Re: ETOPS Question

Date:         03 Oct 97 01:18:33 
From:         Pete Mellor <pm@csr.city.ac.uk>
References:   1 2 3 4 5
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ae562@FreeNet.Carleton.CA (Eric Thomas) asked on Mon Sep 29 07:14:05 1997:-

> Speaking of which, would a FBW Airbus (say an A320) have been able to
> manage a "Gimli Glider" situation?

With difficulty! With a complete loss of all computers in
the Electrical Flight Control System (EFCS), the A320 (or
A330, A340, etc.) has a limited "manual backup" control,
which consists of rudder control by pedals, and pitch control
by moving the trimmable horizontal stabiliser using the trim
wheels. (Both rudder pedals and trim wheels are connected to
the flight surface actuators via mechanical cables.)

If the EFCS were lost, but engine power were still present,
differential throttle control could be used to assist. If
both engines were out, but there was still fuel on board, the
APU could be fired up.

Given loss of both engines and the APU (e.g., when the aircraft
is completely out of fuel), presumably the pilots would
deploy the RAT. This should generate enough power to keep the
EFCS going. The main question then is whether there would be
sufficient power to operate at least one of the three hydraulic
circuits.

I don't have time right now to research this last question.

Peter Mellor, Centre for Software Reliability, City University, Northampton
Square, London EC1V 0HB, UK. Tel: +44 (171) 477-8422, Fax: +44 (171) 477-8585
E-mail: p.mellor@csr.city.ac.uk
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