I've never heard of this. Any a/c that I'm familiar with
certainly don't modulate takeoff power according to their weight.


Bob's explination is 100% correct we use reduced Takoff power to save wear and
tare on the engine these engines are running in excess of 10,000 hours before
removal.
I fly a 727 at fedex, We generally fly at weights above the passenger carriers.

The option of max thrust is always availabel but in my case in the 727 the
plane flies fine with engine out at reduced power. Max power is always avilable
then in extremis there is red line power as well as firewall power.
The weird thing is we use a Laptop that is programed with the modex as well as
all the airports and runways we are authorised to operate out of so it is
really easy to compute T/O performance as well as trim setting.The two things
we arn't provided is the takoff distance or a line speed check #.
I asked in training and they really don't seem to think those are things we
need to know. The reason more 727's arn't crashed is because the plane flies
better than the sim.
Sparky