Re: Reuters Story On Peru Boeing 757 Crash and DR

From:         radagast@DELETE_THIS.worldnet.att.net (Radagast the Brown)
Organization: The White Council
Date:         06 Nov 96 05:12:37 
References:   1 2 3 4
Followups:    1
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On 05 Nov 96 04:14:01 , eaustin@islandnet.com (Edward Austin MSc) wrote:

>On 5 Oct 1996 03:33:07 GMT, rickydik@ix.netcom.com(RD Rick) wrote:
>
>>In <533vhb$3rm8@acs2.acs.ucalgary.ca> bauwens@acs.ucalgary.ca (Luc
>>Bauwens) writes:
>
>>>Again, misleading/sloppy/dishonest job by the press?
>>>
>>>No matter how hard a bunch of prejudiced Germans tried to
>>>ascribe the responsibility to the Turkish crew, I thought
>>>it had been generally recognized that the key factor in the
>>>accident was the conflicting reactions of two computers or
>>>software to a plugged pitot tube?
>>>
>>>One of them producing an (incorrect) overspeed warning while the
>>>other, a stall warning.  Faced with 50/50 odds, the pilots picked
>>>the wrong bet...

The odds are *not* 50/50.
There's a standby attitude instrument with an independent power source in
case the engine driven generators quit.  There's also an alternate air
source for the air data computers (but on most airplanes, it must be
selected manually).  Any trained airline crew faced with conflicting
primary displays would automatically check that.
Whether *those* was also affected by the plugged pitots, or whether this
crew failed to use it, remains for the professional accident investigators
to determine.  If there's a cvr transcript out yet, I haven't seen it.
But I know of at least one B727 that lost all of its airspeed indicators
upon rotation (the connections broke; the weather was RVR 600, and rotten
all the way to destination).  The crew just flew attitude and throttle
position all the way to destination.  That's a little more difficult with
the computerized airplanes, because the pilots no longer have a good feel
for what the throttle position or fuel flow should be, but I imagine it
could be done.

>Not too different from another crash initially blamed on the Turkish
>crew by the American press, that of the THY DC-10 back in March '74.
>This crash initially ascribed to pilot error turned out to be faulty
>design of the cargo door latching mechanism. Mc D-D (and the American
>press)  implying the crew being "Turkish" was somehow to blame.

Maybe.  I didn't know that that one had been blamed on the crew.  But the
Aero Peru crew should have caught taped-up static ports on their preflight
if that is, indeed, determined to be the cause of the crash.

R