Originally Posted by
BraceBrace
Brake cooling schedule is a calculation for turnarounds, to give an indication of the minimum turnaround time - or leave the gear down for takeoff (performance penalty). On days with multiple sectors and short turnarounds, the overall temperature can still slowly rise as there isn't really time to let the brakes cool down. As the day progresses, every time you do a turnaround, the risk of running into a "minimum turnaround time" (or takeoff performance penalty due to gear down requirement) is bigger and bigger. Think hot 4/5 sector day with very short flights, extended taxi time, high payloads,....
In order to provide extra cooling to the brakes, Boeing proposes to lower the gear earlier on the sectors. The advantage is that your starting point in the brake cooling schedule calculation will be lower, hence less chance to end up with a turnaround time requirement (or gear down required after takeoff) after sector 3/4/....
Thanks for the response! However I still have 2 questions:
1) I understood that extending the landing gear early in approach contribute to brake cooling, but from what I understood from your reply is that we can’t determine the required time the gear needs to be extended during the approach from the schedules. Hence the schedule is not usable in this case. Correct?
2) During an RTO when recognize the rejected speed so we can obtain the brake cooling time from the schedule, I have read somewhere that if we couldn’t identify the RTO speed we can use V1. My question is how to determine the braking speed _after landing_ so we can see the minimum turnaround time (to cool the brake). Do we use Vref?