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r304ndy
23rd Feb 2010, 23:09
To all Rolls-Royce powered widebody pilots out there!

Wanted to get your thoughts.... I heard somewhere that some operators of above aircraft/engine combination, e.g. SQ, EK, CX, KA, require their pilots to use climb derate as much as possible. If so, what effect if any does this have on climb rate compared with full climb thrust and likelihood to obtain your preferred altitude? I heard that operating aircraft above certain climb derate settings would incur a penalty by the airline to Rolls-Royce?

Can any pilots from any of these airlines confirm my curiosity please?

Thanks a lot!

extreme P
24th Feb 2010, 04:39
Wanted to get your thoughts.... I heard somewhere that some operators of above aircraft/engine combination, e.g. SQ, EK, CX, KA, require their pilots to use climb derate as much as possible. If so, what effect if any does this have on climb rate compared with full climb thrust and likelihood to obtain your preferred altitude? I heard that operating aircraft above certain climb derate settings would incur a penalty by the airline to Rolls-Royce?

I can't speak for company specific requirements however engines are still more expensive than fuel so as large a derate as possible is always favourable (windshear and the obvious conditions exempted...).

Obviously with less thrust the rate of climb is less but I doubt that has any impact on preferred altitude.

Contracts with leased engines and RR will vary widely I'm sure but one factor to lower costs is to use the engine lightly.

kijangnim
24th Feb 2010, 05:19
Greetings
Climb Derate is mostly used to reduce Hot Part Maintenance cost,
Takeoff Derate is also used for that purpose PLUS if leased " pay as per the output."

Wizofoz
24th Feb 2010, 09:03
HOWEVER,

Climb de-rate only reduces EPR until 12 000ft for the most popular option, so its overall effect on time-to-climb is negligable.

Interestingly, we operate both Trent and GE-90 varients of the 777, and SOP is now to use full climb fo the GEs, as operational experience has shown no maintenance advantages for de-rate, whilst full climb offers fuel savings.

Interesting document on the subject here:-

http://www.smartcockpit.com/data/pdfs/flightops/aerodynamics/Derated_Climb_Performance.pdf