Re: B757 Engine Compressor Stalls over US

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         16 Jul 96 13:51:46 
References:   1
Followups:    1
Next article
View raw article
  or MIME structure

>Does anyone have details on engine compressor stall forcing landing from
>Miaml to Denver on United 757 around 14 July?  ...
>Will this disrupt the ETOPS rating of the bird as the engine tests were
>accelerated and extrapolated?

Are you talking about a 757 or a 777?  MIA-DEN on UA would probably be
a 757, but I'm not aware of any "accelerated and extrapolated" ETOPS
testing of the 757.

Note -- if it was a 757, odds are it was not an ETOPS aircraft since
UA only has between five and ten ETOPS 757s.  (Ten originally, but
some were taken out of the ETOPS program, at least for a while.)  Even
if it's a non-ETOPS plane, it would influence the ETOPS rating, since
the statistics are not based solely on ETOPS aircraft.  When I was on
a UA 747-400 that suffered a compressor stall, the pilots had to fill
out all sorts of extra paperwork for the in-flight engine shutdown,
because the PW4056 engine is similar enough to the PW4060 used by UA
on their ETOPS-rated 767-322(ER)s.

>My understanding was that stalls continued for some time and landing
>was required due to controllability fatigue in cockpit.

I don't think the crew would leave the engine running after a
compressor stall, certainly not if the stalls continued.  Once an
engine is shutdown, they must land at the nearest available field.
Fatigue is not an issue in that decision, though no doubt the pilots
would be fatigued after such an episode.  The ability to fly the
plane with one engine windmilling should have been thoroughly
evaluated during the basic certification process, never mind ETOPS.

--
Karl Swartz	|Home	kls@chicago.com
		|Work	kls@netapp.com
		|WWW	http://www.chicago.com/~kls/
Moderator of sci.aeronautics.airliners -- Unix/network work pays the bills