Originally Posted by
FCeng84
As SLF it has always seemed to me that similar sized aircraft are allowing almost exactly 2 minutes between departure brake releases. Doesn't that simplify things? For some departures the visibility will be such that one cannot see the airplane ahead in the takeoff sequence at the time that it rotates. Time is time is time and takeoff speeds will be similar for similar sized planes. Allowing 2 minutes between brake releases translates very closely to the same amount of time separation between rotations and even more closely to that amount of time separation when initially airborne. Am I missing something here?
The assumption that two "similar sized aircraft" will accelerate at the same rate on the runway and rotate at the same point at the same elapsed time after brake release isn't necessarily a valid one.