This project took about 9 months to complete, and although on the surface it may seem to be easy (it's just box and some wires right?) or that FAA certification causes a big delay, the truth is, to find a place to put the product, run the wires and test it enough to insure it meets Cirrus standards takes some time.

So the first step for us was to find a place to put the antenna. Anyone who has looked at our airplane lately realizes that there isn't room for any more antennas on the airplane. The antennas need to be spaced apart from one another to ensure they work properly. In this case we identified a combo antenna (with GPS 2) to use, and put it in the same spot as the existing GPS 2 antenna.

Of course we now have to verify the performance of GPS 2 in a bunch of different conditions to ensure there wasn't any interference or performance degradations due to the new antenna. Also since this is transmit/receive based system we have to ensure performance during both modes.

Then we had to find a place to put the actual GSR56 box. The console is full, all the under floor space has long been used up and the shelves in the aft equipment bay are also full. We ended up creating mounting locations on the back side of the CAPS bulkhead. It is accessible through the access hole on the side of the airplane. This required structural changes to the bulkhead and we used a mock-up to ensure we could actually install the bracket and box during production and in the field, and assessing the weight and balance impact.

Having this box in the back of the airplane also meant a long harness connecting it to the Perspective system in the cockpit. So once again, we had to ensure that the long harness didn't create any RF noise issues.

That summarizes the high level design considerations we had to go through. Stay tuned for Part 2 which will describe some of the test articles, the affects of the audio panel, and some funny stories that happened along the way.

New Features

2012-01-16T08:50:00.000-06:00

Last week we announced some new features in the 2012 models. We added an Iridium based satellite transciever which allows our customers outside of the US to download weather to the cockpit and everyone to make phone calls and text messages.

We also updated our rear seat. Making it more comfortable, adding a 3rd seat belt for those who have young kids, and adding LATCH (lower anchors and tethers for children) hardware to allow those with car seats to attach them to the airplane just like their car.

Over the next couple of weeks I will be writing a few blog posts describing the ups and downs of designing and certifying these new features. Until then check out CirrusAircraft.com for more details.

Flap Relay Winter Update

2012-01-10T08:08:00.003-06:00

I just realized that it has been 6 months since I last updated everyone on the flap relay redesign progress. Unfortunately things slowed down quite a bit in the fall. We put together a drawing and requirements package and sent that out to several potential manufacturers. We chose a vendor to build some pre-production parts but then further discussions with them led us to choose a different vendor.

This latest vendor has given us some great suggestions for packaging and design changes to lower the production costs yet make it more robust. So we expect to get 4 pre-production samples in early February for evaluation and to prove out their production methods.

The prototype unit continues to be used in one of the experimental airplanes with no issues. We are now hoping for a late Q1 release of the new flap relays.

SR22T Oil Separator

2012-01-05T14:48:00.000-06:00

I mentioned in an October blog post that one of the biggest reliability issues we were having that was specific to the SR22T was with the oil cooler flange cracking. This is due to the existing oil separator being attached to this flange and applying excessive fatigue loads.

We had identified this area as a good place for a potential redesign at the start of production because it was difficult to access, and had potential chafing issues. With other priorites in Engineering we didn't focus on it for about a year. As fate would have it, it took a year or so before the fatigue cracks grew to the point they were noticable on the flange and we began to get reports from the field. We then put a production fix in place replacing the existing oil separator with an Andair separator which mounts completely differently and also provides more access.

All the parts are now in place to fix the airplanes in the field. SB2X-71-19 provides the necessary instructions to replace the separator and prevent future oil cooler cracking.

Year in Review

2011-12-21T12:16:00.000-06:00

I am just wrapping up my first full year of the Cirrus Enginering Blog and during this reflective time of year I thought it would be fun to go back and review what has happened and where we are going.

From a blog perspective, I have seen my readership double from 2010. Like our airplanes, my blog is viewed in many foreign countries. In fact 45% of my hits are from outside the united states, and 30 different countries in the last 30 days. It is easy to be "US-centric" but being involved with customers and servicing our airplanes I quickly realize how global our company is.

I have been lucky to meet many of my customers either by phone, email, or in person here at the factory, at the COPA migration this past summer in Colorado Springs, or at the Cirrus Partner Symposium. My customers are not only owners, but also service centers, suppliers, mechanics etc. I am fascinated at the broad spectrum of people who not only love aviation but also read my blog.

From a field service perspective, my year has been focused on the "Top 5" which I introduced last December. I provided updates through the year on our progress, showing our successes and our failures along the way. We have taken one of the Top 5 off the list (field control modules), are seeing great improvements in alternator reliability and fluid quantity indication, and are seeing the light at the end of the tunnel for flap relays and oil/manifold pressure sensors.

We had a few service bulletins throughout the year and I tried to explain the process on how we discovered it and how we fixed it. I also shared how the first year with the SR22T went from a design and maintenance perspective. We also celebrated a few milestones. Corporately, we had the 10th anniversary of the SR22, and the 5000th airplane, from a personal side my SR20 partnership and my 1000th flight hour.

It is an exciting time at Cirrus. We strive to continuously improve our processes and our airplanes both with new products and improved reliability for the field. I look forward to 2012 with great anticipation and expectations, sharing our triumphs and our struggles, and continuing to provide you with a glimpse of what goes on in my little corner of the world.

Thanks for reading. Fly safe.

Alternate Air Service Bulletin

2011-12-20T13:08:00.001-06:00

Front view of alt air duct

It recently came to our attention that the hinge pin on the SR22T alternate air door could migrate out. This hinge pin in intended to be retained by deforming the hinge on either end of the pin to a diameter less than the hinge pin. It appears that this was not being done properly by the vendor who assembled this piece.

SB2X-71-20 affects the SR22T fleet and inspects for proper deformation of the hinge to retain the hinge pin, and to create the proper deformation if necessary.

Back view of alt air duct

Interval view of alt air door and hinge

Wing Attach Shim Inspection

2011-12-20T12:25:00.000-06:00

It was discovered that we had inadvertently installed a shim backwards during the assembly of the aft wing attach fitting.

The top picture shows this fitting as seen when the wing root fairing is not installed yet. The second picture shows a close up of the wing-side attachment with the attach plates (white), the shim (grey) and a lightning protection bracket (bronze colored).

This shim has a radius on one side to match up with the radius of the rib. In some cases, the side of the shim without the radius was installed.The bottom picture is an illustration from the Service Bulletin that more clearly shows the correct and incorrect installations.

The service bulletin SB2X-57-12 has you check to ensure that the shim is installed properly, and if not, to reverse it.

Milestone

2011-12-12T11:24:00.001-06:00

All bundled up for the pre-flight inspection

With my round trip flight to Green Bay this past weekend, I passed the 1000 flight hour milestone.

I started taking flying lessons right after I started at Cirrus in early 2000, got my private in August of that year and followed that with instrument, commercial and multi-commercial in the following years. I learned in a Warrior, owned an arrow for many years, and flew company Cirrus airplanes as much as I could. Earlier this year we were fortunate enough to be able to purchase a share of an SR20.

I am very lucky to have a wife who has supported my flying and loves the utility that flying allows us. In fact, our honeymoon was a 14 day air safari in Australia which was an exciting trip for a 100 hour private pilot. Interestingly, on the first day of the air safari while attempting to land at a sheep station, I had to do a go around because of kangaroo on the runway! Although our current flying is a little less "exotic", we now we bring our daughter along to visit her grandparents in other mid-western states, and are planning additional family trips for the future so it remains just as adventurous.

Duluth's lift bridge on one of those magically calm clear days

The past 1000 hours have been an amazing learning experience. They have been filled with beautiful views, good memories, and plenty of tales. I continue to learn something new on nearly every flight, and I hope for continued good health so I can experience another 1000+ hours.

FCM November Update

2011-11-28T09:47:00.001-06:00

Last month I discussed how the new design field control module would be in production the first part of November. That turned out to be true and the new design is now in production. We also did testing of the new field control modules in all the older MCU's and all passed successfully. So the new FCM is now compatible with all versions of the MCU.

This is all great news because it means that the more robust and reliable design can be used to replace failed units in the field.It also means that we should start to see significant reductions in MCU failures caused by the field control module. It will take many months to prove this out with data from the field but for now, I am hopeful that we can take one of the "Top 5" items off the list!

Starter Drive Adapter Service Bulletin

2011-11-23T15:09:00.001-06:00

Cirrusas been notified by Continental Motors Incorporated (CMI) that the havereceived field reports of Starter Drive Adapter (SDA) drive shaft failures thathave resulted in a loss of oil. When thedrive pinion fails, the scavenge oil pump no longer functions resulting in aloss of oil. This affects Cirrus SR22TNand SR22T engines, but field failures have occurred on non-Cirrusinstallations. CMI has developed a new assembly method for the SDA theybelieve will address this failure.

Cirrus has released alert Service Advisory SA11-10 that references CMI Service Bulletin MSB11-4 which calls for the replacement of the starter drive adapter. Effectivity includes all SDA's built in 2011 and used oneither a TAT or SR22T engine. This includes both new production andspares .

CMIis recommending the following for our aircraft:

75hours: flight is not recommended. Aircraft is grounded until starteradapter is replaced.
75-100hrs: starter adapter must be replaced within 10 flight hours.
100hrs: No action is required. Aircraft has made it through the“infant mortality” of its life.

Edited 12/7/11: An emergency AD was issued by the FAA for this issue. AD 2011-25-51 was released November 29th requires compliance with the CMI service bulletin.

Fuel Drain Service Bulletin

2011-11-16T09:00:00.000-06:00

Back in July I wrote about a service advisory for fuel drain sumps. I mentioned that the parts were on order, and would be in stock in November and we would release a service bulletin then to replace those fuel drain sumps.

Well it is now November, and the parts are indeed in stock and we just released SB2X-28-10 which removes and replaces the inboard fuel sumps.

SR22T Chafing SB

2011-11-03T15:03:00.000-05:00

About a year ago, I mentioned in this post that the early SR22T inspections were resulting in great feedback from our service centers. One of the things that they saw was chafing which we partially addressed with SB2X-72-01. One of the areas that was seen early on but not addressed by that bulletin was the appearance of some contact marks on the cowl.

When we first heard of these witness marks on the cowl, we did some experiments using cameras mounted inside the cowl to find out if they were always contacting, or just in certain flight phases. We discovered that not every airplane experienced contact, and it generally only happened at high speed.Any contact was not noticeable to the pilot, you could just see on the inside of the cowl that it had made some contact.

Turbo Oil Reservoir

We made 4 design changes to new production airplanes over the last year to correct this. We added some extra core to the cowl in this area to stiffen it up and prevent it from deflecting as much under the air loads. We also adjusted the trims of the cowl so that it sits a bit lower giving us more clearance. We shifted the turbo airbox up slightly, and adjusted the shape of the turbo oil reservoir to give us more clearance. It is these last 2 items that the most recent service bulletin addresses.

Mandatory service bulletin SB2X-71-18 installs an updated turbo air box, and turbo oil reservoir to the pilot side of the installation. The co-pilot side has not seen any chafing and has a much greater clearance to the cowl.

Carbon vs. Glass

2011-11-01T10:53:00.003-05:00

Last year I discussed how difficult it is to increase the gross weight of the airplane in this post. Of course the other way to increase the useful load of the airplane is to decrease the empty weight. One of the recent suggestions I have been hearing is that we should go to carbon fiber for our structure to get us an extra 200lbs of useful load.

This turned into an interesting thought exercise for me this week. Could we save some weight by going to carbon? The density of carbon is about 30% less than the fiberglass, so the answer of course is yes but not as much as you might think, and definitely not 200lbs..

The design of the Cirrus fiberglass structure is actually quite efficient. The structural weight of the airplane is actually quite low, about the same weight as the engine, and the actual weight of the fiberglass portion of that is even less. Most areas of the airplane are just two plies on the either side of core. two plies is the minimum we can go for damage tolerance reasons. So going to carbon, we couldn't take advantage of its strength or stiffness, as it would still need to be two plies everywhere.

Typical ply layup in fuselage

The one place we did take advantage of the carbon fiber strength and stiffness was in the main wing spar during the G3 program. Because this is a solid laminate part that contains large stack-ups of plies, we were able to use the properties of the carbon fiber to take several plies out of the part, and save a lot of weight. But parts that contain large stack-ups of plies can be counted on one hand.

Carbon also brings with it a host of other design issues and changes. We have to put fiberglass barrier plies between the carbon and any metals to prevent galvanic corrosion which adds more weight back. Fasteners have to go to titanium or A286 stainless (can you say cost increase) for the same galvanic corrosion reasons. The expanded metal mesh that we use for lightning protection is made from aluminum, so we have to change to a copper version (heavier and more expensive) over the carbon fiber again for galvanic corrosion.

New carbon structures would also mean re-testing wings, fuselages, etc for strength, fatigue and damage tolerance which although is a lot of fun (if you are an engineer), it is quite expensive and time consuming.

The manufacturing process doesn't really change, but the inspection process changes drastically. We can visually inspect the fiberglass parts, but the carbon parts require non-destructive evaluation. Ultrasonic inspection is the typical method (and the one we use on the spar), but other methods like thermography are also available. With the size of our structure, it means large inspection fixtures, special equipment for each part, and training for the inspectors, but we also need to coordinate the flaw detection size for each part/equipment with the damage tolerance design and structural testing. This inspection increases cost and processing time on a recurring basis along with the upfront development and testing costs.

Finally there is the cost aspect with carbon fabric costing about 3x the cost of fiberglass. So in an aircraft world, where everything is a compromise, we must balance cost, weight, manufacturability, inspection, repair, damage tolerance, performance etc, and when you do that fiberglass continues to win for the SR series.

Trip to Grand Forks

2011-10-28T09:56:00.000-05:00

For the first time since last November, I had the opportunity to visit our Grand Forks facility. On Tuesday, I flew a designer and a materials and process engineer out to our Grand Forks plant so that we could participate in a station audit. A station audit is something we started earlier this year where about once a month we choose one of the various build stations, gather a team of engineers, planners, quality inspectors, and technicians and observe the build process. We are not necessarily looking for what we are doing wrong, but rather where we can be better.

Completed firewall pre-bond

Examples of things we are looking for are; does the planning match how we actually want to build it, are there drawing/design changes that could make the build easier, are there tooling changes that could make the build or inspection easier. At the end of this we have a list of items to go change or at least investigate, and we follow up on those lists over the following weeks.

This audit was focused on the firewall layup. I am always amazed at how seemingly effortless it is for them to lay up composite parts. I have laid up my share of parts over the years, and I never developed a knack for it. These 2 women laid up the whole firewall in around 2 hours and that included a 30 minute lunch break. It takes definite skill and they had it.

Firewall bonded into a fuselage

Parts in Grand Forks are classified by their layup difficulty into 4 classes. In increasing difficulty they are class A, B, C, and Fuselage. The firewall is considered a class C part mostly because it uses a different fiberglass system and core for the high temperatures the firewall sees in service. This makes it more difficult because they handle differently during the lay up process.

The audit was a success. The technicians offered several good suggestions for tooling and marking improvements, and I once again, left completely blown away by the skill and experience of our Grand Forks team.

FCM Fall update

2011-10-27T10:06:00.001-05:00

When I lasted updated field control modules back in August, we were just finishing up the testing and working through the last of the drawings and hoping to have parts in production in September. Well, as seems to be the case from time to time, one thing led to another and we had some delays in getting this new design into production. Those new parts will now be (for sure) in production starting in the next 2 weeks. We will also begin to purge out any existing inventory of field spares and build up a new inventory of the improved parts.

Right now, these parts are only approved in the MCU 140 installation. We believe that they will also work just fine for previous MCU designs, but until we officially test them in those configurations they will remain restricted to the MCU 140. Thus the 2nd phase of this project will be the evaluation of this design in the other MCU's and I will update you as that begins to happen.

SR22T First Year Reliability

2011-10-18T09:16:00.002-05:00

We delivered our first SR22T in the summer of 2010 and we are closing in on having 230 of them in the field. So with 14 months of field experience how are the SR22T's performing from a reliability standpoint?

One of the measures we use to track reliability is percentage of parts replaced. The table below has the top 10 replaced parts on the SR22T in the past year.

The green colored items listed should be familiar to everyone who regularly reads this blog as those are items in the Top 5 reliability that are common to all the models and we have been working very hard to address this past year.

Items 2, 3 and 6 are kits for service bulletins.Number 2 is the service bulletin that replaces the turbo induction seal. This SB was discussed in this blog post a couple of months back. The turbine inlet temp sensor affected the very early SR22T's (first 30 airplanes) and that service bulletin was discussed in this blog back in September 2010. Finally item 6 is a service bulletin that adjusts flap actuator rigging and is common across all models.

The remaining 3 items (in yellow) are all related. The air oil separator is attached to the oil cooler in the SR22T and this has been causing the oil cooler flange to crack. A production change to a different oil separator that doesn't attach to the oil cooler has been made, and a service bulletin is in work right now. I will have a more detailed blog post about this once we release the service bulletin.

So to sum up, 5 of the top 10 items are common across all models, 4 of which are actively being addressed with my Top 5 initiative. The other 5 items have either been addressed by a service bulletin or will be soon. Overall the reliability of the SR22T has been quite good and we have seen no issues with the engine or exhaust to date. We will continue to attack any issues that come up as we get more field experience.

Alt 2 October Update

2011-10-11T13:40:00.001-05:00

I last updated the progress on Alt 2 at the end of August in this post. I talked with some people at our partner symposium a few weeks ago about alternators. One of the common themes and experiences they had with alternator failures on other airplanes in the past were either vibration or heat related. These were two of the things that were brought up during our initial meeting in January with the vendor.

The first main failure mode is the diode.Diode failures can be commonly caused by heat either due to electrical over voltage/current or external temperatures. The alternator sits inside a shrouded area of the cowl, so one might think that it just gets too hot there. We did temperature testing when we first certified the alternator 3 years ago but hadn't done anything since. To verify that we didn't make any changes that affected the temperature of the alternator we re-did the testing and even covered up some of the air vents over the built-in fan and all temperatures were well within specifications. I wrote about this testing back in March in this blog post.

Electrical testing done at the vendor showed that they could get a diode failure during a high load dump scenario. Based on these tests, the type of diode being used is changing. This is still under evaluation and testing and should be implemented by the end of the year.

The other failure mode is rotor failures. Some point in the rotor wiring breaks, and since it could be vibration related, we both evaluated the design for vibration (flight testing with accelerometers) and also made several design changes over the last couple of years to prevent the rotor wires from breaking. Most recently, new bonding equipment is now on-site at the manufacturer which will help further eliminate any broken rotor wires as a failure mode.

As I mentioned in the August post, there were several design changes that took place towards the end of 2010, and it takes a while to evaluate how those changes are performing in the field. To date, no alternator built in 2011 has failed. This is an extremely positive sign that we are on the right path to fix these problems, and that the changes we are making later this year will only help to further improve the reliability of the alternator.

We continue an intense focus on this issue, and I will continue to update you regularly with our progress.

Turbo Induction SB Revision

2011-10-05T08:39:00.001-05:00

We just released a revision to SB2X-71-17R1 that expands the effectivity range of the service bulletin. I posted details about this service bulletin in a previous blog back in July. A handful of airplanes were modified at the factory prior to the service bulletin release, but may not have had the air box flange welds and slots modified properly. So the updated service bulletin is having those airplanes inspected and modified if necessary.

Circuit Breaker Label Service Bulletin

2011-09-26T16:27:00.000-05:00

We recently released Service Bulletin SB2X-11-04 that corrects a circuit breaker label on some SR20's. The label for the PFD#2 circuit was incorrectly labeled PDF#2.

Oddly enough, my blog editing software highlights PFD#2 as being spelled incorrectly. Not surprising how something like this can happen.

2011-09-19T13:50:00.000-05:00

Next week we will be hosting the 2011 Cirrus Partner Symposium. This annual gathering between Cirrus Aircraft and our partners - Authorized Service Centers, Training Centers, Standardized Instructor Pilots, and Suppliers - is comprised of sessions structured to provide meaningful topics and content applicable to the various businesses involved and also to provide valuable networking opportunities.

At the various seminars we will have initiative and program updates, skills workshops, product reviews, and cross-functional training topics in four different tracks. I will be giving a reliability update and also discussing the field repair process (repairing damaged airplanes) on Tuesday afternoon and again on Wednesday morning.

It is a great opportunity for me to talk with all of our service centers, suppliers and other partners. I look forward to this event each fall. I hope to meet more of my blog readers next week.

SA for Tornado Alley Service Documents

2011-09-09T10:49:00.000-05:00

We recently released Service Advisory SA11-07 which notifies owners of Tornado Alley Turbo service instruction SI11-03 and Service Bulletin SB11-04.

Tornado Alley Turbo Service Instruction SI11-03 instructs owners of Turbonormalized Cirrus Design SR22 airplanes to have the turbocharger support assemblies inspected on a regular basis to ensure that the turbo system support rods and bolts do not wear to a point of failure.

Tornado Alley Turbo Service Bulletin SB11-04 instruct owners of Turbonormalized Cirrus Design SR22 airplanes to have the turbocharger oil supply inlet screens inspected and cleaned on a regular basis to ensure that the turbo system continues to function properly.

Please click on the links provided for more detailed information.

Pressure Sensor August Update

2011-08-27T08:44:00.001-05:00

Mate-n-Lock baffle connectors

It has been a while since I updated this particular problem and that is mostly because the problem is proving fairly complicated and difficult to investigate and solve.After several months of research, we have concluded that there are 2 main causes of the erratic behavior; the connector at the sensor, and the mate-n-lock connector at the baffle.

I have previously discussed the baffle connectors and mentioned that we removed the mate-n-lock connectors on several airplanes at one of our fleets.Since none of the 16 airplanes we modified were having a problem at the time we made the change to remove the connector, and none of those airplanes are having issues today, the test becomes inconclusive. However we believe this is having a positive affect.

Looking at the data for several of these modified airplanes, we discovered that there was indeed some erratic indications that were not noticed by the pilots. That leads us to suspect the connector at the sensor. The connector at the sensor is a pretty robust connector common in these applications. Our data shows that using "stabalant" and other contact cleaner/lubricants may actually hurt the performance of these connectors by causing the need for increased contact pressure.

Pressure sensor with prototype clamping

We are also suspecting that wire security at the sensor connector may be contributing to the erratic indications due to excessive wire vibration. We have recently modified a couple of SR20's to clamp the wires close to the connector to reduce that.The problem with this is that each of the 6 sensors (oil and mainfold pressure times 3 models of airplanes) has a different installation and challenges in finding adequate methods of securing the wires.

Pressure Sensor Locations

So to summarize, we are continuing to look at wire security at the sensor, removing the mate-n-lock connectors from the baffle, exploring alternate connectors, vibration table and on-aircraft service testing of all solutions.

Alt 2 August Update

2011-08-26T08:11:00.001-05:00

I felt I should recap where we came from and where we are going in regards to Alternator #2 reliability. This alternator was first introduced on the Cirrus when we introduced Perspective. It was the only alternator that fits in the design space available (belt driven, small size, right mounting style, light weight, and produces enough amps) and it was also a new design with little field experience.

Over the last few years, working with the vendor, we have been able to make a few changes to improve reliability, but it hasn't been good enough. This January we held an on-site meeting to discuss what we knew and what we needed to learn. The vendor continues to tear down every failed alternator and we hold bi-weekly meetings with them to discuss results and next steps.

We have determined that there are now 2 main failure modes, either a rotor failure or a diode failure. A few improvements were made to the rotor assembly at the end of last year, and a new manufacturing technique and equipment will go online next month.

The diode failures still don't have a root cause. We continue to investigate whether it is a mechanical or electrical failure of the diode. We are changing the type of diode we use in the alternator, and that will happen later this year after we thoroughly test the new diodes. We are also evaluating stress and transient response of the diodes using our existing (and new) field control modules to try and replicate the actual airplane condition.

It is still too early to tell how the changes made late last year are affecting the reliability, but we continue to test and work to eliminate the failure modes we have been seeing.

Landing Light Service Bulletin

2011-08-25T08:07:00.000-05:00

We have had a few variations of HID landing lights over the years. Recently it came to our attention that one of the original landing light ballasts is no longer produced. Although it is not common to have to replace a ballast, we still needed some way to update those airplanes to the current ballast.

As typically happens, the current ballast has both a different mounting footprint and completely different connectors. So we recently released a Service Bulletin to provide a kit of parts that has a mounting plate adapter, and custom harnesses to allow the current parts to be installed on older airplanes.

In coordination with this change, we are also working on an IPC update to separate out the bulb specifically since that is the part that normally fails. This way you can just replace the bulb and not have to replace assemblies.

Fluid Quantity Update

2011-08-19T12:53:00.001-05:00

As I announced back in April we have been waiting for supply to build up on the new in-wing fuel dials. We not only had to get stock made for new production, but also to build up a supply for the field. There are a limited number that the company can manufacture in a given week, so it has taken many months to build up that supply.

We are now at the point where these new parts are in production for all models, and the new parts should be available for the field shortly (if not already).The ice protection version of these parts has been in production since December and available for the field as well. So far these new dials have been performing very well, and we have only seen a couple of failures.

However, during this waiting time, we have continued to test airplanes with these new fuel parts and have unfortunately started to see some breakdown in the new parts as well. We have the new parts installed on 2 different airplanes.One has over 150 hours with no degradation, but the other now has over 250 hours and began to show some intermittent degradation starting at about 148 hours. The graphs below show the beginning of the erratic behavior with the result on one flight of fluctuations between empty and full.

What becomes frustrating about this is that it is intermittent.. It doesn't occur all the time, nor on every flight. Below you will see the data for the next couple of flights, and it shows the rock steady indication that we had seen for the first 150+ hours, and continue to see since.

With all this in mind, we must remember that with this technology, these fuel dials are considered a wear item. There are two pieces rubbing together and they will eventually wear. Our bench and on-aircraft testing has showed that these parts are FAR better than what exists in the airplane today with a MTBF probably 2-3x better maybe more, but they are not good enough.

So with that in mind, we began looking into alternate technologies, and a different source for parts last fall. We have installed a prototype version of one technology on an airplane and have done a bunch of bench testing as well, and these new parts look promising. As we get further along in the testing I will report those results and our future work in this department.Further long-term bench testing an on-aircraft testing will be required to ensure that these parts exceed our expectations for reliability.

Great Migration

2011-08-17T13:20:00.000-05:00

I returned from Colorado Springs on Sunday with a nice tailwind the whole way, and beautiful weather. I had a great time at the Migration. The weather and location were great and I was able to meet many blog readers, and perhaps introduced myself to a few new ones.

I gave a talk on Saturday afternoon about reliability that was well attended and informative (I hope). I will be posting a few of the reliability updates on my blog over the next few days. I got a lot of good questions both during my talk and in the many private conversations I had with owners, service centers and sales people.

Next year the COPA migration returns to Duluth and I hope to see many of you there.

Colorado Springs Bound

2011-08-08T08:39:00.000-05:00

I have been asked to speak at the annual Cirrus Owners and Pilots Association (COPA) Migration this year. I will be speaking on Saturday afternoon and my topic will be Top 5 Tech/SDR. I will be discussing in detail how we determined the top 5 issues I have been discussing on my blog for the last 8 months, and give updates on those and other issues as well.

I will be flying an SR20 out there (not my own) on Thursday to be used for a static display during Friday's "Airport Day." Riding with me will be one of my coworkers, Nick, who will be presenting a history of the Cirrus electrical system on Saturday after me.

I hope to meet some of my blog readers while I am out there, as I am sure I will be attending most of the events and hanging around the Cirrus booth on Friday as well. See you there!

August FCM Update

2011-08-01T14:38:00.000-05:00

As I mentioned last month, we had received the first pre-production units and were awaiting aircraft availability to run them through a battery of tests. Those tests were completed in mid-July. They included max load, min load, regulation %, transient load response and stability, load dump etc. Tests were done with batteries on/off and alternators on/off.

The initial engineering prototypes were removed from the airplane with 132 hours on one part and 71 hours on the other and were replaced with the pre-production samples.The last of the drawings are approved this week, and we are hoping for production parts in early September.

SR22T Induction System Service Bulletin

2011-07-26T11:16:00.000-05:00

Late last week, we released a service bulletin that replaces the seal between the induction air box and the turbo on the SR22T installations. SB2X-71-17 removes the Buna N sheet seal and replaces it with a Silicon tube seal. It also adds explicit instructions for bonding this new seal to the turbo with RTV.


Original Seal and Installed Condition

New Silicon Seal

Fuel Drain Service Advisory

2011-07-21T15:54:00.000-05:00

We recently released Service Advisory SA11-06 to alert recent airplane owners of a potential condition where the collector tank drain valve could end up in a position where fuel slowly leaks. These drain valves were installed when a lead time for the existing valve changed drastically and we had to find a substitute. These specific drain valves have lightning protection features which makes it a bit more unique.

The drain valve should behave like the others on the airplane where you push in to sump, however it was discovered that it requires a slight twist and then push to sump fuel. This is accomplished with a special sump cup with beveled edges on the stem to interface with the hex-head of the drain valve.

So although the twist and push to sump is a nuisance, the problem comes in that there is a feature that allows the easy change of the o-ring which requires only a slightly more rotation. When in this o-ring maintenance position it leaks slowly.

Thus during preflight fuel sampling, a scenario could occur where the valve is inadvertently rotated to the servicing position but the valve stem does not actually drop below the valve body due to a combination of low spring forces inherent to the valve design, O-ring wear, and possible fuel sediment. In this state, the drain valve would appear to be closed and no fuel leaks would be apparent. However, after engine start and subsequent vibration, the valve stem could drop into the servicing position and eventually cause the engine to stop running due to fuel starvation.

Once we discovered the nuisance issue and possible pre-flight fuel sampling scenario mentioned above, we worked with this new vendor to design us a valve that didn't require the twist to sump and that is now in production. A Service Bulletin is ready and will be released when we have parts to support the replacement of these fuel drains in the field which should be in a few weeks. This Service Advisory and subsequent Service Bulletin affect the following aircraft only.

Cirrus Design SR20 serial numbers 2077 thru 2085, 2088 thru 2097.
Cirrus Design SR22 serial numbers 3736 thru 3772.
Cirrus Design SR22T serial numbers 0091 thru 0191.

First Trip in "New to Me" Airplane

2011-07-19T10:54:00.000-05:00

Back in April I posed the question about upgrading airplanes from a 1967 Piper Arrow to a 2002 SR20. Well I went through with it, and got all the paperwork completed at the end of June. I am now a 1/4 share owner of a 2002 SR20-1266. This weekend was the first trip for me and my family in the airplane as we flew from Superior WI to Toledo Ohio and back.

8.9 hours of flying gave me lots of time to explore the airplane and the systems. No built-in weather system in this airplane, as it was produced before XM weather was even available, so I continue to use my hand-held version to avoid thunderstorms. We had to stop for 1.5 hours on the way home to allow some thunderstorms to pass, but that stop also gave me an opportunity to shoot my first ILS approach in the airplane.

The avionics in this version are closer to my old Piper than the Perspective airplanes we produce today, but the added redundancy (dual vacuum and electric back-up), large screen MFD, parachute, and the many other built-in safety features make this a much better choice. It is easy to see why this airplane remains so popular.

The comfort factor cannot be ignored either. Getting out of the Cirrus after 3:45 of flying and feeling refreshed is a big change from what we were used to. The extra leg room in the back was also appreciated by my nearly 5 year old daughter, and I am sure she will appreciate it even more as she grows older (and bigger).

We are glad we made the switch to the Cirrus despite the added drive time to another airport and we look forward to many more trips in the future. Now does anyone know of someone in the Duluth area that wants to buy a 1/5 share in a 1967 Piper Arrow?

Flap Relay June Update

2011-07-08T08:10:00.001-05:00

The prototype board continues to function perfectly in the test airplane so we will continue to evaluate that. In addition, with the help of an Engineering Intern, we were able to fabricate 2 more prototypes that we put through some various electrical and environmental testing, all of which were also successful. We did some thorough analysis of the system for things like short circuits and made a few design changes for the production version as a result of that.

Flap motor with prototype relay board installed. Existing relays on table to the right.

Last month I also mentioned the beginnings of the packaging concept phase. That is now nearly complete, we have had an internal design review, and we will be sending it out to our vendors for their input as well.Once we have some feedback from the vendors, we will then start the drawing change process and hopefully have this ready for production later in the fall.

FCM June Update

2011-07-07T07:54:00.002-05:00

Unfortunately delays at the vendor and with our experimental airplane fleet have put us back about a month. The last remaining hurdle is to do an on-aircraft comprehensive electrical test of the field control module. We have parts in hand now, but our experimental airplanes are busy with other tests. We hope to get the testing done next week some time.

In parallel, we have been working on all the drawings, and those are 90% complete. So once the testing is done, the drawing package will be ready to go. Also the vendor has been taking advantage of this change to review their processes and procedures and thus we are making some changes to the testing specification to better account for their process flow and to make things more efficient for them to manufacture the parts.

We are getting close to closing out this project.

Alt 2 Reliability Update

2011-07-06T07:52:00.000-05:00

The past month has continued to focus on the diodes. The detailed failure analysis of the diodes was inconclusive as to a root cause. Bench testing at the vendor was recently able to repeatably drive a failure in the diodes which is a first step in helping us understand what might be causing the problems. As mentioned last month, we are going to be changing the type of diode used in the alternator, and this bench test failure will provide a method for us to verify how well the new diodes will work.We hope that in the next month our vendor will have a new diode set for bench testing.

Maintenance Manual Updates

2011-06-30T12:32:00.000-05:00

Along with the release of POH, IPC and wiring manual updates, we also updated the maintenance manual.There are change summaries that describe all the updates section by section, but one of the main highlights I wanted to point out was the update and reformating of Chapter 5, Time Limits and Maintenance Checks.

Over the last several years we have received many comments from various maintenance organizations such as our own factory service center, the authorized service center network and our fleet operators. Some of the main complaints were that the inspections were too labor intensive, higher than necessary inspection intervals and a poor format in the AMM. Based on this feedback, we created an internal group to make changes to the Scheduled Maintenance Programs.

A newly released Service Advisory explains in a bit more detail about these updated publications and we hope that this new user-friendly inspection schedule and format will better reflect the real-world requirements and the experience of our service network.

As always, we encourage feedback about our publications and you can use this online form to submit your comments and suggestions.http://servicecenters.cirrusdesign.com/TechPubs/serviceloopform.asp

SR20 Oleo Pressures

2011-06-21T08:16:00.001-05:00


Oleo prior to gear attachment

When we added the oleo nose landing gear to the SR20 last year, early reports from our Production Flight Test Pilots said that the taxiing "ride" was a bit "stiff" and was not as good as the SR22/22T. It appeared that with the lower gross weight of the SR20, the pressures set in the oleo (for the SR22/22T) were too high.

So we went through some nose landing gear drop tests at various pressures to prove that the loads didn't go up significantly, and we also tested the ground handling with various pressures as well.After all this testing, we determined a new pressure for the oleo that kept the loads within limits and provided a similar ride for the SR20 that we had with the SR22/22T.

This new pressure of 270 +/- 10psi is found in chapter 12-10 of the updated SR20 Aircraft Maintenance Manual (AMM) that was just released.

Flap Relay May Update

2011-06-02T09:04:00.000-05:00

Last month, I showed a picture of our prototype board that was being fabricated. That board has been completed, and is installed in one of our experimental airplanes after undergoing some bench testing first. Since this prototype board is much larger than the flap relays it replaced, the prototype installation required some additional temporary support as seen in the picture below.

So as this prototype builds time in our experimental airplane, 2 other prototypes are being fabricated to be used for some other environmental bench tests. We are also working with a couple of vendors on some various board fabrication designs to find something that will fit in nearly the same space that the original relay used.

We get a size reduction benefit when we surface mount the production version, and then by splitting the board we can get a further reduced size that we can fit into a box. Final designs wont be done for a couple of months but we are beginning to work on it while our prototype units complete their testing.

FCM May Update

2011-06-01T09:00:00.001-05:00

Pre-production (Left), Prototype version (Right)

We received the first 6 pre-production units from the vendor and put them through a basic visual and electrical bench test before sending them back to the vendor last week for final potting. When that is complete, we will get them back and run through a comprehensive on-aircraft test matrix like we did with the prototypes to ensure there are no surprises.We expect to be doing that testing in the next couple of weeks.

While this is going on, we are making all the drawing changes associated with putting this new product into production. If all goes well we should have all those drawings completed by the end of June, with production starting in July.

Alt 2 May Update

2011-05-31T12:53:00.000-05:00

This month's alternator #2 reliability update continues to focus on the diodes. The detailed failure analysis has not yet been completed by the diode manufacturer so we wait for more root cause information. We did discover that the alternator uses a type of diode that we did not expect, and we are looking into changing the type. It is not believed that this diode type has any affect the reliability, but for consistency with our other alternator applications, we are going to have it changed. We continue to remain very focused on this part's reliability with regular emails and scheduled conference calls.

Transponder Headset Noise cont.

2011-05-23T15:49:00.000-05:00

To further explore possible solutions to the transponder/headset noise problem first discussed in this post, we installed a generous ground plane to the transponder antenna on the outside of the aircraft as an experiment to see if there was any point on trying to develop a compromise version inside the aircraft for production.

Ground Plane Test Setup

Extending the ground plane does two things to help. First, it acts as a shield to protect the headsets from the most direct path of interference, the antenna element itself, and secondly by extending the size of the ground plane, the field at the edge is weaker, compared to a small ground plane, and therefore the eventual exposure around the edge is lower.

The experiment was successful. We learned what we wanted to know, but it did not support the solution we anticipated. We demonstrated that even this uncompromising construct was not effective enough to totally eliminate the headset interference and therefore we don’t need to consider trying to fit-in an ambitious yet compromised version of the ground plane amongst the structures and equipment in the aft part of the aircraft. While improving the ground plane inside might help a little we know now that it certainly wouldn’t cure the problem.

Further work was then started to characterize and quantify the field strengths, using the spectrum analyzer and a blade style antenna, in and around the aircraft and correlating the transponder signatures with the sound heard on the headsets. It was determined that the transponder signal can be heard on the headset from a distance of 40 ft using the battery-powered Bose ANR headset on hand. There seems to be a high degree of reflections of the signal and you can’t hide from it. Unfortunately then it seems there is no place far enough away on the aircraft to be certain there would be no headset interference.

So as originally thought, the best near term solution is headset choice (Bose A20, Lightspeed Zulu, or a non-ANR version). Long term solutions still remain to move the antenna a bit further aft but as these tests showed, that likely wont have a significant affect.

Tornado Alley Turbo Service Instruction

2011-05-18T15:56:00.000-05:00

Recently Tornado Alley Turbo has released 2 Service Instructions for Cirrus aircraft. Cirrus in turn, releases a Service Advisory to help ensure that our owners are made aware of these service instructions.

Cirrus service advisory SA11-03 references Tornado Alley Turbo SB11-01 for Exhaust System Inspection, Cleaning, And Lubrication, and SB11-02 for Engine Driven Fuel Pump Inspection.

SB11-01 instructs owners of Turbonormalized Cirrus Design SR22 airplanes to have the exhaust slip joints inspected, cleaned and lubricated on a regular basis to prevent damage to the exhaust.

SB11-02 instructs owners of Turbonormalized Cirrus Design SR22 airplanes to have the engine driven fuel pump inspected for leakage around the mixture control shaft and to have the mixture control shaft seals replaced with alternative seals if needed.

Publish Post

Flap Torque Tube End Fitting Chafing

2011-05-12T09:32:00.000-05:00

We recently released Service Bulletin SB2X-57-11 which calls for an inspection of the flap torque tube end fitting for chafing. This chafing is caused by a misalignment of the actuation arm relative to the end fitting that is affected by tolerance stack-ups within the flap system. It can be easily fixed by using an NAS43 spacer. This service bulletin affects the last 6 months or so of airplanes.

Headset Noise

2011-05-11T10:57:00.000-05:00

The more integrated and electrical that our airplanes and our lives get the more chance for electromagnetic interference (EMI) to cause us problems. A personal example of this is the loud hum the clock radio beside my bed makes due to the cordless phone stand that is next to it.

In the airplane, we go through many tests to ensure that new electric equipment, or new placement of this equipment and antennas don't interfere with other equipment in the airplane. It is an unfortunate reality of the modern airplane.

One current issue we are having is headset noise caused by the Mode S transponder. The transponder is a fairly powerful transmitting antenna. During the Perspective program, we moved the antenna back from the forward cockpit area to its current location in the tail to reduce the potential for EMI issues. Introduction of the Mode S transponder resulted in a more powerful antenna and transmitter and the start of some complaints about headset noise.

Original Forward Transponder Location

Current Aft Transponder Location

The noise heard in the headsets is a clicking noise. Some have described it as the sound an electric fence makes. Some people can't even hear it, and yet for others it drives them nuts. It is more prevalent in the back seats than the front due to the proximity to the antenna.

Extensive troubleshooting and testing both at the factory and at an outside service center found the following results. First although caused by the more powerful Mode S transponder antenna, this is mostly an active noise cancelling headset problem. It is worst in the Bose X headset, and basically non existent in the passive headsets. There is something within the ear cup circuitry that is picking up the EMI. We have had discussions with Bose and they said that the A20 should fix that problem.Ground and flight testing have shown that indeed the Bose A20 and Lightspeed's Zulu's ANR headsets basically eliminate the problem.

Switching headsets is the best short term solution to this problem.

Bose A20 (Left) Lightspeed Zulu (Right)

A longer term option would be for us to try to move the antenna aft. This of course comes with it's own set of issues. The first issue is with the antenna itself. As we move further back, the fuselage narrows very quickly and you run out of places to put the antenna other than through the bondline running down the center. The current antenna connection is designed for thin skin airplanes not thick bonded joints. Therefore an alternate antenna style (ie. a small blade antenna) which meets the required TSO approvals would be required.

This confined space brings up two other design criteria. First you have to consider installation access is only through the small access hole on the side of the fuselage. Combining limited access with the oxygen bottle, the shelf that holds it and the various control cables you are limited as to how far back you can move it. It gets crowded in a hurry. Second with the narrow fuselage you reduce the size of the ground plane. This could likely hurt transponder performance.

Finally any antenna move like this requires a Major FAA project. There are pretty specific guidelines for determining transponder performance and they require a lot of coordination with the FAA and air traffic control for the various in-flight tests of transponder performance. (that is a whole other interesting blog post) So moving the antenna back a few feet will help but it is not a near term solution.We recommend switching headsets in the short term.

Alt 2 April Update

2011-04-29T08:00:00.001-05:00

The final update on our Top 5 reliability project is the #2 Alternator. Teardown of failed units has revealed 2 main failure modes, and their failure rate is pretty evenly split between the two. The first is with the stator. There are several design changes in place already in 2011 that should solve most of these types of failures, and an expensive tool is coming online this summer to further help the build process for this part of the alternator.

The other main failure mode is the diodes. This is actually an assembly of diodes and is manufactured by another company. We have returned 6 of the failed diode assemblies to that company for a detailed failure analysis. Hopefully with more information we can determine the root cause, and a solution.

Flap Relay April Update

2011-04-28T08:02:00.001-05:00

April was spent ordering parts and circuit boards for the test version of our new flap relay replacement. The parts have come in and we are nearly complete building the engineering test unit.Once complete, we will first try it on our bench flap set up, and if that works we will then move to on-aircraft testing to see how it handles use in the real world. As you can see from the picture, the backside of the board has the blades that would plug into where the existing relays attach. This board is about 40% larger than the final board would be as it is just an engineering test unit and that size board was easy to get quickly.

Arrow to SR20?

2011-04-27T16:04:00.000-05:00

I have been a 1/5 owner of a 1967 Piper Arrow for the last 7 years and it has treated me and my family very well. I have flown it to Denver and North Carolina, but most often to visit family in Wisconsin and Ohio. I am now considering changing to a 1/5 share of a 2002 6 pack SR20 with a different group of owners. Of course with all decisions it comes with pluses and minuses. In this case, the SR20 is more expensive than the arrow and it is also located at a different airport.

Financially, I don't even try to justify it. It either fits in your budget or it doesn't (I'm not sure it does yet). However, I live literally 5 minutes from my current airplane which is 1/4 mile from my work. The SR20 is located at another airport which is a 35-40 minute drive away. Now I realize that I live in a great city with zero commute, and this is all relative, but how much emphasis do you put into convenience with a decision like this?

Any advice from my loyal blog readers?

FCM April Update

2011-04-27T08:00:00.000-05:00

In April, we completed a comprehensive on-aircraft test of the new field control module design. The testing was 4 pages of worth of test conditions designed to mimic various power loadings and scenarios. Some of it was done on the ground but most of it was done in flight on one of our experimental airplanes. All testing was successful as expected.

The manufacturer of this part is making 6 "pilot" versions of the new design. We often run "pilot" parts or even whole aircraft down our assembly line to ensure proper training, and to sniff out potential manufacturing issues when running at full line speed. In the case of the field control modules, our vendor will be using these 6 parts to verify their manufacturing steps, and their in-house test procedures and equipment. Once that test is successful then we should be ready to implement these new parts into production.

Pressure Sensors April Update

2011-04-26T08:00:00.000-05:00

Work on this issue has started up again and is focusing on wire security issues near the sensor. Basically trying to reduce the relative motion between the wire and the connector. As this installation is slightly different between the various models of airplane, we are looking into several alternate installations for testing.

We are also planning on applying the baffle connector removal "fix" to a few other fleet airplanes that operate in different climates. This way we gain even more experience, and can ensure the robustness of the installation. The picture on the left shows one of the blue baffle connectors and a version with the connector removed.

April Fuel Quantity Indicator Update

2011-04-25T08:20:00.002-05:00

As I stated last month, all the drawings are released and parts are on order. It is unfortunate that there is a long lead time to get these parts but that is the reality of the supply chain world today. A supplier quality engineer visited the vendor 2 weeks ago and came back with some possible suggestions to improve the lead time, and we did have a telephone meeting with the vendor last week and are working to improve that lead time. Nothing definite yet, but we will continue the discussions.

We are still looking at a late July production implementation, with parts available for the field beginning about 2 months later.

Hands On Training

2011-04-13T08:27:00.003-05:00

For the first time in a while, we were able to offer our composites repair class to in-house staff that do not do repairs as part of their job. This class has some engineering A&P's, a structures engineer, a liaison engineer, and flight test pilots amongst others.Our flight test pilots are often tasked with flying the airplanes after major structural repairs to ensure that the flying characteristics are the same as when they left the factory. By taking this class, they get a better understanding of the work that went into the airplane they are about to fly, and they can understand the repair documentation that goes with it.

The 2 Engineers in the class create and analyze the structural repairs that are sent to the field. They do a lot of damage assessment, and have a good understanding of what can and can't be done, but nothing builds empathy for the technician better than actually doing it yourself. Composite repair isn't hard, but it is precise, and it does take a lot of skill and care to do it right.

The participants are halfway through the class, and every time I see them they have a smile on their face so it must be a good learning experience in a lot of ways.

Spring Vision Jet Update

2011-04-05T16:20:00.003-05:00

We recently went live with our first Cirrus Vision Jet video update. It is available for viewing on our YouTube channel. Watch Paul Brey (VP, Product Development) and Dave Rathbun (Chief Engineer) literally walk you around the V1 test jet and show off the latest progress. After Paul and Dave, Chief Test Pilot Mike Stevens goes into detail about flying the Vision and just how similar it is in many ways to flying an SR22.

Pressure Sensor March Update

2011-04-01T08:46:00.003-05:00

Unfortunately, no real progress was made on the pressure sensor issue in March. We temporarily re-assigned the engineer that is working on the problem to work out some details related to a fleet configuration. That temporary assignment is now complete, and he is back working out the next steps in testing the pressure sensors.

Fuel Quantity March Update

2011-03-31T09:21:00.003-05:00

March has been about coordinating the ordering of new parts for production and the field. We received the final information about the new parts from the vendor and released our drawings. There has also been considerable coordination between our supply chain, customer service, and engineering to determine quantities needed, timing of orders, vendor production capability etc. Orders were made this week for production and a first batch of field replacements. There is still a 16 week lead for this first batch. So these new parts wont hit production until the end of July, and it will take a couple of months after that to have sufficient quantities available for the field. There is a light at the end of the tunnel!

FCM March Update

2011-03-30T07:33:00.001-05:00

March has been busy for the field control module project. The test fixture was completed and the test procedure was written. We then took it down to our FCM vendor to try it out on the existing field control modules and show how the new versions will work. That testing and training was successfully completed with a few minor changes needed.

The next step is to have our vendor make a small prototype batch of the new field control modules, and run them through their standard inspection and testing techniques to verify that they can make them as intended. Drawings are being released for these new FCM's and we hope to have a prototype run in mid-April. With a successful test run, we can then look to making a permanent switch to the new field control modules.

Flap Relay March Update

2011-03-29T07:20:00.001-05:00

Last month's update had us using a test bench to determine the root cause of the problem. Since then much time has gone into designing the schematic for the transistor based circuit board that would replace the relays. The solution will be plug and play with the existing relay installation. Just take out the relays and plug in the new board. So with the schematic complete, parts are now on order and we should have a board built up sometime in mid-April for bench and aircraft testing.

Alt 2 Reliability March Update

2011-03-28T10:48:00.003-05:00

When I last updated the status of Alt 2 reliability efforts at the end of February, we were about to look into the cooling performance of the alternator. An instrumented alternator was sent to us and we installed it into a SR22T. This instrumented alternator had 7 thermocouples mounted on it in various critical locations. Critical climb and cruise profiles were flown and temperatures recorded. In addition, various alternator electrical loads were also flown, from a more typical 25amps to a max of 61amps. Once all the data was collected, correction factors were added to adjust for max outside air temperatures.

In all worst case conditions (high electrical load and high outside temps), alternator temperatures were well below maximum allowable limits. Alternator temperatures at the typical electrical loads were significantly below that. As an additional test point, we taped over a portion of the diode cover (silver tape on picture below) to simulate a possible baffle seal interference, and those temperatures were within 2-3 degrees of the previous test results.

In parallel, HET has been working closely with their diode vendor and doing their own testing to try and determine a possible failure path either with the original design, construction, or installation of the diodes. No smoking gun has been found yet, but work continues.

TKS In-Line Strainer

2011-03-24T14:51:00.007-05:00

Recently a customer sent us a video of a leaking in-line strainer. The in-line strainer is used in TKS system as a secondary method of filtering the fluid. It was first installed in the G3 airplanes when we moved the fluid tank to the wing. A slightly different version of this is used in the FIKI version of the airplane.

In the video it was obvious that the olive was not properly crimped at the factory as it easily slid off the tube. Although there are two o-rings on the fitting along with this olive, improper crimping could allow fluid to leak past the olive and into the airplane.

In the video, the olive slides off

This part comes to us as an assembly from the vendor. Field replacement rates of these parts has been VERY low. A total of 36 of the no-hazzard strainers have been replaced, and 2 of the FIKI versions have been replaced. This results in a 12760 hour MTBF for the no-hazzard version, and a 34,000 hour MTBF for the FIKI version. These numbers are actually higher as several of these parts were replaced in a troubleshooting effort for low panel flow prior to the updated troubleshooting guide being released. So failures for improper crimping have been minimal but we have heard of two.

Proper installation of these olives requires a tool and torquing to a specific angle that is dependent on tube diameter to get consistent results. We discussed the assembly method with our vendor and they confirmed that they use this method of crimping. The pictures below show the assembly fixture and the torquing template that is used.

The blue piece on the bottom in the vice is the clinching tool

The Clinching Template

A properly clinched olive deforms the tube

Obviously what our customer saw and sent to us shows that there was some breakdown at the vendor. Since this assembly was never intended to be taken apart in the field, there are no tools or instructions available to the field to fix this, and part replacement has been the expensive "repair" method. We are currently exploring options to either make crimping tools and instructions available, or allowing people to send in these assemblies for a repaired version. I will update when we know more.

ECS Wire Security Service Bulletin

2011-03-18T07:30:00.000-05:00

Initially discovered during a production flight test inspection, there is an opportunity for chafing to occur on the ECS temperature wire that is located near the rudder pedal. This problem only exists on early SR22T airplanes. We released mandatory service bulletin SB2X-21-04 that adds some chafe protection and adds some wire ties to ensure clearance and reduce movement.

TVS SAIB Revision

2011-03-17T08:24:00.003-05:00

Last month, we released a service bulletin to address TVS failures in pre-Perspective airplanes which I talked about in this post. The FAA followed up yesterday with a Special Airworthiness Information Bulletin (SAIB) revision. The CE-08-12 SAIB was originally released a couple of years ago to describe the problem and reference our service advisory. This revision added a reference to our recent service bulletin and closes the issue with the FAA.

Perspective Fuel Flow TPOH

2011-03-16T08:15:00.002-05:00

We just released a temporary revision to the POH (TPOH) to correct for the proper leaning for max power fuel flow in normally aspirated SR22's. In that later revisions of Perspective software (version 0764-02 and later), the fuel flow indicator green arc is dynamic based on engine parameters. The target max power fuel flow is the top of this green arc. There are 2 separate pages to be updated, one with the indications and markings in Section 2 here, and one with instructions in Section 4 here.

Oil and MP Sensor Update

2011-03-07T09:42:00.004-06:00

The last area of the Big 5 reliability that I need to update on are the oil and manifold pressure sensors. Since December, one of our fleets has modified some of the airplanes to remove the mate-n-lock connectors from the harness (blue and white connector in the picture below). We then put a bunch of time on the airplanes to see how they behaved after this modification.

For the most part, all the sensors have been performing well after the modification. However, there was one case which continued to show erratic indications. After further investigation, we discovered that there was one case of corrosion on the connector at the sensor (black connector on the right side of the picture), and another where the contacts appeared to be loosening over time. This was surprising to us as this is a quite robust connector.

So while all of our initial investigation has been with the baffle connectors, we now are also exploring ways to reduce the relative motion between the connector and the sensor, and the wires and the connector. We will be doing more testing in the near future including some vibration testing, and some modifications to the fleet airplanes to verify our results. The likely solution will be some combination of the two.

Vision Jet Progress

2011-03-01T11:15:00.001-06:00

As part of an ongoing series detailing conversations from our Inside Cirrus Events around the country, Cirrus Aircraft News has been summarizing the common questions and answers. The most recent one is written by my boss Paul Brey, and summarizes the status of the SF50, what we have accomplished in 2010, and our plans for 2011. I encourage you to check out the SF50 Progress.

Fuel Quantity Update

2011-02-25T09:52:00.003-06:00

Time in service testing continues with our fuel dials. We have over 53 hours on one airplane, and 66 hours on another. We recently switched the dials from one airplane to another to allow for better measurement recording and to build time more quickly. An example of the type of measurement recording we do is pictured below. We are looking for consistency in the data over time. Making sure the lines are overlapping without the erratic behavior seen in the current dials over time.
Similar to the field control modules, since the time in service testing is going well so far, we are beginning to look at the lead times for production implementation and field retrofits. The TKS versions of this dial had an 18 week lead time, and then it took another 2-3 months to build up stock for field replacements. So assuming a similar time frame we are looking at late Q3 for this to hit the field if we ordered today.

Like the other items in our top 5 reliability focus, we remain concentrated on these items, with weekly meetings and an intense internal spotlight to find and implement solutions as quickly as possible.

Field Control Module Update

2011-02-24T15:32:00.003-06:00

Time in service test of our redesigned field control modules is at 60% of planned as of today. Our focus in February has been on designing the new test equipment. That design is complete and parts were ordered and received. So over the next few weeks we will be putting that equipment together but more importantly we will be writing the test procedure and documenting our test equipment design. Once that is complete, we will provide on-site support and training with our vendor as they begin to use the machine. Also with the time in service testing going so well, we have begun to discuss production implementation plans. More on that in March.

Flap Relay Update

2011-02-23T08:10:00.000-06:00

We were able to make a little progress over the last month on the root cause of the flap relay failures. We created a bench test that allowed us to view all the components under various conditions. This bench test was also used to test a couple of possible solutions.

We also were able to analyze flight data from one of our flight schools and compare it back to their maintenance records for flap relay replacements. We found that failures occurred anywhere between 300-3000 flap operations with an average of 1300 flap operations. Of course in a flight school environment with high amounts of landing operations, this adds up quickly.

All the bench testing and analysis helped us determine that the relay contacts can bounce while electronically braking the flap motor. Eventually the resulting arc welds the contacts and causes the relay to become stuck in one position. In the coming month we are going to prototype a circuit board to test out some permanent fixes both on the bench and if successful, on an airplane to eliminate these arcs.

TVS Fuse Installation Service Bulletin

2011-02-22T08:09:00.005-06:00

Yesterday we released SB2X-24-09 TVS Fuse Installation. Problems with these transient voltage suppressors (TVS) began back in 2007 and are not unique to Cirrus, having also affected other airplanes and avionics manufacturers. Back in 2007 we worked closely with those other OEM's and the FAA to determine the root cause and correct course of action.

Transient Voltage Suppressors are a major component of the lightning protection system on Cirrus SR20 and SR22 aircraft. During lightning strikes, enormous energy spikes can be induced within the aircraft electrical system. In the absence of any transient protection, this unwanted energy would typically be dissipated in the form of high-voltage discharge across the avionics and electrical systems of the aircraft. By adding a high power TVS at key power entry points on the electrical busses, unwanted energy from electrical transients is allowed to dissipate through a semi-conducting pathway to ground. Acting much like a lightning rod, the TVS (under high-voltage conditions) protects the pilot and aircraft by channeling damaging voltage away from the aircraft electronics and into the localized grounding point.

In 2007, Cirrus released Service Advisory SA 07-17 advising operators of the possibility of TVS failure and to provide guidance on how to handle a failure. In 2008, the FAA issued Special Airworthiness Information Bulletin CE-08-12 advising affected Cirrus operators of an airworthiness concern where possible failure of a TVS may result in an increase in pilot workload.

While Cirrus believes the majority of the affected TVS in the field have been replaced thru part attrition, we recommend installation of an in-line fuse per this Service Bulletin to prevent a TVS failure and the possibility of smoke and fumes from entering the cabin in the case of an over voltage event.

Alt 2 Reliability Feb Update

2011-02-21T09:21:00.003-06:00

I posted in December that we are focusing on our top 5 reliability issues this year. I intend to update you on the progress at least monthly. First up this month is Alt 2.

As I mentioned last month, we are making it a priority to get failed alternators back to Hartzell Engine Technologies (HET) so that they can get inspected for a root cause failure analysis. Since Jan 20th, HET has received 20 alternators, 13 of which are from the K (2010) date code. 6 of those exhibited a common failure mode of a shorted diode pair. Signs of overheating were also seen on these failed alternators.
We are exploring several root causes. HET is exploring the diodes and their performance to specifications because once a diode fails short, localized heating will definitely follow. Cirrus and HET are also going to verify the cooling performance of the installation. Cooling testing is done with an alternator instrumented with thermocouples at critical locations. I discussed this process briefly in a previous blog post. This testing was done in spring 2008 when Perspective was first introduced, and again in fall of 2009 for the SR22T certification. Little has changed with the baffle over the last few years, but it is certainly possible that all the little changes we have made may have added up over time. So we hope to do this testing sometime in March.

As mentioned last month, several updates were made in 2009 and put in place for the 2010 models. Additional design and manufacturing changes are scheduled for 2011 as well. The first of which was the addition of some epoxy in critical areas. This was put into production in February. Another design change will be implemented in the next couple of months, and change in manufacturing equipment will be in place in Q3 of this year.

We will continue to analyze failure modes and make constant improvements based on those results.

TKS Quantity Indication

2011-02-17T15:07:00.002-06:00

At the end of January, I posted that we had put new TKS quantity sending units into production and that they were also available for field replacements. Some customers asked if this was only applicable to FIKI airplanes or was it also available for the pre-FIKI G3 airplanes with only one tank and level sender. The answer is yes, it is available for both and they use the same part number.

The new part numbers are 21992-002 (RH) and 17382-006 (LH)

Glowing Nose Landing Gear

2011-02-15T08:48:00.002-06:00

Our main landing gear are heat treated to increase their strength. A picture came floating through the office last week of our nose landing gear entering the quench cycle of the the heat treating process. I thought that seeing these steel parts glowing orange was pretty interesting so I am sharing the picture with you as well.

CAPS 10 Year Overhaul Process

2011-02-07T10:15:00.004-06:00

Platinum Aviation, one of Cirrus' service centers located at KFXE in Florida, recently published a series of blog posts about the process of replacing the CAPS system at the 10 year interval. A lot of care goes into doing this properly as this blog shows. You can see their excellent blog here, or follow the links below for the 4 part CAPS overhaul series.

Cirrus CAPS Replacement - Watch The Process
Cirrus CAPS Overhaul - Part 2
Cirrus CAPS Overhaul - Part 3
Cirrus CAPS Overhaul - The Final Reveal

SR22 10th Anniversary

2011-02-01T08:37:00.004-06:00

Yesterday marked the 10th anniversary of the SR22. The certification for the SR22 began in February 2000 which is when I was hired by Cirrus. The structural analysis of the SR22 wing was the first project I did when I started at Cirrus. I remember watching the first flight of an airplane with that wing, and all the structural testing that went into that project.

My first flight in an SR22 occurred in August 2001 when I flew an airplane back to Duluth from the Hibbing paint shop with a production flight test pilot. But I didn't get any significant flying time in an SR22 until January 2003 when I ferried an airplane to Hayward California smiling the whole way.

Yesterday during our company meeting celebrating this milestone, I was reminded how much this airplane has changed and improved over the years. The first one delivered didn't have a glass cockpit, that came a couple of years later when we made the Avidyne PFD standard equipment. We have added XM weather, TAWS, air conditioning, air bag seat belts, G2 and G3 variants that reduced the empty weight, basic ice protection, turbo-normalizing, Garmin avionics, digital autopilot, flight into known ice (FIKI), and ESP in the last 10 years.

I know that I tend to get focused on the current project and forget past projects with the long hours at work away from your family, the struggles and set backs experienced, and just the shear volume of work, and most importantly, the many many successes we have experienced over the last 10+ years here. But this kind of milestone gives me an others a chance to reflect and be proud of all that we have accomplished to make the SR22 the best airplane in it's class.

Alt 2 Reliabilty

2011-01-31T08:38:00.004-06:00

The reliability of our 80 amp #2 alternator has been under scrutiny for a few years now and we are beginning to see the affects of all the design changes that have been made. 2 weeks ago, we had an "alternator summit" here at Cirrus. Hartzell Engine Technologies (formally Kelly Aerospace) and TCM were here for an all day discussion on alternators.

Failed alternators are sent back to HET for a root cause analysis, and we reviewed all the design changes that resulted from those inspections. Most of those design changes were implemented at the end of 2009 and hit our production the first part of 2010. Since then, the alternators built and installed in 2010 appear to have an improved reliability however there isn't enough hours on those units to make a good comparison.
But the improvement didn't stop in 2009. Throughout 2010 more design and manufacturing improvements were made to the stator, rotor and diode cover, and the implementation of these changes continues to occur through the first quarter of 2011 which should make the reliability even better.

Cirrus has made it a priority to get failed alternators shipped back directly to HET so that they can perform a tear down and diagnose the problem. All these tear downs are witnessed by the VP of Engineering to ensure the proper level of oversight. We will continue our bi-weekly telecons with HET, root cause analysis of failed units, and continuous improvement of the product design and manufacturing.

Flap Relays

2011-01-28T10:47:00.002-06:00

The 4th area of reliability focus this year is flap relays. Although the general fleet sees good reliability with this part, some of our flight school users who have high numbers of take offs and landings have a much higher failure rate. We started doing some tests in the lab this week, and don't have a root cause or solutions determined yet.

Pressure Sensors

2011-01-27T10:51:00.005-06:00

The 3rd area of focus for reliability in 2011 are oil and manifold pressure sensors. We started investigating this in detail in Q3 2010 and I posted our plans and findings back in October. Since then we determined that the "failed" sensors were actually functioning just fine as we suspected.

Our leading suspect was the mate-n-lock connectors at the baffle. As is often the case with intermittent items like this, we had a hard time seeing them we our engineers were on board. Our modern avionics give us the ability to record data so one of our engineers developed a tool to help us see these erratic indications and determine if they were getting worse over time. This tool takes all this data over time and shows a "jumpiness index." The example below clearly shows MP getting erratic after 100 hours, and Oil Pressure after 250 hours. It also shows that it doesn't happen on every flight.
With one of our fleet operators who was experiencing significant issues with erratic indication, we removed these mate-n-lock connectors from about half of their airplanes and are just running a direct wire from the firewall connector to the sensor connector. 500+ total flight hours later they have had no issues at all. They are going to apply this to their remaining fleet and continue to build hours on this solution to verify performance.

These mate-n-lock connectors are used for other sensors as well as we need a good connection at the baffle and a way to remove the hard-wired sensors. The oil and MP sensors have a connector right at the sensor, most of our other sensors don't so we have to have a way to easily replace them in the field. So we will be looking at alternative connectors as another solution to this and other potential problems.

Field Control Modules

2011-01-26T15:05:00.004-06:00

The second of the top 5 reliability areas under focus this year is field control modules (FCM). Mid 2010, we began an in depth look at the design and manufacturing of the FCM. This resulted in recommendations for a few design and manufacturing testing changes.

We made the design changes, did extensive bench testing and are now ensuring that they behave as expected in normal flight operation by flight testing them. We are about 40% complete with the flight testing portion.

In parallel to this redesign effort, is the effort to ensure that we are testing this new design properly at the manufacturer. We are making a few changes to the test hardware and the test procedure to ensure a robust test procedure. The FCM's are tested by themselves, and then again as a system when installed in the MCU. All our testing changes are at the mid-level test point where the FCM's are tested individually.

Once we are confident that the design change works and the test procedures are in place for this new design, we will be making the permanent production change, and making these available for spares in the field. Provided the testing goes well, we could implement this in Q2 2011.

Fluid Quantity Indication Update

2011-01-25T14:30:00.004-06:00

As I mentioned at the end of the year, fluid quantity indication was one of the Top 5 reliability items we are focusing on in 2011. My last update on this topic was 6 months ago when we had completed our testing of a new TKS quantity dial, and experienced a failure on the fuel dial we were testing.

TKS Quantity:
There was a long lead time (4 months) to get those new dials from the supplier, but the new dials are now in production as of December. Quantities for field replacements have been ordered, and the new dials are available through Cirrus Parts by API. We will continue building up our stock of replacement parts over the next few months. As a side note, the test parts remained installed in the test airplanes for the last 6 months and have continued to show accurate and steady readings after another 100 hours or so of flight time.

Fuel Quantity:
Fuel quantity indication continues to be actively worked on. We have 2 different technology solutions in work, one is being bench tested for a million cycles and will be installed on an airplane for flight testing soon. The other solution has completed bench testing and is currently installed in airplanes for time in service testing. We are using 2 different airplanes to build time, one has 40 hours and the other has over 80 hours. The new fuel dials are behaving very well as expected. We will continue to build time on these airplanes to ensure that we have a solution that will last. As much as we want to solve this problem quickly, we don't want to put out a solution that is only marginally better than the existing units. Our expectation is to test these airplanes for a few more months to try and build another 100 hours or so then make the change for both production and the field similar to what we did for the TKS dials.

Cirrus and ADS-B

2011-01-11T13:38:00.006-06:00

Cirrus is now offering an ADS-B capable option on new aircraft. Installing a Garmin GTX 33ES transponder gives you the ADS-B "out" capability per the 2020 mandate. To add the ADS-B "in" capability you must also have the Garmin GTS 800 traffic advisory system installed. Together these meet the requirements for the 1090ES ADS-B standard. This allows the Cirrus airplane to receive ADS-B traffic from other ADS-B equipped airplanes.

Note: The installation of this ADS-B compatible equipment does not provide FIS-B capability (i.e. weather). FIS-B information is not available on the 1090ES frequency and is only available through equipment that supports the UAT standard for ADS-B.

ADS-B is in it's infancy. The FAA and industry are still trying to figure out what the final implementation standards will be. However Cirrus will be ready with the latest capabilities when a consensus is reached.

Hypoxia Prevention and Automatic Descent

2011-01-07T14:58:00.005-06:00

One of the really great features with the latest Perspective software release was the hypoxia prevention and automatic descent. This feature is intended to recognize when a pilot may be experiencing hypoxia and then descend the airplane to an altitude where the pilot can regain control of the aircraft.

The software does this by recognizing whether the pilot has interacted with the avionics system (button push, knob turn etc). The time between interactions decreases the higher the altitude per the table below.

Altitude X Interval
15,000’ 1800 sec (30 min)
18,000’ 1200 sec (20 min)
22,000’ 600 sec (10 min)
25,000’ 300 sec (5 min)
28,000’ 60 sec (1 min)

Continued non-interaction with the aircraft or response to increasing visual and audible warnings leads the software to believe that the pilot may be suffering from hypoxia and likely unconscious. The airplane will then use the autopilot to descend to 14,000 feet initially, then down to 12,500 feet after that. These lower altitudes will hopefully allow the pilot to regain consciousness and control of the airplane. A flow chart (thanks Brad) of the steps is shown above.

We are very excited about this safety feature and look forward to future enhancements.

Edited 1/10 to add the time between interaction table.

Happy New Year

2010-12-31T08:42:00.002-06:00

I reflect back on 2010 with great pride on the things we accomplished, and I look ahead to 2011 with excitement about all the things we are going to do. This blog has been active for nearly a year now and I continue to be excited about sharing our hard work with you.

I wish everyone a safe and prosperous new year.

Perspective Software Update

2010-12-30T08:37:00.003-06:00

Coinciding with the release of ESP is the release of a Perspective software upgrade (v0764.09). This software upgrade allows the base software support for the installation of ESP (which needs the separate service bulletin done to activate it), but it also adds a bunch of other desired changes. The following was taken from service bulletin SB2X-42-06R1.

Software Change Synopsis

GFC 700 AFCS
(a) Added Electronic Stability and Protection (ESP) base software support (requires installation of SB 2X-22-07 R1 or later revision to be functional).
(b) Added Under Speed Protection (USP) for coupled autopilot operations.
(c) Added Hypoxia Recognition with Automatic Descent.
(d) Changed Go-Around (GA) function to support coupled Go-Arounds; the autopilot does not disengage when the GA button is pressed.
(e) Changed AP DISC function so that the Flight Director (FD) is also removed when the AP DISC button is pressed.
(f) Improved the response to a LVL mode recovery.

Moving Map / MFD / FMS
(a) Improved FMS user interface by adding a joystick controlled precursor insertion point on the flight plan page
(b) Added graphical METAR symbology to the MFD map and flight planning page.
(c) Added an altitude intercept symbol on the MFD map to predict the point at which the bugged altitude will be captured.
(d) Added a selectable flight plan profile view to the MFD map.

Database / Data Logging
(a) Fixed an issue that sometimes occurred when updating from a Standby to Active NAV database.
(b) Minor changes to the Recoverable Data Module logged data.

FAA Approves ESP

2010-12-23T08:22:00.000-06:00

After over 16 months of working closely with both Garmin and the FAA, the FAA has approved our Electronic Stability and Protection (ESP) project. A lot of work by our Engineering Flight Test and Avionics and Electrical Groups went into this project and we are very excited by the results and where this technology will lead us next.

The official announcement is here, and the online brochure is here.

Top 5 Reliability for 2011

2010-12-21T09:55:00.000-06:00

As 2010 winds down and we look ahead to planning 2011, my group's biggest focus is going to be on implementing design changes that have a measurable affect on reliability. I have chosen to attack the top 5 least reliable parts as the way to create this change. Some of these are Cirrus parts, others belong to our suppliers, so this will take a focused effort between many people in multiple companies to achieve the success that I want.

These parts are: Alternator #2, Flap Relays, Field Control Modules, Fuel Quantity Indication, and Oil and Manifold Pressure Sensors.

Over the past year, I have talked about several of these in this blog over the year and all of them are in various stages of being worked. Some have solutions that are going through time in service testing, others are in earlier stages of root cause investigation. All will be tracked at the group level on a weekly basis, and at a management level on a monthly basis.

Second only to safety, reliability means a lot to me, as it directly ties into utility and cost of ownership for the airplane. We focus on this heavily during the design phase. Most of the time we are successful, other times we aren't. We are aggressively going after these issues but these things do take time as some are easier to solve than others and we want to make sure that our design fix actually solves the problem.

So I look forward to continued sharing of our successes and struggles with these 5 parts in the coming year.

Cirrus Hosts FAR 23 Icing Rulemaking Committee

2010-12-13T07:45:00.001-06:00

Last week Cirrus hosted the aviation rulemaking committee (ARC) for FAR 23 flight into known icing. This was the 4th of five planned meetings of this committee in the last year. Forming of ARC's is common now to ensure that all the expertise in the industry and FAA is involved in creating new rules or guidance. This FAR 23 icing ARC follows the release of a notice of proposed rulemaking (NPRM) for FAR 25 flight into known icing earlier this year. The purpose of this ARC is to help formulate the icing regulations and advisory circulars for Part 23 airplanes and Part 33 engines. This ARC is composed of representatives from the FAA, airframe and engine manufacturers, and industry icing experts. 13 representatives were at Cirrus last week for the meeting. Together they go through the current regulations and advisory materials, proposed Part 25 regulations and advisory materials, and determine what is appropriate for Part 23 airplanes. The end result is that the ARC will submit rule change recommendations and provide suggested wording for advisory materials to the FAA. The FAA is then expected to take these recommendations and formulate a NPRM for Part 23 airplanes in the next year or so.

Service Bulletin for deployment bag straps

2010-12-06T13:45:00.006-06:00

One of the things we have found during the first 10 year CAPS overhauls is that in limited cases, the red nylon strap that holds the chute deployment bag in the bucket has shown signs of chafing on the unprotected edges of the bucket.

This chafing does not hinder parachute deployment and with the majority of the fleet going through CAPS overhaul in the next few years it provides a good time to fix this. Last week we released service bulletin SB2x-95-13 that will open up the holes a little bit and add a grommet to protect this strap from the edges of the composite bucket.

Visit to Grand Forks

2010-11-24T12:00:00.003-06:00

With a gap in winter weather systems yesterday, I got the opportunity to fly out to visit our Grand Forks facility. It has been close to 2 years since I had last been out there. Our Grand Forks plant does all the composite part layup, cure, and trimming. Once a week, a truck hauls a weeks worth of composite parts from Grand Forks to Duluth where they are bonded together and assembled into the final product.

It was amazing to see the transformation they have gone through over the last couple of years. Like the rest of our manufacturing operations, we are constantly looking for ways to improve process flow, eliminate waste, and improve quality and safety.

The flow of parts has changed dramatically from my last visit. Rolls of raw material now comes in on one end, and after following a big loop through the plant, it returns to the loading dock, cured, trimmed and inspected, awaiting the truck to take it to Duluth.

The technicians know what they are going to be working on each day, and many key indicators such as process time and quality are tracked and posted for everyone to see. Process Engineers work directly with the technicians on the floor to find improvements in process and safety.

It was good to see all the positive changes, and how everyone is focused on continuous improvement. Hopefully it wont be another 2 years before my next visit.

Turbo Service Advisory

2010-11-22T16:09:00.003-06:00

Cirrus recently published service advisory SA10-14. This service advisory references service bulletin SB 040 from Hartzell Engine Technologies and involves a problem affecting certain turbocharger center housing rotating assemblies (CHRA) where debris may not have been removed after the machining operation. The debris could enter the normal oil flow to the turbine wheel shaft assembly resulting in seizure of the shaft and/or turbine wheel head separation.

The service bulletin directs inspections of all new or overhauled turbo center housing rotating assemblies with less than 50 hours of service to identify affected parts with a specific foundry marking. Those parts affected should follow the instructions in the service bulletin for removal and cleaning.

SR22T Service Bulletin

2010-11-22T16:02:00.003-06:00

After the first SR22T's went through their 25, 50 and 100 hour inspections, Cirrus service centers around the world found a few issues and quickly informed Cirrus Engineering of what they found and sent pictures to help explain the issues. This feedback is immensely helpful, and allowed Cirrus to tell the other service centers in the network about these possible problems to prevent any of them from becoming major issues.

Engineering used this information to determine permanent fixes for both new production airplanes and the airplanes in the field. Cirrus has made several changes on the production line to prevent these issues from happening in the first place.

To address the airplanes in the field, Service Bulletin SB2X-72-01 was released today. The service bulletin calls for inspection of various areas for chafing, and installs some new parts to reduce or eliminate the possibility of chafing. This mandatory service bulletin should be performed at the next inspection interval or 100 hours whichever comes first.

Winter already?

2010-11-18T15:32:00.003-06:00

I haven't posted anything in a while but that doesn't mean that things are slowing down in Engineering. On the project side we have been finishing the last of the reports and flight testing for ESP certification. On the field support side, we have a few different service bulletins and advisories coming. I will have more specific posts on each of those in the coming days.

We got almost a foot of snow over the weekend at the airport. So winter has arrived. Time to get the snow boots and shovels out, and prepare for winter flying season. I love flying in the winter, but it does have it's downsides of preheating, slippery taxiways, icing, and short daylight hours. With a BFR, some instrument recurrency training, and a possible flight to Chicago ahead of me in the next month, I will be getting my share of early winter flying.

Cirrus News

2010-11-03T15:04:00.006-05:00

My blog experiment here has been successful, and my posts are now also published on the Cirrus news portion of the Cirrus Aircraft website. This Cirrus news section has been revamped to allow information from several areas of the company to be posted in one location. Currently Engineering along with general Cirrus news and announcements are available there. Flight training and customer service will also be posting shortly.

One of the nice things about the new Cirrus News website is that you can link to just one of the categories (like engineering) that interest you. I have added a links section on the right side of this blog page with links to the main Cirrus News page along with the Engineering news link.

Cirrus News
Cirrus News/Engineering

As I mentioned in my first blog post, my goal of this blog was to share our successes and our struggles and to provide a glimpse into the life of Cirrus Engineering. I have tried to provide some good information on design compromises, field issues, and new development programs. I also shared some personal experiences about working with a group of people who are nuts about airplanes which I hope you enjoy.

Comments about this blog or any other engineering issue are always appreciated and you can reach me at ttimmerman@cirrusaircraft.com

Enviro Air Conditioning Bushings

2010-11-03T15:00:00.007-05:00

The Enviro air conditioning system compressor assembly mounts to the back of the engine. The drive shaft hub assembly is part of the lower assembly that is driven directly by the engine. A pulley is bolted to this drive shaft hub assembly, which through a belt drives the compressor. When this compressor was originally designed, there was no maintenance provision for the drive shaft hub assembly.

Service experience revealed that the original rubber bushings which surround the four drive shaft mounting bolts wore down prematurely resulting in a metal on metal condition. This metal on metal wear results in either a shear failure of those four drive shaft mounting bolts or a worn out bearing. Both of which require required the replacement of the entire drive shaft hub assembly because of the significant damage. A timely solution to the root cause problem of premature wear of the rubber bushings was not possible, so to prevent the more significant repair and replacement, the rubber bushings and guidance for the removal of the drive shaft hub assembly in the field to replace those bushings was provided.

A definitive redesign of the drive shaft hub assembly is now available as a spare for the field (21119-110). This new design makes several configuration changes and replaces the existing rubber bushings with a three-piece design that will be far more robust than the original configuration.

The AMM specifies 100 hour inspections of this part, and it is highly recommended that those who experience field issues with the rubber bushings wearing out replace the entire drive shaft hub assembly as this will solve the root cause problem. However, Cirrus will continue to make the rubber bushings available for those who do not mind making regular on-condition replacements.

Edited to add the new drive hub assembly part number

Pressure Sensor Update

2010-10-27T13:20:00.004-05:00

As I discussed in a previous post a couple of weeks ago, we were exploring several different root cause explanations for the erratic behavior of the oil and manifold pressure sensors. Here is an update as to what we have found so far.

We returned 7 faulty sensors to the vendor for them to test. Tests revealed that only 1 of the 7 sensors had any fault. So as expected, it likely isn't the sensor that is the problem. The one failed sensor had less than 20 hours on it and the root cause was an open trace.

We have removed the mate-n-lock connector and spliced the wires on 3 airplanes now. One of which was done with a "faulty" sensor still in it. All 3 airplanes have not reported any erratic behavior since the repair was done.

We still are going to build significant time on these airplanes to ensure we have a root cause and a potential solution. We are also continuing to splice wires in the remaining airplanes in our fleet customer to help build time on this repair method.

Left My Airplane Behind

2010-10-26T15:42:00.003-05:00

This past weekend I made a common fall trip between Duluth and Green Bay Wisconsin. My parents live in Green Bay, and I go to a few Packer games every fall. This week the game was against the dreaded Minnesota Vikings, so my 4 year old daughter and I piled into my Arrow and made the trip over on Saturday morning in some light rain.

I intended on returning to Duluth on Monday morning but watching the weather all day Sunday it didn't look good. In fact Monday morning it looked even worse with widespread IFR conditions, and below minimums in Duluth. With no good alternate within 200 miles, and the weather forecasted to be worse on Tuesday, I decided to scrub the trip, rent a car and leave the airplane in Green Bay.

It was an easy decision to make, and I got home at 8pm last night. I will make the drive back on Friday to pick up my airplane when the weather is looking sunny and dry. Looking at the nasty weather we are having today makes me glad I am sitting at my desk at work.

Vision Jet Update

2010-10-22T13:18:00.000-05:00

Our latest Vision Jet update was released earlier this week. It is now available on our website. Come see it at http://www.cirrusaircraft.com/vision/CirrusVisionUpdateOctober2010.pdf

AN-124

2010-10-21T13:19:00.004-05:00

Yesterday afternoon my phone rang. It was one of our Program Managers who happens to sit by the windows facing the eastern half of runway 9/27 here at DLH. She was calling to tell me that an Antonov AN-124 had just landed. A crowd quickly gathered at the windows to see this giant cargo plane park on the midfield ramp.

I blogged before about this airplane that belongs to Polet airlines and is one of the few AN-124's in civilian service. According to flight aware, it came here from RAF Brize Norton in England. Duluth is on the great circle path between California and Europe so we often get airplanes stopping here eastbound for gas, or westbound for customs and gas.

This morning at 7:15 when I came to work, the airplane was fired up and began to taxi westbound for departure on Runway 9 and disappeared from my view. As I was waiting for the airplane to depart, a FedEx airplane landed on 27. That's when I noticed that the wind was pretty strong out of the west.

Sure enough, a few minutes later, the airplane back taxied down 27, exited back onto the taxiway and then to beginning of runway 27. Apparently it has such a wide turning radius, it couldn't make the turn from the midfield ramp onto taxiway A. Below is an airport diagram where I show it's circuitous path to depart.

It successfully departed about 7:35 this morning on it's way to El Centro NAF in southern California.

Oil and Manifold Pressure Sensors

2010-10-13T12:40:00.007-05:00

I recently received some comments from a customer survey regarding oil pressure sensors and the problems that this owner was having with them and the lack of dispatch reliability that results. As an aircraft owner myself (although not a Cirrus), I completely understand the frustration that goes with aircraft reliability. So I wanted to update you as to what we are doing about this problem.

These sensor issues involve both the oil pressure and the manifold pressure sensors which are identical parts and are installed and wired very similarly. Although it is little comfort to those affected, this is a known issue to us in Engineering. In fact it is one of our top 3 field issues that we are working on here in Engineering.

These sensors are the same sensors we have been using for a long time with occasional problems over the years until recently. Now we are seeing more infant mortality failures , and repeat failures within a few hours. This is relatively new to us.

We are exploring 5 possible causes for these erratic indications. To help us expedite our troubleshooting and solution evaluation, we are working directly with one of our fleet customers who is also having the same problems at the same sort of frequency as you.

1. The sensor: We are actually quite confident that the problem is not with the sensor itself, but rather with the wiring from the sensor to the Garmin system. In working with this fleet customer, we have received a couple of dozen sensors that exhibit erratic behavior and we are sending them back to the vendor for testing. Those parts were sent out yesterday and we expect results in a couple of weeks.

2. Poor or erratic connections within the white plastic mate-n-lok connectors. To try and isolate the problem to these connectors, we are going to remove them and splice the wires together to determine if it is the connector that is the problem. We will also explore whether there are some poor manufacturing techniques (crimping, pin setting etc) that may be part of the problem. In parallel, we are also exploring the use of different connector types to replace the mate-n-lok style. The splicing of wires on an airplane will be happening this week when it comes in for maintenance.

3. Grounding. Currently both of these sensors are grounded to a bar mounted to the firewall. Part of the problem could be some sort of interference caused by this grounding point. We are going to modify another airplane and change the grounding point to the GEA where the sensor power wires go to. This modification will also occur in the next week on a different airplane.

4. Software. This is highly unlikely, as these are standard sensor types that Garmin interfaces with. During the course of the other troubleshooting we are keeping this in mind and will work with Garmin if needed to address signal buffering or other possible changes. Evaluating this possible problem will wait until we have results from the changes we make for #1-3 above.

5. Connection between the harness and the sensor. Although seemingly less likely than #2, we will also explore possible connector issues directly at the sensor. This sensor is unique in that it is not “hard wired” like most others and requires a connection right at the sensor. This of course makes it easy to change the sensor out, but if the problem is on the harness side, you will likely have problems soon after the installation of the new sensor. Similar to #4, this evaluation will wait until we have results from #1-3.

So to sum things up, we are working very hard at trying to solve this problem. It is one of our top priorities. We are working closely with a large fleet of airplanes, that builds time rapidly. This will help us to troubleshoot and evaluate solutions quicker. Although I cannot promise a time frame for a solution, I can assure you that we will release a solution as soon as we have one and are confident it will work for the long haul.

Service Bulletin Revisions

2010-10-12T09:50:00.003-05:00

We just released a couple of revisions to some recently released service bulletins. Although we try very hard to prevent this additional work, sometimes we get feedback, or other information comes to light that shows us we have to revise the bulletin.

As an example, in the case of SB2X-27-09R1, one of our service centers discovered that we were missing a couple of steps to verify that the aural alert worked. Namely we forgot the step to turn the Batt 1 and Avionics switches on. Although this will be plainly obvious to the mechanic doing the work (can't test the avionics if they aren't on), we decided to revise the bulletin to ensure accuracy.

The 2nd example involves SB2X-77-03R1. This service bulletin was revised due to changes in effectivity. In this case, there were a couple of airplanes that we thought would be delivered prior to the arrival of parts for production, and thus were put on the Service Bulletin. The parts arrived a few days earlier than expected, and we were able to install the new parts before they delivered. So we revised the Service Bulletin to capture this.

Service Bulletins go through a very thorough checking process, and a verification in our own service center. Revisions, are uncommon, but we do them when necessary. We encourage feedback on all of our technical publications.