Thank you for your posts and special thanks to certain gurus.
(f) with an aircraft engine, we want to be able to have our cake and eat it too - ie sometimes we want to operate to the maximum rating and, on other times, to a derated rating. However, we don't physically swap engines back and forth - that just wouldn't work in practice.
What we can do to achieve the same thing, in principle, is constrain the engine not to operate at power outputs higher than the declared reduced rating level. This can be done either by computer control or manual setting of lower power output using the engine gauges
To add few information to previous quote, here a quote from this link:
Assumed Temperature Thrust Reduction
When an engine is de-rated, the full (un-de-rated) thrust is no longer available because this would require changes to the EEC, HMU, fuel pump, engine ID plug and the loadable software; non of which can be done by the pilot in-flight.
a)For takeoff and approach, there is an assumption of one engine failure regarding the climb gradient. Why not such assumption on landing (3.2% with all engine operating)?
b)How a takeoff thrust time limit (5/10 minutes) can affect the aircraft (take off climb gradient, takeoff path,…)? Does this occur in reality (a fact and not only a theory) only during takeoff or even during go-around (missed approach, engine failure)?
Feedback appreciated
Regards