Re: designations from Boeing

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works
Date:         07 Jan 94 02:44:59 PST
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>Can anyone explain the Boeing designation system?

I thought this was going to be easy -- a simple matter of pointing you
to the archives of the group, which include a file named boeing-code
which explains the Boeing designation system.  (For those who don't
already know, archives of sci.aeronautics.airliners are available for
anonymous ftp on ftp.kei.org and rascal.ics.utexas.edu.)

>I refer specifically to the designation 757-236 which ordinarily I would
>associate with British Airways.  However, a number of British airlines have
>taken 757s with this designation.  I'm fairly sure that these were not
>orders that BA cancelled at the last minute, too.

Unfortunately, this is where my easy answer breaks down.  Yes, the 36
indicates British Airways, at least normally.  As I understand it,
most or all 757s built for British carriers use the 36 customer code
even if they aren't destined for British Airways because this made the
certification process either.  (They aren't cancelled BA orders.)  Why
this only seems to apply to the 757 is a good question, but like most
bureaucrat inspired lunacy there probably isn't a terribly palatable
answer.

>Malaysia Airlines (probably Boeing's biggest customer in 1993) has taken
>delivery of about eight 747-4H6s, some with GE engines and some with Pratt.
>Same airline, same type, same designation, different configuration.

The customer code, H6 in this case, is just that -- a *customer* code.
While that often will pretty succinctly identify configuration this is
not always the case.

I've found switching of engine vendors rather interesting, as it's a
very costly thing to do and in many cases it's not clear why.  Here
are a handful of examples:

    Malaysia 747-4H6 (GE CF6-80, then PW PW4056)
	I seem to recall someone mentioning that this was mostly a
	political decision.  To make matters worse, their lone 747-3H6
	came with JT9D engines, and they have a pair of ex-BA 747-236s
	with Rolls-Royce RB.211 engines!  With four completely different
	engine types *just* on their 747 fleet their maintenance costs
	must be incredible.

    QANTAS 747-238B (PW JT9D, then RR RB.211-524)
	When QANTAS first bought 747s the JT9D was probably still the
	only choice.  They may have switched due to the improved fuel
	burn promised for the RB.211 -- important for QANTAS very long
	routes -- or due to their British political connections.  They
	now only have a couple of P&W-engined 747s remaining, and all
	the newer models have come with the RB.211.

    UPS 757-24A PF (PW PW2040, switch to RR RB.211-535 in 1994)
	The RB.211 has about two-thirds of the 757 market and claims
	to have better fuel burn than the PW2000; perhaps this swayed
	UPS.  They'll end up with a substantial fleet with each type
	of engine so neither is really an orphan, which usually is a
	kiss of death.

    Delta 767-332 (GE CF6-80 on early domestic, PW PW4060 on others)
	This has always seemd truly bizarre to me.  Delta had GE
	CF6-80 engines on their 767-200s and continued with the same
	on their domestic 767-300s.  Then, while the -300s were still
	being delivered with GE engines, they started getting more
	767-300s in ETOPS (ER) form -- with PW PW4060 engines!  Why
	they'd do this on an ETOPS plane is beyond me, since they had
	no prior experience with the PW4000 series and I recall that
	the CF6-80, being a more mature engine, has the best in-flight
	shutdown rates of any of the ETOPS-qualified engines.  Then,
	to even further confuse matters, they switched to the PW4000
	for their most recent domestic 767-300s.

I'm sure there are other cases, and of course there are many, many
cases of such mixed fleets when one considers leases and purchases of
used aircraft.  Most airlines do seem to have rational engine choice
policies that attempt to minimize the number of engine types, though.
(Most consistent on a diverse fleet must surely be Cathay Pacific,
which until the A340s arrive will be exclusively Rolls-Royce.)

>Incidentally, does 8A as in 757-28A stand for Air 2000 or ILFC?  This is
>another one which has me confused.

The 8A code indicates Air 2000; Q8 would be ILFC.

--
Karl Swartz	|INet	kls@ditka.chicago.com		
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