Spacecadet3
23rd May 2012, 23:50
When setting TO power, one has a choice of climb, climb 1, and climb 2. When using a reduced TO power setting, it automatically selects the climb setting, which of course you can override (for climb restrictions, etc). I have been told that from the viewpoint of the engine manufacturer, there is no advantage to use a reduced climb setting (after 15K ft, it doesn't matter anyway), as opposed to a reduced TO power setting which does increase engine life. Also from a fuel economics standpoint it is better to use max climb. Upon discussing this, we thought the only reason was to have a more comfortable transition from reduced TO power to climb power. I.e. for a significantly reduced TO setting, you would go to climb 2, which would not result in a thrust increase. Appreciate any thoughts on this.
kookaburra
24th May 2012, 17:34
The thrust reduction on the initial climb still helps to look after the engines.
Try looking at a high assumed temp T/O to full climb thrust and the egt increase at thrust 'reduction'(increase in this case) is quite a bit.
Not much point in minimising T/O egt then raising it 50+degrees at 1000'.
Airmanship may also decide for you a high climb thrust might be better.
You find that on significantly reduced thrust T/O, taking the climb thrust back up one notch (eg defaults to cl2, reselect to cl1) will often result in very little thrust change nicely.
Spacecadet3
24th May 2012, 18:27
kookabura,
Thanks for reply. Agree with your comments. But I've been told that the CLB setting is not recorded as far as engine warranty/lifetime info. I totally agree that it doesn't make sense to watch EGT increase when transitioning to CLB thrust. Maybe the info I'm getting from our fleet boss is incorrect. Also concur with picking the climb power to make a smooth transition.
Spacecadet