Hi guys!Using the PIC with the Hetherington / POSKY merge is working beautifully. However, From t/o to the top of the climb (to about FL380) with CLB-2 takes absolutely ages (at least 30-40 mins) and it really struggles. I don't adjust the weight, and I'm just using VNAV to control it.I just wanted to ask, is this normal? If there are any real world pilots here, can they tell me if they ever climb on CLB-2? If they do, how long does it take?Hope someone can help! I just wanna get it as accurate as possible!Cheers,Tom

CLB2 is generally used only through lower levels of the atmosphere. I would expect it would take an extraordinarily long time to climb with such a strongly derated thrust. I'm surprised it only takes you 30 minutes actually :)You should transition to CLB1 around 14-16K, and full CLB power around 22-24K. This will all vary depending on atmospherics and loadout.J

I like to add to that. Derated takeoff is generally used when full maximun performance is not needed for the particular flight as when on a short hop or are lightly loaded. Also, There is the assumed tempt reduction method. In real world flight, at takeoff, stress on the engines is greatest, so using a derated takeoff saves on maintenance etc and will prolong engine life. If used correctly, there should not be any significant difference in climb performance.Best Wishes,Randy J. [email protected]" A little learning is a dangerous thing"

In the real aircraft, as I believe Ian Riddell once explained, CLB 2 eventually (i.e. at high altitude) equals full CLB thrust. In FS you must however select full CLB thrust to get it even at altitude.Martin767 fetishistIt's a lot like life and that's what's appealing

Actually this, like so many things, is a carrier option. The AA 767 which we modeled does not have this feature, therefore neither does PIC. I believe SOP for AA is to switch to CLM after 12,000.Regards,Wade

Thanks guys. That's very interesting. I'll move onto full CLB at about FL120.... (Europe flyer ;))Interesting topic, though. I normally de-rate my t/o to 60 degrees, if that makes any sense.Regards,Tom

It varies depending on engine type.Our CF6 and RB211's maintain the 10% (CLB1) or 20% (CLB2) derate to 10000ft, then reduce linearly to full CLB thrust at 30000ft.Our JT9D reduce from 10% or 20% at sea level to 4% at 12000ft, which is maintained throughout the climb.Our procedure is that a takeoff below 160000kg uses CLB 1, and takeoffs above 160000kg use CLB until flaps are retracted, then CLB 1 (this is a new procedure, used to use full CLB all the way, but engineering decided the benifits of CLB 1 out-weighed the increased climb times).

"but engineering decided the benifits of CLB 1 out-weighed the increased climb times)."Hopefully not the same guys who recommended Flaps 25 and idle reverse for most 747-400 landings ;-)

Dont worry Ian, that was a pilots idea...(did I say that?)

As everyone has stated it is carrier specific.Air Canada does not use derated climbs.

>As everyone has stated it is carrier specific. >>Air Canada does not use derated climbs. You sure about that? Sounds a little odd IMHO.

My company does not use derate, however we use assume temp takeoff for both 757/767... The highest assume temp for the 757 is 49 degree and 54 degrees for the 767.. Again this is also company specific sinne my company didn't buy the extra package...We always use CLB1 when we use assum temp, but I've never seen any pilot use CLB2.. I'll try it next week and report back...Hope this helps.

Pilot's I have recently spoken to at ACA confirm Ryan's statement - after takeoff, it's CLB all the way up, not CLB1 or 2.As has been said, different airlines, different preferences.Rob.

Hmm, ACA 767s must climb quickly then!

Our 757's have the CLB fixed reductions. We never use CLB-2 but use CLB-1 as standard. The main benefit is that we get a discount from Rolls Royce! Regarding fuel efficiency, it is actually more efficient to use full CLB thrust but by using CLB-1, stress on the engines is significantly reduced. At all weights up to 95 tonnes, it's no problem to leave CLB-1 all the way up to cruise level, however since we are spoiled with such a powerful machine, CLB-1 is discarded once vertical speed gets below 1500 fpm.Iz