Piper PA-28 wing falls off

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StressMerchant
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Re: Piper PA-28 wing falls off

Unread post by StressMerchant » Wed May 23, 2018 2:35 pm

I won't argue that the design is poor, and that Piper did not make repair work easy. The presence of structural members that cannot be inspected is a worry.

I have a suspicion that the initiating event for this failure was either at production or a major maintenance episode.

FWIW staggering of bolts is not necessarily the answer. The bolts and rivets need to be at the right place, and under the right loads, to effectively transfer the load through the structure.
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Re: Piper PA-28 wing falls off

Unread post by RogerRoger » Tue May 29, 2018 8:32 pm



I have no horse in this race but this is interesting :shock:
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Re: Piper PA-28 wing falls off

Unread post by Ugly Duckling » Fri Sep 06, 2019 12:42 am

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Re: Piper PA-28 wing falls off

Unread post by Surge » Fri Sep 06, 2019 3:17 am

Ugly Duckling wrote:
Fri Sep 06, 2019 12:42 am
NTSB report
https://www.ntsb.gov/_layouts/ntsb.avia ... 120&akey=1

Sheew! There are some very clever people in this world.

The problem was also discovered on another PA-28R-201 (N104ER) operated by ERAU so this is not a once off problem. It likely saved some lives in the process.
The USAF estimated that the sister airplane's wing, with a fatigue crack measured at 0.18 inch, was less than 2,000 hours from failure.
It doesn't look like a visual inspection would have picked up the problem. Certainly not with the wings in place. :?
The fatigue crack on bolt hole LC-1 on sister aircraft N104ER was not visible using optical magnification.
It was only detected when the the wings were removed and a "level II certified ultrasonic testing inspector" used a HFEC surface probe for testing.
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Re: Piper PA-28 wing falls off

Unread post by kudu177 » Fri Sep 06, 2019 7:49 am

Volo wrote:
Thu Apr 05, 2018 10:02 am
I seem to remember something about mainspar corrosion being a problem on older PA 28's - would kind of explain the complete detachment of a wing !!
True. About the time i was doing my PPL in George (Dec 1988),a story in one of the US flying mags that we had in the clubhouse about Cherokee 140 main spar failures got everybody’s attention.

Easpecially since the school aircraft had spent a lot of time in a coastal environment.
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Re: Piper PA-28 wing falls off

Unread post by dollar » Fri Sep 06, 2019 10:55 am

Wow. I watched the video and must say that it’s a pretty simple attachment method. And cheap to make I bet. It obviously works though - wings don’t routinely fall off?

So the forward attachment bears most of the load stress. The rear attachment the lateral stress - backwards and forwards. The rear all held together by one bolt?

Looks like it’s operating close to its limits - bit of undetected fatigue or damage and bye bye wing.
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Re: Piper PA-28 wing falls off

Unread post by ddevos » Fri Sep 06, 2019 4:11 pm

dollar wrote:
Fri Sep 06, 2019 10:55 am
So the forward attachment bears most of the load stress. The rear attachment the lateral stress - backwards and forwards. The rear all held together by one bolt?
Even Impala jets have one bolt holding the rear spar. I once had the unenviable task of cutting a rear spar off with a hacksaw because the bolt was bent inside the joint and we just couldn't get it out where the aircraft was lying on its belly in soft sand. That was in 49 degrees of heat as well! Not fun...
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Re: Piper PA-28 wing falls off

Unread post by heisan » Sat Sep 07, 2019 1:02 am

dollar wrote:
Fri Sep 06, 2019 10:55 am
Looks like it’s operating close to its limits - bit of undetected fatigue or damage and bye bye wing.
Every single part of every aircraft is operating close to its limits (usually only 1.5x safety margin). Could build them stronger, but then they would be too heavy to fly ;).
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