Defective standard aircraft hardware - locking nuts - MS21042

[flyboy1963]

link to service bulletin;

http://www.tc.gc.ca/eng/civilaviati...rvices-referencecentre-casa-2013-04-1781.html

I think I have a couple of these on my aircraft, time to look at them and just replace with fibrlock or castellated I would think.
( no way to establish their age or lot #!)

 

[flion]

If you have them, they are likely in high-temperature areas where only metal lock-nuts are called for. Don't try to swap them for a different type.

 

[Toobuilder]

Remember that in the scheme of things, this is just a limited batch from one of many suppliers. Our company material engineers knew about this issue a year ago and fortunately, of the millions of these nuts we go through, we don't procure from them.

I don't know how easy it would be to track down the source of the nuts that was supplied to Spruce or Van, but there is not a fundamental issue with this type of nut.

 

[David Paule]

If you look at the spec on these nuts, you'll see that they are direct substitutes for the more common types.

Dave

 

[RVbySDI]

Might be a good time to revisit this thread started by Steve Smith a few years ago and revived just the other day:
http://www.vansairforce.com/community/showthread.php?t=42630&highlight=landing+gear+nuts

 

[az_gila]

If you look at the spec on these nuts, you'll see that they are direct substitutes for the more common types.

Dave

Yes... and I believe some builders changed to these nuts globally as a weight saving effort...