Originally Posted by
Escape Path
May I re-ask my question?
Oh, and BTW, as MCT is a lower setting than T/O thrust, and taking into consideration that engines are usually certified to run at TOP for 5 or 10 mins, would it be "wise" leaving the good engine at the TOP setting for, say 4 or 9 minutes (depending on the limitation) when an engine fails? That way you get some little extra thrust much needed to get away from planet Earth
I would suggest that you leave the engine running at TOP for as long as required; ordinarily that will be a shorter period of time than the "approved time" for that rating to be used.
But if for whatever reason you are still "in trouble" when the clock ticks over that magic limit, there's no reason to pull back the power and possibly make a bad situation worse. If you need the thrust, you need the thrust. There's only one place it can come from.
And in making that judgement as to when it is appropriate to breach the engine operating limitations, it should be borne in mind that the engine is not designed to fail at 5 mins and 1 second; it's designed to run dependably for 5 minutes. It may in fact do a lot better than the 5 minutes, it just isn't approved to do so, and the likelihood of it keeping going will start decreasing the more you abuse it. But if it's a choice between abusing the engine and hitting terrain ... and by the same token, once you don't need the engine to complete the takeoff climb, it does make sense to baby it a bit and not push it any harder than you need. After all, the other engine just failed after a lot less than 5 minutes at rated power .. why take any chances with what may be your last engine...