Upcoming AD for many more PA-28 and PA-36 wing spars. 100 anomalies and 6 cracked wings found

Walboy said:
How would one phrase a comment in support of Piper to be effective?
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From my experience, it can be as simple or as complex as you want. Since Piper has taken the lead a simple one line agreement to their letter will suffice. Or your example as well. Its the numbers of people commenting in the same context that matters.
 
The comment period for both ADs ends on 11/7/2024.

So far there are 8 comments on AD-2024-00033-A including Piper's and 9 comments on AD-2024-00008-A.
 
Tarheelpilot said:
Yeah. They don’t give a **** about your ability to afford aviation any more than you care about their retirement.
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I wonder if we should hope they don’t read forums like this and get some idea of how much pilots who haven’t met them apparently despise them; their quite normal human reaction would probably not be to our benefit. Hopefully they’re bigger/better than that…;)
 
Walboy said:
How would one phrase a comment in support of Piper to be effective?

"I am an owner of a Piper aircraft subject to the proposed AD and object to the FAA's proposal. I have read Piper's response to the proposed AD and feel satisfied that their expert analysis and experience with a previous similar AD shows that the proposed AD is not only unnecessary, but potentially more harmful than doing nothing at all."

Or something similar?

I think when it comes to comments from lay persons, the less verbose, the better.
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Try reminding FAA that if the AD causes more failure, they can get sued.
 
How does one go about submitting commentary to the FAA for this particular rule?
 
ArrowFlyer86 said:
How does one go about submitting commentary to the FAA for this particular rule?
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If you go to the links I posted in post #3, at the top of the page is a green button that says "post a public comment".
 
If I were a Piper owner, I would at least send a comment about my local/regional shop rate.

10 minutes of your time divided by the potential market value savings is a LOT of dollars per hour :)
 
I posted a comment. Gist of it was doing the inspections has a risk of damage as noted in the Docket, $85 is way too low for a labor rate and Piper's comment was very fact based and should be considered as part of the final rule making.
 
Llewtrah381 said:
I wonder if we should hope they don’t read forums like this and get some idea of how much pilots who haven’t met them apparently despise them; their quite normal human reaction would probably not be to our benefit. Hopefully they’re bigger/better than that…;)
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I find myself wondering if the FAA and other federal employees have a forum somewhere….probably best to drop that line of thought.
 
ArrowFlyer86 said:
Damn! Piper really came out swinging with their response. To my great surprise - Piper actually seems to be sticking their neck out here to defend the fleet of planes from 50y ago! A lot of gems buried in there.

FAA can't be happy to read lines like:
"[FAA] mis-characterize the extent of collaboration between Piper and the FAA... While it is true that the FAA and Piper worked together to determine an inspection program, the FAA rejected the proposals put forth by Piper. Throughout this process, Piper Aircraft has consistently supported the FAA's efforts while formulating a conservative corrective action plan. The FAA requested extensive data and analysis, and Piper delivered countless pages of comprehensive documentation, most of which appears to have gone unused by the FAA"

I think one of the best points I read in there was their refuting the legitimacy of basing the inspection/spar policy based on 1 single, solitary plane.
"It is not appropriate, nor is it rational to base inspection times on a single airplane which will dictate the inspection program for the entire fleet of aircraft in the field"

I also enjoyed a number of their other points based in fact:
- Sytematically looking at each aircraft that had cracks. Pointing out history of heavy modifications/bad landings/ and in 1 case a hangar having previously collapsed on the plane!
- The same reason they withdrew the AD in the 1980s is valid today (maintenance fatigue + cost). Quote: "On May 22, 1989, theFAA made the justified decision to rescind the AD, citing that performing the inspections could damagethe wing spar bolt holes resulting in premature fatigue and failure of the wing spar, and therefore thesafety benefits did not justify the inspection costs."
- $141/hr is a much more realistic shop rate than the FAA's assumed $85/hr
- Why Group1 has a lower starting CSH than Group2 despite Group2 having higher operational loads/stresses
- That CSH could exceed TIS with the FAA calculation, which results in non-sense answer

It all just sort of makes a case that this proposed rule was assembled haphazardly and without a lot of logic, and definitely not in lockstep agreement with the manufacturer.
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I was also impressed by their described statistical analysis. Some may recall that I did some ad-hoc analysis of this issue a few months back, but based on their reply I am satisfied that Piper worked with the right experts to perform a high-quality analysis of failure rates. That the FAA ignored this analysis and picked numbers based on a single sample doesn't surprise me at all given the sins in the SAIB.
 
Comments Submitted! (to proposed AD, Docket No. FAA-2024-2143)

I’m a 1967 PA28140 driver with +/-4200 TIS, so I’ve escaped mention in AD 2020-26-16 and the proposed AD Docket No FAA-2024-2142. However, the proposed AD 2024-2143 has me “in the system.” Will be quite a while (probably not in my lifetime) until the Cherokee hits 12,000 TIS, but I do have issues with the facts, logic and justification for the proposed AD. No doubt, fatigue cracks in the spar is a serious issue, but I’m not convinced if this is a big problem or a little problem. Piper, in its response to comments (to FAA-2024-2142) did a very good job of laying out the background, history and analysis of the spar cracking. Was not aware that this issue arose back in 1987, and the FAA rescinded the proposed AD. It is more than apparent that the aircraft with confirmed spar fatigue cracks were high time, high stress environments. Did chuckle about the one that had a hanger collapse on it.

The prudent pilot part of my brain says.. hey, it is worthwhile to find out now if I do have spar cracks, highly unlikely but the consequence of a cracked spar is pretty much fatal. My analytical brain says… hey wait a minute, aren’t you opening a can of worms executing a relatively complex and expensive process when in all likeyhood the spar is just fine (and you really don’t have to do this). Part of my dilemma involves some of the data in the proposed AD which were very confusing to me. The FAA mentions that they received >2,800 Eddy Current Inspection (ECI) reports, of which >100 reported “Indications”. There is no information on how many of the >100 were resolved or how many actually had spar cracking. The FAA also mentions that Piper later conducted a study of 24 main wing spars of which 20 had ECI “indications” and of those, 3 had fatigue cracks. It is not clear whether the 24 in the Piper study were part of the 2,800 mentioned earlier or were a completely separate group. If it’s the later, that is an extremely high failure rate. If it’s the former, seems as though I have a 1 in 28 chance of getting an “indication” possibly resulting in wing removal for further testing. The proposed AD also mentions that 6 spar cracks were found (as part of the >2800 ECI reports) but it is not clear that an ECI would have found them, possibly they were found when the wings were pulled?

I have zero real world experience with conducting an ECI. Reading through Piper Service Bulletin 1412, the process is not trivial and seems to me, to have pretty low confidence that doing an ECI alone will identify a spar crack, or more importantly, indicate that the spar is fine and can be returned to service. Add to that, is the fact (as acknowledged by the FAA) that doing the ECI improperly can cause damage that could led to a formerly sound spar to develop a fatigue crack.

Is there any additional data out there concerning the confidence level or results of the ECI in determining if a spar has fatigue cracks (or the spar is just fine)? I’d be happy to spend some dollars on a test… IF there was a high confidence level that would resolve the issue. The way the Service Bulletin reads (at least to me) is that if I get an “indication” (a 1 in 28 chance? -or- a 20 out of 24 chance?) I get to clean the area and redo the ECI, if the “indication” is still there, looks like I’m pulling a wing to resolve the issue. Some real world experience would be useful.
 
Gary said:
I’m a 1967 PA28140 driver with +/-4200 TIS, so I’ve escaped mention in AD 2020-26-16 and the proposed AD Docket No FAA-2024-2142. However, the proposed AD 2024-2143 has me “in the system.” Will be quite a while (probably not in my lifetime) until the Cherokee hits 12,000 TIS, but I do have issues with the facts, logic and justification for the proposed AD. No doubt, fatigue cracks in the spar is a serious issue, but I’m not convinced if this is a big problem or a little problem.
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Perhaps some more context between the ADs will help. The only reason for AD-2143 is these applicable aircraft share a common core spar with AD 2020-26-16 or AD-2142 applicable aircraft. There is no direct link, by aircraft model, to the fatigue failures mentioned in those latter ADs. And the common trait of those core spars is a cold-bend manufacture process at the spar mount hole area.

So for your “prudent pilot” part, it may help to address those AD differences than what they may have in common between them. Which is also the same reasons why there are 2 separate ADs and inspection requirements.

For your “analytical” side, perhaps see where you stand as an owner on a scale of “involvement” for lack of a better term. On one side, you have owners that follow only the FAA minimums (Part D annual, ADs, etc.) and on the other end you have owners that follow all FAA and OEM requirements (OEM book annuals, all OEM bulletins, etc.)

So depending where you sit on that scale, it may give you a better overall view at a higher level vs a “tunnel-vision” view on a very public topic. I’ve found that sometimes when you take a step back and see the whole picture it tends to offer a better perspective. Or at least generate more direct questions to your specific situation.

Gary said:
I have zero real world experience with conducting an ECI. Reading through Piper Service Bulletin 1412, the process is not trivial and seems to me, to have pretty low confidence that doing an ECI alone will identify a spar crack, or more importantly, indicate that the spar is fine and can be returned to service.
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Eddy current is a proven NDT inspection process that is used throughout the aviation industry on a daily basis. It works. However, as with any inspection process if its not performed correctly, the results may be skewed or invalid. This is no different than performing a visual inspection without a bright light and mirror.

And SB1412 provides the necessary details to perform that inspection down to the requirements to minimize damage during the performance of the inspection. So if you decide to have the spar inspection done, the key with any maintenance is to engage people who know and understand the work at hand and give you the confidence they can perform that work properly in accordance with the applicable guidance. And for reference, this is the same reply I've given people who had asked similar questions on their aircraft for this topic.
 
I cant imagine getting news like this. I gotta get away from certified and finish my kit. Might be some good deals on low-time lycomings soon?
 
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