In the earlier days of flying, when aircraft speeds were low, it was a relatively easy matter to resort to a parachute to escape from an aircraft in trouble but, as aircraft speeds increased, escape by means of a parachute was more a matter of good fortune than of personal effort. Early in 1944, with the introduction of jet aircraft into the Royal Air Force, it became apparent that some assisted means of escape would have to be provided to enable air crews to escape from fast jet aircraft in an emergency. It was early in 1944, therefore, that I was invited by the Ministry of Aircraft Production to investigate the practicability of providing, in fighter aircraft, a means of safe escape for the pilot in abandoning the aircraft.