I have done a little homework, courtesy of the excellent Martin Baker website. The ejection seat fitted to the Sea Vixen was a Martin Baker Mk4, the operational minima of which are zero altitude/90 Knots IAS.quicksilver-wsr wrote: ↑Mon May 29, 2017 6:38 pmI'd be surprised if it didn't have zero-zero seats, even though on this occasion they weren't used. The Sea Vixen was withdrawn from squadron service in 1972 while the first test of a zero-zero seat in this country with a human occupant took place as far back as 1961
Interestingly, one of the differences between the Mk4 seat and the first "zero/zero" seat (the Mk7), was the addition of "canopy breakers" On the Mk7, to facilitate ejection through an un-jettisoned canopy.
Maybe I am over thinking this but, if the reason for the 90 Knot minimum is simply the need to get the canopy clear before ejecting, then jettisoning the canopy early, in anticipation of a low speed ejection, would be a very sensible thing to do; it must be painful trying to eject through a canopy in a seat that wasn't designed for it....
Nigel, this has sparked my interest in the subject. Thank you for your reading recommendation; I have just ordered a copy.