Re: 2 engines vs 4 engines planes

From:         ditka!sgiblab!uunet.UU.NET!ucsd!!pete (Pete Coe)
Organization: Rational
Date:         30 Oct 93 22:33:47 PDT
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  or MIME structure (Dietmar Hanke) writes:

>Is it possible to fly a B-747 when 2 of the 4 engines failed? Was it even 
>possible when both engines on one wing woudn't work anymore?

Hey! 747's have been known to fly with no engines.  There was that British
Airways 747 that flew into a volcanic ash cloud, and for 30 minutes or so
became the world's heaviest glider.   

That incident, and others (e.g. Eastern Tristar losing all engines due to 
incorrect maintenance), leads me to think that as far as engines go, two 
is never enough.  The statisticians can argue the point as long as they 
like, but the fact is that more has to be safer.  I doubt that the two
above incidents would be covered by ETOPS regulations, because they
were not a fault of the engines, or airframe design.  But in both
cases, the flight crew only managed to save the day because they
could get _some_ power from _all_ the engines (as opposed to all 
the power from one of the engines). If either had been a twin, we
would have lost passengers to another 'unfortunate incident'.

At the time of the BA 747's little problem, my father was project manager
for 747's at BA.  Up to that incident BA had been considering removing the
air turbines from the planes as they were not used.  At least that idea
got canned.  Incidentally, that plane has never been the same since.

Sorry about the rambling.  I just think twin engined aircraft are a bad
idea, and while I consider them acceptable for short/medium haul routes,
I think that Long over water ones are just an accident waiting to happen.

The 777 gives me nightmares.  How many people do we have to kill before
the airlines stop this crazy quest.  Although I am myself a professional
in the aviation industry, I consider myself to be well informed.  I have
also clocked up well over 500,000 miles in the air.  In that time I have
had one engine lost to a bird strike (Conway), two in flight precautionary
shut down's (RB211's), and one aborted take off (RB211 again) due to engine
malfunction.  I don't know how atypical these numbers are, but the incidents
have been frequent enough for me to actively avoid the 767 on trans-atlantic
flights.  Now my statistics all end up being British engines, but that is 
because I usually fly B.A.  I am sure the American manufacturer's figures
will be equivalent.

Rant mode off.


-- Pete Coe
-- Rational
-- Object-Oriented Products