Originally Posted by
Gonzo
Lists of permitted pre-0600 arrivals get exchanged between Heathrow, the tower and Swanwick to ensure only those who are permitted to land before 0600 do so, according to the night quota system.
Yes, certainly the overall number of pre-0600 arrivals is constrained by the Night Quota, although that of course applies on a per-season rather than a per-day basis.
Originally Posted by
Gonzo
Usually if a post-0600 arrival is permitted to land before 0600, it’s because it’s been swapped with a pre-0600 arrival that is running late that day.
That makes sense - the average number of arrivals before 0600 is usually around 14 (in Summer), though not necessarily the same flights every day. Having said that, there were a couple of days last month with 20+ 0430-0600 arrivals, with eight of them on one of those days having STAs between 0615 and 0635, most of them flights from the US.