Incorrect Strap In
A lot has been said, but no one has yet pointed out that the first physical event in the train of events that led to the accident was the fact that on the previous flight the pilot was strapped in with the crotch strap through the SPH. If that had not happened, the SPH would never have got into the unsafe but stable “Position 2” and none of the rest would have happened.
As it happens, on the later flight the pin had legitimately been removed by the time the inadvertent ejection took place. The misplaced pin gave the pilot two opportunities to realise something was wrong and the maintainers a number of opportunities over the weekend to spot it also, but fundamentally it was the SPH being in Position 2 at the start of the later flight that led on to the fateful series of events.
Putting the crotch strap through the SPH is not something I would recommend on any aircraft. The so called MITL testing reported in the SI is very interesting. By some flook with a pilot of Cunningham’s proportions the seat appears not to self eject with one crotch strap thread through the SPH. With a pilot of different proportions or with the same seat in a different aircraft that may not be the case. With a different sized pilot it could well be the case that at some point during a flight with an incorrect crotch strap the pilot would experience an uncommanded ejection leaving an unpiloted aircraft in the middle of a formation with who knows what consequences. Of course in that circumstance (being above 50 kts) the shackle would probably have worked quite correctly.
I think some attention needs to be paid to this. We have heard of mods to the pin housing and to the shackle, but nothing that addresses this incorrect strap-in situation, the very first mistake in the sequence.
EG