Re: ETOPS Question

Date:         16 Sep 97 02:35:24 
From:         jf mezei <"[non-spam]jfmezei"@videotron.ca>
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C. Marin Faure wrote:
> limit.  After several bad crashes of twin-engine piston airliners in the
> 1950s after they lost one engine and burned up the other one trying to
> reach an airport,

On modern jetliners, if one engine fails during cruise, is the remaining
engine really used to the max ? Or can the plane continue to fly
safely with the remaining engine well below its maximum thrust at a
regime
that is sustainable "forever" ?

Or is there still a need to limit single-engine operations to a certain
length because the remaining engine, being tested to its limit, really
has a higher risk of failure ?

> safe flight after the in-flight shutdown of an engine.  The fire
> supression system must be able to keep a lower hold cargo fire from
> spreading for 180 minutes, the backup electrical and hydraulic systems
> must be able to keep the airplane's control systems functioning for 180
> minutes, the battery(s) must be able to keep certain critical
> communication and navigation systems functioning for 180 minutes, and so
> forth.

Are these requirements any different from 3 or 4 engined jets ?
Considering the
history of fires which consume airplanes in the matter of minutes, if
you can survive 180 minutes after a fire has been declared, doesn't this
mean that the fire was totally extinguished and hence, you could
continue forever ?

Also, for the backup electrical/hydraulic systems, if one engine fails,
won't all these systems continue to operate safely from the remaining
engine ? Or would they  really be put to the test with significantly
higher likelyhood of failure ?

Now, if the remaining engine fails, is it not rather pointless to
require the true backup electrical systems (battery and prop-turbine) to
operate for 180 minutes ?
bAren't we talking more like 15-20 minutes before the plane becomes a
boat ?