Hi,
Just a word from an engine guy: I'm fully aware of the 5 min. TO limit, and I also know that an extension to 10 min. (authorized in some jurisdictions) is merely a paperwork exercise (maybe with some shekels crossing the palm) - no spanners ever touch the engine.
And in my career doing performance tests on engines, we started with a 5 min. warmup at MCT, then pushed up to rated TO for 5 min., backed down a few rpm for another 5, then an alternate TO rating for another 5, etc. for a total of 30 to 45 minutes ABOVE MCT. I've done this DOZENS of times, never any hint of an incipient failure. (I shudder to think of the JetA I've burned...)
My message to pilots: Find out what your examiners expect you to know, but when one's churning and one's burning, FLY THE AIRPLANE and don't worry about that other donk!
Barit, are you talking about installed thrust or uninstalled thrust?
I think you are talking about engine on a stand.
During takeoff, pneumatic/electric/hydraulic power are extracted from engine. In addition there is engine air inlet fitted in the engine. These factors affect the engine.
Takeoff thrust may be used only for a maximum of five minutes, with one exception: the time limit is extended to ten minutes for airlines that have purchased a special Airplane Flight Manual appendix called the “ten-minute appendix”. The Certificate Limitations section of that appendix states specifically:
“The time limit on the use of takeoff thrust is increased to 10 minutes provided this use is limited to situations where an engine failure actually occurs and there is an obstacle in the takeoff flight path.
I think this quote is from Boeing document.