Nice thread -
Chris nice explanation

, I couldn't have put it more succinctly - Flex power is the norm and has been since I started in the industry.
The one anonmaly in all this were the original IAE V2500s (A1's) which had a max continous thrust of 22,200lbs
but could be over ridden and exceeded to 25000lbs of 5 mins on take off - this was refered to as a "Bump" takoff
and as such the cycles on engine would be reduced by a factor of two for every "bump" (effectivly shortening the
TBOh) IAE countered this by beefing up the V2500s hot section and upping the max cont thrust to 24,800lbs.
Oh yes and Laker wasnt the pioneer to use Reduced Take Off power - Boeing was teaching Britannia Airways crews
the technique for the first 737s in the UK in 1967 When Laker was still trying to get off the ground in Britannias.
So Im assuming that if Boeing was teaching Britannia then the technique had been around for awhile.
Edit - Chatting with BrianH (Horse) on Skype this evening he confirmed that Quantas was using Reduced Power
takeoffs when he was an engineer with them - and that sort of blows the Laker theory out of the water - sorry
Leif