Re: in-flight engine shutdown / antiquated ATC equip

From:         geohull@ditell.com (George Hull)
Organization: DirecTell L.C. - Park City, UT. - 1.801.647.0214
Date:         22 Jun 95 03:07:31 
References:   1 2 3
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> > >The shut-down of one engine meant the loss of an air conditioning unit,
> > >and the remaining unit overheated.
> >
> > The crew should have been able to operate the other pack by
> > cross-bleeding.
>
> Yes but the other engine may not have been able operate the other pack at
> that altitude as well as power the aeroplane whilst remaining within its
> operating parameters.  They may have been limited by egt or some other
> factor.  The air that the engine needed to supply the other pack and
> maintain pressurisation at that altitude may have been too much for the
> engine limits.

The possibility of the loss of an engine also carries with it the systems
requirements necessary to safely complete the flight.  A driftdown
maneuver following the loss of an engine will require pressurization as
well as electric and hydraulic systems.  That's all taken into
consideration during ETOPS engineering and operations.  Overwater aircraft
also are required to have an APU which can be started in flight (starting
it is one of the frequent inflight checks required on ETOPS flights) and
it can supply bleed air and electrics, too.  It would be folly to expect
that the loss of an engine would results in the loss of the critical
systems.  There have been many unscheduled inflight shutdowns and systems
failures during ETOPS operations . . but no passengers floating in the
North Atlantic, yet.  At our airline the ETOPS aircraft leave the U.S. in
pristine mechanical condition and they're watched very carefully.
Anything less would result in problems with scheduling, maintenance, or
safety.  It's just good business.

George