The BAe146 used the cabin service doors as the escape route. The standard door structure and locking mechanisms were retained minus the door hinges. Door jettison was aided by a pneumatic ram. To escape the crew dumped cabin pressure via a large butterfly valve in a cabin window, proceeded to the rear service door (in preference to the forward door – in front of the engines), turned the door locks to open, then blew the door clear with a lanyard attached to the door ram-air supply. Egress was completed with a static line parachute drop; bone domes were always worn on high-risk flights.
The 125-800 (900) 1000 developments did consider ejection seats, but this option would have been very complex particularly as there were difficulties with cutting through the top cockpit fuselage skin before the seat could fire. Space-shuttle type pogo sticks via the main cabin door (downward hinged – to go below the wing) were also considered. The compromise solution was a static line parachute drop through a very small fuselage hole directly into the wheel-well; this required the landing gear to be down!
Alf