[sacnoradhq]

It's surprising most rotor mast designs don't include a nested secondary nut and don't use lockwire.

In Japan, motorcycle racing requires lockwire on almost everything. It's a shame helicopter safety engineering generally doesn't meet this basic standard. Although, in fairness, relying on a single spinny thing without an all operational envelope survival passive glide capability is itself inherently dangerous.

[MarkMarine]

The Jesus nut on a Huey and a cobra both include a secondary lock (looked like a single gear tooth) secured by a bolt and lock wire.

The nut was torqued to 3000 ft-lb so this was kind of superfluous. But it does show that the nut was torqued, witnessed, and wired.

[bityard]

Literally the second sentence says that the the Jesus nut is secured by a retaining pin.

[dtgriscom]

... maybe because lockwire wouldn't help in this situation?