These things:
are currently issued to certain AT crews and are hung off the back of the individual seats. They obviously can't be worn whilst in the seat and are intended to be grabbed as one hurtles past, fleeing the looming conflagration or whatever. "Dismounted" (
) they're mildly hopeless when worn over one's body armour. There is a UK manufactured combined system that I believe rotary types currently use. There are moves afoot to issue to us - it's opposed by our SERE chaps and those of us that have seen it/attempted to use it but I think any such opposition merely speeds up the acquistion process.
Well designed and though out combined armour/modular systems do exist (Eagle Industries) and indeed are in use in vast numbers by elements of the USAF.
I believe the opposition to these is based on the lack of retired RAF air ranks on the board of Eagle Industries Ltd. Hush my cynical mouth....