Re: 2, 3, 4 engines-- what's actually safer?

From:         rdd@cactus.org (Robert Dorsett)
Organization: Capital Area Central Texas UNIX Society, Austin, Tx
Date:         23 Mar 93 11:02:29 PST
References:   1 2 3 4 5
Next article
View raw article
  or MIME structure

In article <airliners.1993.256@ohare.Chicago.COM> gabrielh@tplrd.tpl.oz.au
wrote:
>|> Yes, there is a quite recent example.  Kegworth, England.  There was a
>|> fire in one engine, and the crew misinterpreted the indications and shut
>|> off fuel to the *other* engine.  QED.  (Details from memory.)
>
>I believe in this case the fire warning indicators for the two engines 
>were incorrectly wired (they were reversed). 
>
>There was NO error on the part of the crew. 

The switches and indicators were correctly wired.  It was crew error.

There was a *separate*, *independent* set of reports that the ever-diligent 
media dug up in order to provide "possibilities," following the crash.  Media
behavior in this case was similar to that following the recent El Al crash: 
the most spectacular AD on the top of the stack, dealing with a likely 
subsystem, got the most publicity, even if there was little reason from 
published evidence to indicate a relationship.  In this case, the press ran 
away with its conjecture, especially in England.  And, as always, the final 
results are given less "sensational" coverage than the original coverage.

The AAIB (Aircraft Accident Investigation Board) found that the cause was
crew error, and listed a long set of human factors issues that needed to be
addressed.  Paramount was the use and design of the Smiths Industries 
LCD-based engine instrumentation, which provides digital instantaneous
data and a low-resolution LCD "needle" for trend vectors.  This type of
display, while undoubtedly much cheaper to produce than conventional electro-
mechanical dials or CRT displays, has significant problems (to my mind obvious
problems--I couldn't believe the first pictures of the prototypes that were 
published in AvLeak).


>BA examined several other Boeing aircraft from the same order and found 
>they had the same problem. I can't remember the plane type
>but I recal the episode prompted quite a stir in the UK and at Boeing.

Boeing had a quality control problem in the mid-late 80's, due to an explosion 
of orders and a shortage of qualified manpower.  These received quite a bit 
of press, both before and following the Kegworth accident.  They started 
following the JAL disaster.  By 1990, the reports had stopped.  

Boeing's immediate response was to hire a lot of experienced workers from 
Lockheed; it also tightened up production standards to reduce the possibility 
of "wrong connector" type incidents.  A few latent reports about a drop in 
overall workmanship (BA, I believe, refused to accept a plane that had a bad 
finish) persisted.  One of the av-rags noted that more airlines were keeping 
their own inspectors on-site to monitor the progress of their airplanes.
This used to be a standard practice, years ago, but died out.

Boeing disputed the significance of the problems reported, claiming they
were well-documented isolated incidents.   And, in all fairness, the organ-
izations doing the complaining had been themselves under the spotlight,
and needed to be perceived as being "on the ball."

A minor nit: note that the airplane in question was a British Midland 
Airways 737-400, not a BA 737.




---
Robert Dorsett
rdd@cactus.org
...cs.utexas.edu!cactus.org!rdd