Originally Posted by
Lord Bracken
Concorde engines didn't all spool up at the same speed (3 + 1 iirc) so this was normal.
Indeed - this was discussed in detail on the old thread here:
Originally Posted by
Bellerophon
You call 3-2-1 Now, start your stopwatch, pre-set to countdown from 58 seconds, and slam the throttles fully forward till they hit the stops. Four RR Olympus engines start to spool up to full power and four reheats kick in, together producing 156,000 lbs of thrust, but at a total fuel flow of 27,000 US gallons per hour. A touch of left rudder initially to keep straight, as the #4 engine limiter is limiting the engine to 88% until 60 kts when it will release it to full power.
And some further detail on startup at pushback here:
Originally Posted by
M2dude
The trick was to get as many hydraulic systems online ASAP during engine start/pushback, and that's where the sequence was defined. Now my tired/worn out/time-expired brain recollects that number TWO engine was started first, this gave us GREEN and YELLOW systems, followed by number THREE engine, which now gave us BLUE system. Once these engines were successfully started the 2 air start trucks (oh for that darned APU) could be disconnected and preliminary system checks, including full and free flying controls, could be carried out. After push-back the outboard engines were started by using adjacent engine cross-bleed (as BRIT312 quite correctly stated years ago, there was no 'cross the ship' cross-bleed duct), the remaining system checks would be carried out.
Something I recall from the time I was reading these discussions was that during critical phases the FE would have been watching the engine instrumentation like a hawk, and given that the takeoff run was proceeding relatively normally prior to strip contact it would be far more likely that abnormalities in that instrumentation would have been the trigger for engine shutdown rather than a split-second increase in vibration. All evidence suggests that the crew thought they were dealing with an engine fire and had little time (or inclination) to determine its cause in the short time between strip contact and impact.