Re: ETOPS

From:         falke@pweh.com ( 0 Falke_Charlie phone dist )
Date:         12 Oct 96 02:35:58 
References:   1 2 3 4
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>It was an Eastern L-1011, flying from Miami to San Juan.  I don't have
>the date but I thought it was in the 1970s.  (Details appreciated if
>anyone can supply them.)

>The single point of failure in this incident was the mechanic -- one
>individual improperly serviced all three engines.  I believe one of
>the operational ETOPS requirements is that the same mechanics cannot
>work on both engines.

Karl,
   I don't have the date, but this is what happened:

1) chip detector plug lasts forever on shelf, but requires seal which
   has a cure date on it and doesn't last forever.

2) initially seals and chip plug are stored separately and seals
   are put on chip detectors only when they are installed.

3) This takes more time, so the station starts pre assembling the plug
   and seal for convenience.  They are installed both ways.

4) A mechanic who has only ever installed plugs with the rubber already
   in them gets three that have none, and installs them in all three engines
   of the subject airplane, about to head out over water.

5) Oil leaks.  Since it's common mode, and since their heading
   away from their maintenance base, they decide it's an indication problem,
   and press on.  They landed hard and short, with only one engine running,
   the first one that they had shut down, and later re-started.

The general ETOPS rule isn't to have different people work on each engine,
it's to try not to work on one of them at all before an ETOPS departure,
But none of these rules are actually rules, as far as I know.
Of course, it doesn't apply to the 1011 anyway because it has three engines,
which makes it safer, right? ;-)
   Our engines have a check valve that keeps the oil inside even if the plug's
missing, btw.  RR redesigned their's so you couldn't install it without the
rubber.

--
Charlie Falke                 Pratt & Whitney
System Test Team Leader       C/O Boeing Comm AP grp.