Originally Posted by
KC10 FATboy
USMCFLYR, I understand that you come from a community that enjoys afterburner takeoffs. Out of simplicity, you are given full mil or afterburner takeoff options.
Even in the military, we use reduced thrust takeoffs. An engine is statistically more likely to experience a failure at maximum power than at a reduced power setting. I don't have any source for that other that what was taught to me by Boeing during my FTUs.
During a reduced power takeoff, the aircraft must meet all of the same requirements as a normal power takeoff. If you lose an engine at Vcef/V1, you are still required to meet all performance requirements with the remaining engine(s) at the reduced thrust. In fact, in every aircraft I've flown with reduced thrust takeoffs, it was taught that you should not apply additional thrust (as it's always available to you) unless for some reason you need it.
I would MUCH rather fly an aircraft that has excess thrust available on takeoff, than an aircraft that needs maximum thrust available in order to get airborne.
Yes I do....and even though there are times when I would like to make a mil powered take-off (and maybe even a few times when I would make a mil powered take-off) we have to acknowledge that there is a significant safety factor that we are giving up. You've seen it on the video of cat shots even. The aircraft is NOT in A/B while in tension but halfway down the cat shot they engage the A/Bs - for that litttle extra safety margin; even though it is not required. I give it serious thought every time I do a section takeoff since I, as the lead, have pulled a couple of percent out of full A/B.
I understand that it seems to be common practice in the heavy transport community (military and civilian) to use reduced powered take-off per my earlier question and the responses received.
As far as statistical evidence that taking off at reduced thrust on the off chance of a engine failure at higher power vice the known safety margin that a full power provides (across all aircraft types), then I would have to say that IMO it is safer to use a full power takeoff. This would be an interesting safety study/discussion; but like you said - I have spent my entire career being taught that full power takeoffs are safer.
I am not familiar with the reduced pwer takeoff but I do understand what you mean when you say that aircraft must meet all of the performance requirements. I understand that they might JUST make those requirements (the mins), but that doesn't mean that it isn't safer to have a greater margin of making those minumums.
The earlier responses giving wear and tear as a reason for reduced power takeoffs seems right down the alley of the perserving the bottom line - the almighty dollar. In this instance - I believe it is a case of making a decision that a reduced powered takeoff saves gas, saves wear/tear, saves on noise and is GOOD ENOUGH to meet the safety requirements.
USMCFLYR