Originally Posted by
ShyTorque
Looking at the photo evidence in post#983 above, a thought that crossed my mind - would a simple left handed thread on the shaft have prevented this tragedy?
Having recently changed a rear wheel bearing, even my old car has a left handed thread on the left hand side stub axle, to prevent the hub nut coming loose in service.
I'm not sure that it would have done. The smaller nut would have tightened up against its cotter pin and still possibly spun with the pitch rod. It may have still welded itself to the pin carrier. It wouldn't unwind, but could strip the threads or break the pin carrier if the turning force was great enough. If the pin carrier failed and detached from the servo feedback link (as it did on VSKP- according to the report, it was found detached and lying in the TRGB cowling), the resulting loss of TR control would be the same.
Or, the tightening of both nuts on each end may increase the clamping effect on the rod and stop it from spinning, despite the failed bearing. Difficult to say really, and one for the design engineers.