Re: A 777 with four engines.

Date:         18 Aug 98 01:04:43 
From: (Darren Rhodes)
Organization: Daz Technology
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On 06 Aug 98 11:26:36 , (C. Marin Faure) wrote:
>This is not true of turbofan engines, as long as temperature and N-speeds
>are not exceeded.  If you look at the graph representing the chances of
>failure vs. power output of piston engines and turbofan engines, the
>failure rate line climbs steeply with power output from a piston engine,
>but remains relatively flat with turbofan engines.  In other words, a
>turbofan doesn't care what power setting you use so long as its
>temperature and rotational limits are not exceeded.  Pushing the power up
>on the remaining engine of a twin-engine jetliner does not add to the risk
>of engine failure as it would if you were flying a twin-engine piston

I have heard of a 747-400 operator that has 9 out of 10 engine
shutdowns at high power, i.e. during takeoff.

Temperature exceedance is one thing, but reduced margin at high power
on high time turbine blades is an issue.

Mr. Darren P. Rhodes, BEng. (Hons)        | Aircraft Performance
Email:  | Analysis & Noise
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