Re: ETOPS question on Aer Lingus A330

Date:         29 Nov 97 03:24:28 
From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
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>> The reliability data is specific to the airframe/engine combo, not
>> the carrier.
>Not entirely correct, as I understand the system.  Each carrier must
>maintain a diversion rate and/or IFSD rate ( I forget the exact numbers)
>below an established limit for each ETOPS airframe/engine combination in
>the fleet.  For example just because carrier A's IFSD rate exceeds the
>limit for the 767/PW4000 aircraft it operates it does not mean all
>767/PW4000 aircraft in the world are now downgraded.  Also a carrier
>operating, for example, A310/JT9D-7R4 may lose its ETOPS authority on
>that aircraft due to an unacceptable IFSD/Diversion rate while
>maintaining ETOPS authority on its 767/PW4000 fleet.

Right.  I should remember that, since I was once on a United 747-400
that lost an engine just after takeoff, and afterwards the pilots were
griping about all the paperwork required by ETOPS rules.  When I asked
about this, they pointed out that United's 767-300s use essentially
the same engines (PW4000s in their case) and thus an IFSD report had
to be filed even though the 747-400 is not an ETOPS aircraft.

Nevertheless, the basic airframe/engine combo has to be certified for
ETOPS.  The, the airline and its operations and maintenance have to be
certified.  It's not clear to me that this depends on experience with
the airframe and/or engine for which ETOPS clearance is being requested,
though once in service the airline's other experience with the engine
is clearly relevant.

All of this ignores the special rules used for ETOPS-out-of-the-box
used for the 777.  United's experience with the PW4000 on the 747 and
767 probably helped with the airline part of the certification, but
the PW4000 on their 777s is a substantially different engine.

I tried looking for ETOPS info in the FARs, but couldn't find anything.
Can anyone cite the exact FARs that cover ETOPS?  That's only for US
carriers, but the rules in other countries are similar, and the FARs
have the advantage of being on-line and this easy to refer to.

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