Originally Posted by
Thruster763
Follow on to my response to JamiaJoe above. I said there should not be significant loads on the quides, pins or upper lock-out bolts.
Unless of course, as I suggested yesterday, the stops were not correctly adjusted. This would put pressurisation loads on the guide / pin possibly resulting in low cycle fatique failure of the guide / pin/ bolt and loss of the plug.
I've seen no comment on this theory.
Certainly possible as this appears to be an installation / maintenance cause - presumably the examination of the plug and its guide tracks will clarify this. Whilst thinking about this theory I looked again at the detailed photo of the guide track and stop bolt in post #303 and two associated possibilities occurred to me. I think the use of a castellated nut on the stop bolt is an active design choice as it seems likely that to avoid damaging the guide track the nut is not tightened to any significant degree and the nut is prevented from loosening by the castellations and split pin. IF this is the case then possibly:-
- the split pin was not present or fell out, the nut loosened and the bolt disengaged
- or
- the bolt was overtightened and damaged the guide track such that the engagement with the guide roller was not effective.
Thoughts?