Re: ETOPS question on Aer Lingus A330

Date:         22 Nov 97 20:41:26 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
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>A carriers fleet or part of the fleet may be downgraded from 180 to 120
>or 90 based on operational performance of the fleet.  In some cases a
>carrier may be able to operate  one a/c type at 180 but only have 120
>min authority on another a/c type.  This is usually due to reliability
>problems on one type that are not present on another.  It may also
>reflect differing operating experience levels with the two types.

I suspect the most common reason may simply be need, or lack thereof.
Equipping and maintaining an aircraft to ETOPS requirements requires
more work and potentially more expense.  No point if you're not going
to use it on ETOPS routes.  That's why Delta, with more 757 / PW2000
experience than nearly any other airline, doesn't have any ETOPS 757s.

Likewise higher ratings -- you don't pay for 180 minute if you only
need 120.

>I do not know of any regulatory mechanism inplace that would allow an
>individual aircraft within a fleet to be partially down graded (180 to
>120 or 90).  The individual aircraft are either ETOPS or non-ETOPS,
>based on all ETOPS required equipment and systems being operational.

I thought the MEL included equipment that would be required for, say,
180 minutes, but could be inop for 120 minutes ETOPS.

>A carrier operating 767-300ERs with PW4000 engines may have worked up
>to 180 min authority, but if they added some 767-300ERs with CF6-80C2
>engines ...

Now why would any airline be crazy enough to do that?!  Oh, I forgot
you work for the engine-type-of-the-month club, er, Delta.  :-)

>... they may be restricted to 60, 90, or 120 until there is enough
>reliability data assembled to satisfy the carriers NAA that 180 is
>justified.

The reliability data is specific to the airframe/engine combo, not
the carrier.  Separately, the carrier has to be able to show that
it's maintenance and operations meet ETOPS requirements (regardless
of airframe/engine).  The 767-300 / CF6-80C2 has long been certified
to 180-minute ETOPS, so an airline already flying other types under
ETOPS rules shouldn't have any problem getting ETOPS certification
for the new combo.

--
Karl Swartz	|Home	kls@chicago.com
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Moderator of sci.aeronautics.airliners -- Unix/network work pays the bills