BI8
You appear to be rather out of date on your T4 tech exam. The hatch is not frangible, it is solid, and jettisoned by explosive bolts. This requires no separate action, provided that the hatch safety switch is made live; the hatch is then jettisoned by the intial handle pull. As it departs, it withdraws a restrictor from the seat, allowing the seat gun to fire in sequence as the pull is continued. The pilots canopy is indeed jettisoned, but again this is automatic once the canopy/snatch master switch is set to live (as is firing of the snatch unit to sever and withdraw the control columns).
None of this, of course, tells us anything about thursday's tragic events. However, it is evident from the photographs that:
The Navigator's hatch has jettisoned and the seat has fired (I know - talk about stating the bleedin' obvious).
The pilots' canopy has jettisoned.
Both pilots' seats have fired.
Can't vouch for the snatch unit, but the BoI will know by now.
There is no command ejection system, each takes his turn in sequence by his own actions. It is recommended that the pilots avoid, if possible, simultaneous ejection. Not that you have too much time to worry about the niceties.
Posted to head off more uninformed speculation. Forgive me, but as a former colleague of one of the guys and an acquaintance of the other two, I am finding it difficult to keep my temper. Yes, of course we all want to know - but we are achieving nothing useful here.
Ginseng