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philbrown

Derate Washout

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Is there a level at which any derate selected for departure washes out? I ask, because during a flight I conducted the other day, I was having difficulties climbing through the mid-twnety thousand feet. The rate of climb was about 700fpm. I checked in the FMC, and the thrust was still set to 60*C derate.All the other FMC-based aircraft I use have a level where the derate set for departure clears, and full climb power is used for the remainder of the flight. On the 777, I had to manually select CLB from the thrust page once I noticed the problem.Thanks for any info.

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From the BA 777 FCM"Derated Thrust for ClimbEngine maintenance benifits may be realised by operating the engines at less than full climb rated thrust.The level of takeoff thrust will dictate whether the FMC will defualt to CLB, CLB1 or CLB2. On passing 10,000ft derated climb thrust will automatically and linearly increased until full climb thrust is restored by 12,000ft.The above selections can be altered manually but unless there are imperative considerations there should be no need to do so. However, if the rate of climb should drop below approximately 500 fpm the full climb rating should be selected."My 777 re-rates the TO's fine, and changes into CLB, CLB1 or CLB2 as asked on passing AA with VNAV in, and the washout completed by 12,000ft.A 60'C de-rate in a 777 is a little OTT, on "Normal" days ie, not too hot or too cold say 10-25'C a normal de-rate is around 30-40'C, however de-rates are down to weight, runway and obstical clearence.Cheers

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