Re: Plane crashes and other accidents

Michael Lorrey (
Thu, 16 Apr 1998 20:03:36 -0400

EvMick wrote:

> In a message dated 4/16/98 10:50:52 AM Central Daylight Time,
> writes:
> << I've seen a serious proposal for a system which could bring down an
> entire 747 by parachute in a serious inflight emergency (or individual
> pieces if the plane should partially break up in flight). The problem is
> again cost and mass; AFAIR it requires fourteen large parachutes fitted
> to various parts of the plane.
> >>
> I seem to recall some time ago that one of the combat aircraft (?) was fitted
> with a system whereby the entire crew compartment ejected as a whole with
> built in parachutes...what would be the problem in having such a concept for
> commercial passenger aircraft? That is: in the event of a "crash and burn"
> emergency the pilot could eject the passenger compartment. It then descending
> on it's own automatically deployed chutes. Since said compartment would be
> much lighter than the entire airframe it would possible require less chutes.

This was used on the F-111 and the F/B-111, as well as the EF-111, obviously. The
maintenance of the capsule was equal to around 1/4 to 1/3 that of the rest of the
airplane, increased its weight (and therefore decreased its range and performance,
and increased its cost) The capsule pressurized at a level equal to 8500 feet, and
could be entirely ejected rapidly with a built in rocket motor, even while on the
ground. It had a set of parachutes equal in size to those used on the Apollo space
capsule, as well as a rapidly deployed attenuation bag that inflated just prior to
touchdown. In the event of an ejection in flight at low altitudes, such as those
experienced by commercial airliners during takeoffs and landing approaches, the
capsule hits the ground rather hard with horizontal velocity retained, frequently
causing serious back injury to the occupants.

This concept is not used in any civil aircraft of any type for the simple reason
that its too damn expensive to own and maintain.

> Of course...the redesign of the airframe might negate any saving.
> And the pilots might complain...but presumably they might be trained in the
> use of individual parachutes...or have a seperate system for the pilot
> compartment.

There are currently parachute retreival systems available for aircraft of up to
2-6 seater private types, like a Cessna 182 or a Piper. They deploy the chute with
a small rocket, and give a rather staid ride down for the entier aircraft.

Using such systems obviously is a matter of mass and economics. Considering that
air travel is safer than sitting on your own toilet, its rather obvious why there
are no commercial airliners that have large parachutes and attenuation bags to
retreive an entire plane. The long term costs of maintaining and lugging around
all of that unproductive mass far exceed what customers are apparently willing to
pay for the marginal increased safety.

   Michael Lorrey
------------------------------------------------------------ Inventor of the Lorrey Drive
MikeySoft: Graphic Design/Animation/Publishing/Engineering
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