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Dynon Heated AOA/Pitot Service Bulletin

Dynon

Well Known Member
Advertiser
Dynon Avionics has released a technical service bulletin that pertains to our Heated AOA/Pitot Probe. If you own this product, please read the service bulletin it in its entirety. In addition to the technical details, there are some important topics covered in the Frequently Asked Questions section after the bulletin that will answer many of the questions you may have.

Note that we are not issuing a product recall at this time. Heated AOA/Pitot Probes that are currently installed in aircraft may continue to be used, subject to the Operating Recommendations section in the service bulletin.

Thanks to those of you that have reported your experiences (Jon Thocker, Stephen Christopher, I know I'm missing a few others from here) - your reports have been valuable in helping us home in on the root cause here.

Michael Schofield
Marketing Manager
Dynon Avionics
 
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Wow. Big admission Michael. Thanks for putting this out. Probably even harder to put a straight out ship-stop on the pitots. That probably puts a big cramp on anyone designing their Skyview / AFS systems currently.

I'll go ahead and ask the general forum... Anyone know if the G3X pitot/AOA, being the same general design, would work with Skyview / AFS? I still have time, and am hanging on to my Gretz probe + the "old" AFS AOA wing-port system for now.
 
Thanks to Dynon for treating the reports of pitot icing seriously, confirming them and doing the work to understand the problem and identify a course of action.

This is the sign of a good company. Stick with them.
 
We haven't tested it in flight, but the GAP 26 looks to use the same general AOA-detecting principles as our AOA/Pitot. We suspect the AOA function would work fine with Dynon/AFS EFIS systems. We do plan on getting ours back on the market soon though (sorry no dates yet)!
 
This here is one of the many reasons why I believe in the Dynon company.

Big call and serious about not only fixing it but communicating. Something most in this industry could learn from.

In 1000 hours of IFR flight we have never had a problem, but that does not mean it does not exist. I expect it happens mostly when in known icing conditions, or heavy rain followed by low temps. Something not easy to replicate.

Good work Dynon!
 
Me too!

I have experienced lost/degraded airspeed indications twice when flying in sub-freezing conditions with the Dynon pilot heat turned on. On one flight through moderate rain (not in freezing conditions) my airspeed was degraded by water collecting in the pitot tubing at the low point (near the wing/fuselage junction). Nice to see that Dynon is addressing the problem. I am confident they will come up with a solution and resolve the issue for good. Great customer support at work here!
 
That is interesting, I am surprised that the rain managed to get in the tube, travel up the stem and then up into the wing, before then being ables to get down to the low points in the system.

In a closed system this is pretty severe. It makes me wonder if there are some Pitot leaks allowing air to flow through the tube system. :confused:
 
David, it's my understanding (and could easily be wrong) that the freezing is in the aft section of the pitot, not in the lines inside the wings. This has been discussed on and off for at least two years. It's the reason I pulled the installed Dynon off of my project way back then.

Back when I worked for Chrysler R&D, if a known problem took more than a week to diagnose, higher ups started calling. By the end of that month we had a proposed fix, life tested and verified or someone was standing on the carpet discussing his employment. Typically there was one tech and one engineer assigned to the problem though in a case where fire was involved they gave us two techs.

When life safety is concerned, these things need to move faster than this pitot issue has. If someone had gotten killed...where would Dynon be? I have Dynon in my panel so not hating...just a voice of experience offering some advice. Dynon can and should do better. Running a life test with rain, cold and airflow is a very simple thing.
 
In most cases we'd expect water that isn't being drained to be confined to the aft of the pitot and not end up further up the system. If you have an leak in the pitot tubing upstream of the tube, though, you could possibly see water beyond. A lot of this depends on the exact design and routing of the plumbing. But in a system where you have any significant vertical ascent - as you'd have given the vertical mast section of our pitot - we expect would not support make it to other parts of the system unless there's an additional leak.
 
When life safety is concerned, these things need to move faster than this pitot issue has. If someone had gotten killed...where would Dynon be? I have Dynon in my panel so not hating...just a voice of experience offering some advice. Dynon can and should do better. Running a life test with rain, cold and airflow is a very simple thing.

I could not agree more, as I had been contemplating replacing my Dynon pitot although I can not fully confirm if I have experienced the same issue.

However, I am happy to see Dynon taking a second look at this issue now.
 
Back when I worked for Chrysler R&D...When life safety is concerned, these things need to move faster than this pitot issue has.

I take exception to this implication. The auto industry has a long history of stonewalling on recalls, including safety issues.
 
I take exception to this implication. The auto industry has a long history of stonewalling on recalls, including safety issues.

And Chrysler is not exactly the company I would choose as a top-level safety example...
 
I take exception to this implication. The auto industry has a long history of stonewalling on recalls, including safety issues.

I'm at a loss as to what you could be taking exception to. Are you saying 2+ years to look into a freezing pitot problem is acceptable to you? What part of testing a pitot tube do you think takes that long? A properly trained and experienced engineer can have that life test designed in a day and his tech could have it set up to run within a week. It takes some life testing equipment, but lord I would hope a company producing IFR equipment already has that.

And Chrysler is not exactly the company I would choose as a top-level safety example...

I won't argue that at all. There were a lot of expensive lessons learned along the way to be sure...where legal or bean counters opted to 'wait and see' rather than act on what engineering was telling them. Lessons learned by a company with pockets that deep can save a company like Dynon a lot of heartache....but only if they are paying attention and learn from others mistakes.
 
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Back when I worked for Chrysler R&D, if a known problem took more than a week to diagnose, higher ups started calling. By the end of that month we had a proposed fix, life tested and verified or someone was standing on the carpet discussing his employment. Typically there was one tech and one engineer assigned to the problem though in a case where fire was involved they gave us two techs.

Did they want the answer fast, or did they want the answer to be right?
 
I'm at a loss as to what you could be taking exception to.
The implication that the auto industry, Chrysler particularly, is some model of fast, responsible behavior to problems (within a week!), while Dynon is the model of indifference or incompetence.

Certainly the historical evidence speaks otherwise for the auto industry, but that's not the point of this thread or forum. So what about Dynon? Consider they have probably only a few thousand, at the very most, of these pitot tubes sold and actually being used...they receive a handful of problem reports that "it doesn't read airspeed correctly sometimes". Under what circumstances? Is it reproducible? Is it a random manufacturing defect, or something in the design? If the latter, why isn't it more consistent?

Rare problems are the most difficult problems to diagnose and understand. Dynon now does, and has publicly stated they are working on a fix. Quite a contrast with the auto industry, IMO.
 
I wonder how many pitot's of similar construction in the certified world carry the same issue but have not been identified with it?

Time will tell.
 
I was wondering if any one has heard any thing on this. It has been a while and one would have hoped that they have a solution in place, considering this has been reported a long time ago and Dynon has agreed that there is a problem.
 
Merdad,
This has been and still is a huge priority for us. We have hardware in pilot production and final testing. While this doesn't give us an exact release date yet, we are significantly through the project of this re-design. I'd expect us to have some much more solid timeframe data in the next few weeks.

--Ian Jordan
Chief Systems Architect
Dynon Avionics
 
YES

Stand by for updates. ;)

The problem as I see it is the whole Dynon tube scenario may actually be exposing some certified tubes, just nobody had the data to see the bug.

Dynon have gone to extreme lengths to improve this product, something I doubt many certified probes have ever done.

Hang in there just a bit longer. And stay out of known icing?.as you should. ;)
 
AOA/Pitot freeze

I am also waiting news on this. My wing is still on the stand, so now would be a great time to know the fix. Either repair or replace is my guess. How are we owners going to be notified about it when the solution arrives?
 
fix is out

There are several posts on VAF, or go to the dynonavionic.com web site. Call them, they will send you a repacement. I installed mine today.
 
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