Aircraft Deceleration Devices

"SteveM8597" wrote in message
...
A non flying software engineer friend of mine insistes it is poossible to
put
devices on a plane to make it safer by impacting the ground at a low
velocity
after loss of control or catastrophic failure, or to be able to manuever
to
miss an obstacle when impact is imminent. These devices would include
retrorockets, large recovery chutes, airbrake type control surfaces,
warpable
wings, and software on airplanes. Ballistic recovery systems have had
successes on light planes and ultralights Otherwise, I have told him that
the
above have been proven to be impractical and even dangerous. He insists
that
technology is there that would allow either an out of control or powerless
heavy to eiher recover or hit the ground softly enough that it would be
survivable. I've got 34 years in the business and a degree in aero
engineering
but he seems to think I am just being negative.

Any comments or knowledge of potential technolgy I can feed his pipe
dreasm
with?



It may well be technically possible but the challenge is to
develop a system at affordable cost that doesnt impose
unreasonable performance constraints and that performs
reliably enough to decrease risks.

For example consider the case of a ballistic recovery system
designed to allow an aircraft to 'parachute' to safety. The number
of situations in which such a system would have helped seems
small given that must airliner accidents happen at landing
or takeoff or involve controlled flight into terrain rather
than a technical failure. The result of such a system deploying
accidentally mid Atlantic would be unfortunate so it must be
rather more reliable than the aircraft itself, a non trivial task
when one considers how rarely aircraft have crashed due
to techical faults.

Keith