Originally Posted by
USMCFLYR
And the primary reason for using reduced take-off thrust is which of the given reasons (fuel, wear/tear, or noise) - or something else?
USMCFLYR
Heat is the big factor in engine life. Higher heat equals less life. For example, historically the Russians have burned their engines at much higher temps and got more thrust but shorter engine life.
The airlines figured out that if they could get an airplane airborne without using all the thrust, and still meet all FAA requirements then why use the extra thrust. You can use reduced thrust via 'assumed temperature' and/or a 'derate'. In some cases, both. And you wind up rolling down the runway with about 86% N1.
The big thing for me was to check acceleration. With a lighter airplane, your acceleration with reduced thrust should be about the same. So, on the 737 for example, as I remember I was looking for 100kts by 2000ft on takeoff roll.
The military didn't use reduced thrust when I was in but they did use min accel checks. Seemed to me the best option was to use both.