Piper Service Bulletin SB1366 - Main Wing Spar Hardware Inspection

Scott Sherer

5/14/2021: Main Wing Spar Hardware Inspection. SB-1366. This affects most PA-28's, 32's, 34's, 44's.

ledwards

Is this at all related to the 2018 lower main wing spar crack issue? The SB does not address the repercussions of the lack of adequate washer to adjacent structure clearance.

ffurbish@cox.net

I noticed the -235s are not listed, is that correct? In spite of that we previously had an eddy current inspection done on the bolts but not sure that addresses the washer issue. Any ideas?

ledwards

Minor, but important editorial correction to my above question:
"Is this at all related to the 2018 lower main wing spar CAP crack issue ?"

Jolo16a

Estimated labor hrs.?

Scott Sherer

Good questions but the SB is the only information that I have a this time. I'll keep my ear to the ground and report anything that I find.

asikora1

Isn't this really about Piper sending out the wrong washers as people were buying new hardware for the Eddy Current test? So some were checked and reassembled with the flat washers and not the rounded end washers.

empannin

Andy, I think it is possible some either substituted the wrong parts or put the washer in upside down during the Eddy current inspection. It also seems when they researched it some may have been incorrect from the factory.

asikora1

Eric, Crazy that the factory workers...who assembled many of them put them on incorrectly but we are all human.

ledwards

I would be surprised if this was only an incidental findings of a wrong part # or lack of installation guidance. It seems too coincidental with respect to the lower wing spar cap crack AD. While I'm not a mechanical engineer, I am an electrical engineer familiar with forces and stresses. But without having access to a stress analysis program and relevant materials information, I can only surmise that having a washer making contact with the structure radius while tightening the bolt to the specified torque would result in a degree of lateral force applied into the structure radius itself as well as into the bolt hole. Piper needs to be asked about the ramifications of such stress, especially over time.

empannin

It is possible they were alarmed as the correct washer was not available and people were at least discussing substituting the similar AN washer (without the radius). Piper should have been proactive in securing the correct parts or even an AD specific parts kit to avoid this and endless scrambling by people looking for hardware.

ledwards

If that was the extent of it, I would expect the SB to limit the inspection to installed replacement washers, not the inspection of virtually the entire fleet.

Sunnywranch

In the service bulletin 1366 it states not to drive out the bolts. In talking with several Piper repair locations the common statement is “ They have never been able to get main spar bolts out without driving the out”. Is there advice/experience that someone could share?