FAA hardware SAIB HQ-14-16

[Traash]

Recently the FAA published SAIB HQ-14-16 relating to non-conforming standard fasteners, notably MS 21042 nuts. A portion of this notice is pictured here:

You can access the full SAIB via the FAA's website.

The nut mentioned is pictured here as a copy of the Aircraft Spruce page with an actual nut next to the drawing. The lower MS21042 is the problem child. The upper AN363 is another style of all metal lock-nut.

I have personally had two of these nuts fail in my engine compartment. One on the linkage to my mixture control, the other on my exhaust hangers. I have replaced all (numerous) of my MS21042's with AN363's for peace of mind. At the least I think it prudent to avoid use of the problem nuts in critical areas where a single failure could result in an unairworthy condition (i.e. flight or enigine control linkages).

 

[aerhed]

Hah. I posted several years ago that these were not real MS21042 nuts. I got blown off.

 

[David Paule]

Worth checking.

If you've got a good set of them, they can save roughly a pound per airplane.

Dave

 

[paul mosher]

traceability

This is the reason feds require traceability of aircraft parts.

 

[RV6_flyer]

I have them all over my RV-6. Been flying with most of them for over 16.5-years. The batch I have in stock must be over 20-years old.

 

[digidocs]

Traash,

Thanks for sharing this SAIB. Can you share your supplier and the approximate date of purchase of the failed nuts? Also, were they the cad plate colored or darker colored ones?

Thanks for sharing,
David Carr

 

[Aircraft Spruce Info]

MS21042 / SAIB HQ-14-16

We noticed the postings regarding MS21042 nuts which were accompanied by a photo of the Aircraft Spruce catalog page featuring stop nuts. We have reviewed SAIB HQ-14-16 and have confirmed with our hardware supplier that none of the questionable MS21042 nuts came from their supplier, so none were shipped to Aircraft Spruce. Insuring that all aircraft hardware is authentic and produced to meet specifications is of vital importance. Aircraft Spruce obtains all hardware from highly reputable sources who provide full traceability and certification that the hardware meets all applicable standards. Please contact Aircraft Spruce at any time for further information on our AN/MS/NAS hardware.

Aircraft Spruce & Specialty Co.
Customer Service Dept.
(951)372-9555
email: [email protected]

 

[David Paule]

Thanks for letting us know - that's great news for me; I've got a ship's set of them from you for my RV-3B.

Dave