Upcoming AD for many more PA-28 and PA-36 wing spars. 100 anomalies and 6 cracked wings found
- Thread starter xenadu
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Would it be in poor taste to key the mike anytime I hear "Riddle"
pfarber
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pfarber
Just to what most airlines do... fly the AC to Mexico and get it done for a fraction of the cost. Sounds like a new business venture... scarf up affected Pipers, fix them in another country where labor is just as good but 1/10 the cost) and resell them with the AD complied.
Or go E/AB.
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pfarber
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From reading this thread it appears the spars were made 'wrong' and people had to die in order for it to be rectified. This is a manufacturing issue. Not a wear or abuse issue.
Not really. They were designed and produced based on the known usage and application at the time under CAR4. Then the regulations changed with Part 23 which added structural life cycles to the equation due to the known increased usage. If it was a true manufacturing error/issue there wouldn't be 2 separate ADs covering the same part. Perhaps if they included "training and aerial work" in the definition of a "utility" aircraft this may have not ever been an issue?
Yeah...a manufacturing error in 40,000 aircraft has finally showed up in ~10 planes some 60 years later.
Reading some of the bigger organizations that submitted comments. There's 20,000+ hour planes used only for flight training that passed with no issues that had spent their entire lives in Florida.
3 of the spars showing cracks were all close serial number planes from one organization. So perhaps there's something metallurgically amiss in that narrow band of serial numbers. Or perhaps something with that organizations training/maintenance practices that caused premature failure.
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pfarber
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"The spar was cold formed leading to high residual stress near the bolt hole locations."
This wouldn't be a FAR/CAR issue, but a choice in manufacturing, correct? First post does say that newer units were produced differently. not knowing what newer units are it seems that this is purely an engineering choice that even today would not be prohibited.
I cold formed many high stress parts on my airplane. it's a valid practice.
If there is a FAR that ages out spars for part 23 designs can you give a reference?
Piper disputed that finding. In fact the only reason they went with a machined spar is because they were having trouble getting the extrusion.
I believe Cirrus is/was limited to 12,000 hours.
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Drake the Outlaw
All new aircraft designs certified since Part 23's inception (February '65) have a life limit.
luvflyin
Touchdown! Greaser!
Just get it over with. Substitute Cherokee for cop car.
Sure. Below is a brief regulatory revision history of fatigue monitoring, ie., spar aging. You’ll note the wing fatigue monitoring starts with Part 23.572. That section remained in effect until 2017 when Part 23 was rewritten which moved the fatigue monitoring into other FAA guidance documents. Questions?
FYI: there are actually two methods available: assigning a life-limit or use fault-tolerant design principals. Diamond Aircraft uses the latter and has no structural life limits and only structural inspection limits listed in the Airworthiness Limitations Section.
Mooney Fan
Cleared for Takeoff
Let us keep in mind, there are a host of aircraft with airframe limits such as the Tomahawk at 11,000/hrs (has an extension available) Cirrus has a 12,000 airframe limit at which time major inspections and repairs will be required.
Trying to sell an airplane with 8K-10K TT already has its challenges.
And what impact will the proposed AD have on Insurance rates if it comes to fruition as written?
Trying to sell an airplane with 8K-10K TT already has its challenges.
And what impact will the proposed AD have on Insurance rates if it comes to fruition as written?
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Drake the Outlaw
Unless we see more wing failures, I don’t see it as an insurance issue. The AD should make the fleet safer, right? And worn out wings shouldn’t be an insurance claim. At least from my POV.
"Don't go away mad, fellas... Just go away."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…