arrivals spacing

[pax2908]

Hello

A couple of weeks ago we were holding at CDG, for a long time (busy afternoon), I assuming waiting for permission to align on the rwy and take off. Many arrivals in sequence during this time. At some point a landing 747 was right over the threshold, while the previous jet (regional ?) could be seen turning left and vacating the runway. I think I saw the 747 land immediately after. How common is this (I mean, it seems a bit close)? Is it possible that I did not see what I think I did? Just curious...

Thank you

[HEATHROW DIRECTOR]

In reasonable weather conditions and during daylight there would be nothing unusual in what you saw. Under certain condtiions an aircraft may be "cleared to land" with the one ahead still on the runway - the controller anticipating that #1 would either be clear of the runway, or a certain distance down the runway such that it was perfectly safe for the next one to touchdown.

[as737700]

Some times it is common for 2 or 3 planes to take off really close to each other while a plane is final.

Ex.

A few years ago there was a Learjet on approach at Orange County (SNA), and the tower cleared an Alaska 737 for immidiate take off. While the Alaska was lining up, another Alaska told the tower that they were ready. The Learjet was now at 4 miles, and the tower told the second Alaska that if they knew they could take off quickly they could go. The 2nd Alaska said they could and just as the 1st Alaska took off, the 2nd Alaska released the brakes and was off 18 seconds before the Learjet landed. I knew it was 18 second because I timed it::p



So, in short, it's common

[HEATHROW DIRECTOR]

Yep... all in a normal shift for air traffic controllers; nothing to get excited about.

[HEATHROW DIRECTOR]

Hopefully one of the current ATCOs at Heathrow will provide chapter and verse but there are two types of clearance.

1. "Land after" Where ATC places the responsibility firmly on the pilot to decide whether it is safe.
2. "After the landing cleared to land" where ATC is applying certain criteria to determine that an a/c may land safely. (Of course, the pilot still goes around if he is not happy).

For 2, various conditions have to be met - a/c operating normally, runway dry, by day only and the one ahead must either have landed and be clear of the runway OR at least 2500m down the runway when the next one touches down. I THINK that's roughly the score, but stand to be corrected on the finer points.

[Richard Taylor]

Literally just had a "land after" at ABZ.

Wideroe Dash 8 landing after a bmi Reg EMB135 clearing at the end.

Plus ABZ has all its helicopters to contend with as well.

So happens quite often.