Originally Posted by
cauchy
I'd be really surprised if an airline didn't have some sort of predictive model that estimates the risk of an ATC delay, especially when considering short to medium length delays (long and rare delays might be harder to do). Time of day, day of week, month of the year, and so on, probably give good clues as to the risk level. Dealing with these delays is an inherent part of running an airline and so there's nothing extraordinary about it.
Of course carriers do. But, that does not change the way one schedules.
Take a simple example of a nonstop flight between two points in the EU. On a clear day with no weather and no ATC issues and where the departure winds are towards the arrival point and the arrival winds are from the departure point, the flying time is 60 minutes. On the other hand, 10% of the time, there is weather adding 30 minutes, ATC adding 15 mintues, and the winds in either or both direction requiring a departure and/or arrival from the "wrong" direction, adding 15-30 minutes.
Putting aside ground time, the time from wheels up to wheels down is somewhere from 60 - 135 minutes, The average time for the flight is thus roughly 90 minutes. If one is the carrier, that is still useless. Should one schedule for 90 minutes, in which case the aircraft arrives 30 minutes early half the time and 30 minutes late half the time?
The trick is knowing when delays will occur, not knowing that they may occur.
As to the knowing when delays occur, air carriers do exactly that. Thus, during winter months, when the Jet Stream is more prevalent over typucal TATL routes, TATL air times are shortened or lengthened depending on direction of travel. On a given day, however, one can't predict any appreciable time in advance what will happen.
This is largely why it makes sense to leave professional commercial aircraft dispatch to licensed dispatchers and not judges of the CJEU.
