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From: peterb@pbear.UUCP
Newsgroups: net.aviation
Subject: Re: Re: China Airlines 747
Message-ID: <87@pbear.UUCP>
Date: Sat, 9-Mar-85 05:54:47 EST
Article-I.D.: pbear.87
Posted: Sat Mar  9 05:54:47 1985
Date-Received: Mon, 11-Mar-85 07:01:14 EST
Lines: 41
Nf-ID: #R:alice:-344200:pbear:26200001:000:2194
Nf-From: pbear!peterb    Mar  8 15:40:00 1985



	Actually you have hit on a point that was all to evident in a 727
mishap a while ago.  I don't remember the airline or the year, but a
mysterious accident occured when for no apparent reason the 727 rolled over
and dived straight down from about 35000-40000 feet shortly after entering
cruise. Another 727 did the same thing a while later and this time they
figured out the reason.

	727's were not originally designed to fly at such high altitudes so
when they do they tend to plow along in a nose up attitude since the thin
air does not create enough lift in a level attitude. this was no real
problem until the fuel crunch, and pilots and airlines realized it. Somebody
came up with an illegal brainstorm: put out 2 degrees of flap and the wing
now generates enough lift to fly level and lower feul consumption, reduce
air time, redice time to cruise, etc. This was great(apparently) but there
was a minor flaw in it.

	On the 727, the flap and slat circuits operate together under one
control. So at 3XX00 feet, in order to put out 2 degree of flap without
having the slats open they pop the circuit breaker to the slats. In the
incidents the bozos doing this either didn't pop one of the breakers or
forgot or whatever. But the end result is rather astonishing. Opening a slat
at about 300-400 knots on a 727 is self-destructive. Apperently one slat
deployed and quickly disintigrated. This caused a highly asymmetric lift
condition(with an entire leading edge gone, there's no choice) which was so
bad that FULL aileron/spoiler deflection could not overcome the imbalance,
and hence the plane barrell rolled over into the ground.

	The FAA inspectors were puzzled when they found that the flaps were
out a little, and that the slats were gone. There was no way to determine of
they were deployed or not, they were just ripped out, actuators and
everything. When they rebuilt the cockpit and examined it, lo and behold one
of the slat breakers was popped. Through some deductive reasoning they
figured the rest.

	The incident with the China 747 sounds a little fishy to me, I
wouldn't be suprised to find that they pulled a real stupid move.

						Peter Barada
						ima!pbear!peterb