Re: Details on recent PW-4xxx engine problems?

From:         tristar500@aol.com (TriStar500)
Organization: America Online, Inc. (1-800-827-6364)
Date:         22 Jul 94 12:44:03 
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In article <airliners.1994.1455@ohare.Chicago.COM>, kls@ohare.Chicago.COM
(Karl Swartz) writes:

>The only problem I'm aware of with the PW4060 on the 767 was the in-
>flight reverser deployment which led to the Lauda Air crash outside
>Bangkok. 

The engines also vibrate so bad that clamps and wiring harnesses are
self-destructing. This is on 767-300ER and A-310-300s. The ETOPs airplanes
are subject to a 'hardware' check almost everynight to look for damaged
clamps, hardware and wiring caused by the vibration.

RE: inflight deployment of thrust reversers. 
The fix for this was the installation of 'sync locks'. These are
mechanical locks that prevent the TR sleeves from moving when they are not
commanded. In the old system, (prior to the sync locks) if an uncommanded
deployment of the reverser was sensed, hydraulic pressure was
automatically routed to the stow side of the thrust reverser actuators.
This would have been accompanied by the 'REV ISLN' EICAS message, which is
what the Lauda Air crew saw. Basically it was discovered that the crew
could deploy the reversers in flight if they moved the reverser handle
while the reversers where auto-stowing. 

The sync locks were also installed on the 757 with PW2037 engines since
they use the same reverser system.

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D.G. Davidson (TriStar500@aol.com)
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