Re: hydraulic problems with DC-10's??

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works
Date:         Wed, 25 Nov 1992 00:40:06 GMT
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In article <airliners.1992.30@ohare.Chicago.COM> weiss@curtiss.SEAS.UCLA.EDU (Michael Weiss) writes:
>I have a hard time believing that an intact hydraulic system would have
>prevented AA191 from crashing.  Let's face it, a wing-mounted engine falling
>off produces such a rediculous unbalance that even full aileron wouldn't be
>able to counter it.

I don't see that ailerons have much to do with it -- the biggest
effect would be a substantial yaw, which would require rudder input.

In any case, start believing.  A United 747 (N4713U, now N4724U)
operating a HNL-SYD flight on Feb. 23, 1989 lost both engines on the
right side due to debris ingestion after a cargo hatch failed.  They
dumped fuel and limped back to Honolulu, well over an hour's flying
time.

Having lots of altitude and airspeed to work with is certainly quite
helpful, but isn't a requirement.  A few years ago a Piedmont 737-200
lost #2 immediately after takeoff from O'Hare.  The pilots promptly
declared an emergency, turned around, and landed several minutes later
on another runway.  They didn't even realize that the engine had
litterally fallen off until the got off he plane and looked.

Getting back to AA 191, what really killed AA 191 was a stall of the
left wing after the uncommanded retraction of the flaps on that side.
Even this was recoverable had the pilots known that their stall speed
was suddenly higher -- alas, McDonnell-Douglas didn't bother with any
redundancy for the flap retraction warning and that happened to be
powered by the engine that fell off.  In simulator tests after the
crash, every pilot crashed when confronted with the same scenario.
When given this indicator, and thus some indication of what was going
on, every pilot managed to maintain control of the aircraft.

An engine separation, while certainly not a normal event, should not
be a fatal event, and indeed the certification process requires some
consideration of an engine separation.

-- 
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