Re: 2 Vs 4 engines - CFM56 Engineering Dept Costs

Date:         17 Dec 99 01:57:42 
From:         Hugh Dickson <>
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Ernie Fidgeon wrote:
> wrote:
> > If you were an airline running a CFM56 fleet B737 / A320 etc. and you
> > wanted to buy a wide bodied Airbus would the A340 cominality (sp?) with
> > the CFM56 be much of an advantage when compared to the greater fuel
> > burn etc. of a 4 engined aircraft?
> If you do your own engine mtce and already are familiar with the CFM, it
> would be an advantage to do this.  In addition, IMHO the CFM family of
> engines is extremely operation friendly and very reliable compared to other
> types available.  Also, for its size, the 4 engined A340 is extremely
> efficient.  The fan area is smaller than othe 4 engined beasts and offers
> drag benefits therein.

Aloha,   When I worked for UAL I put in a transfer
request for the engine shop so I could work on CFMs.
Years passed and I asked why my transfer did not go
through.  NO REMOVALS.  They had six mechs.
working on the engines and did not need any more.
The only work being done on the engines were engineering
inspections to figure out how many hours could be had out
of the motors.

UAL used to "time change" the motors at 20,000 hrs.
Freight operators used to wait until failure at about
25,000 hrs

IIRC the core on the CFMs used to be the same butt
the 737 models had smaller fans to reduce the "vacuum
cleaner" effect.

As an aside: a UAL stretch eight flew a charter from Bombay,
India to Houston, TX.  They had enough fuel left to fly to SFO.
The company offered to fly the pax to SFO, cover expenses,
grant a plaque, and free ticket home.  NO takers.  LONG legs.

Regards,  Hugh