100kts
E/O calls "Power set" if you have a minimum of 4 engines and 3 reheats (for a "goer" - your flippy thing set to "3"!) else "Engine Fail" and therefore an RTO. 4-engines and 4-reheats (4 greens) needed at 100kts for a "power set" call for a "stopper" - flippy thing at "4". It was simply how far off TOW was from PLTOW and a concept introduced following a commercially unacceptable number of RTOs which weren't necessary from a perf-A POV...
(A single reheat failure, although rare, could be accepted after 100kts at any weight)
(Just noticed Brit312 covered this earlier - sorry!)
Last edited by NW1; 25th Oct 2010 at 02:29.