Take-off Flex/De-rate and Climb Derate - How do you do yours?

[Genghis]

I am interested to understand what are the different airline policies on the use of de-rate/flex during takeoff and de-rate during climb, particularly the latter.

Is climb de-rate generally selected on the basis of weight or climb rate?

Any thoughts or contacts to help advise on this subject would be useful.

Cheers :confused:

[reimers]

Lufthansa A320: We use Flex. T/O Thrust whenever possible. At 1500' AAL, CLB Thrust is selected, which is a fixed setting and cannot be derated. Seldomly we select something less than CLB Thrust (e.g. on FRA-STR or FRA-CGN sectors to get the pitch down without increasing speed in order to achieve max. useful flighttime for inflight service).

[Slick]

Genghis we also use an assumed temp reduced thrust (Boeing) aka flex Airbus + others, as much as possible. We do have a list of conditions which if present don't alow us to use an assumed temp, they are reletivly standard, will dig them out and list if you want ?.

As you probably know a de-rate is a little different in that it is fixed and should be considered a limitation. For the 73 I fly 22K or 24K de-rates are available.

As far as climb goes we can select a reduced climb 1 or 2, no policy. If the assumed temp used was very high the FMC will on ocasion select a reduced cllimb for you.The thrust mode annunciators will indicate the climb power mode. CLB-1 reduced by 3%N1 or aprox 10% thrust CLB-2 6%N1 aprox 20% thrust, this in increased to max climb thrust at aprox 15000ft.

Hope this helps if you need more ask.

Best rgds

Just read my post again, apart from the crap spelling one thing I forgot to add was that, although your maint costs are reduced using reduced climb, fuel costs go up. I am afraid we haven't done the math on this.

[ 24 August 2001: Message edited by: Slick ]

[Intruder]

In our 747-400s (GE engines) we use lowest allowable standard derated thrust (TO2, TO1 or TO) for takeoff, per the airport charts and gross TO weight. There is no policy for Climb thrust, but defaults match with TO thrust selected (CLB2, CLB1, CLB, respectively). Personally, I dislike CLB2, because of the significant reduction (especially out of SFO or other airport with significant terrain), so I use CLB1 minimum.

[Chris Lock]

We fly a GII and always use flex power based
on weight and balanced field length.