LHR Departures/Take Offs
 

Having time to kill waiting to meet someone at LHR yesterday I hung round in the spotters car park on the North side for half an hour around 2 15. The north runway tower controller was launching them at a cracking pace , very impressive , but it left me wondering who sorts out the order of queuing and the different queues as they approach the 27R holding point.

Obviously the departure controller is part of this but do the aircraft arrive at random or is it all very carefully planned by Ground to give her (in yesterdays case) a steady stream to 'line up and hold'. There were a few longish gaps after some departures soI assume she was busy with something, in one case a very courteous AA pilot who waited way longer than average for the 'contact departure message' nice prompted her with American xxx passing fifteen hundred to get her to transfer him to departures

All in all it showed both what a slick operation LHR ATC is but also the limitations on the airport, it would have been very very hard I am sure to better the number of deparrtues in the 30mins I watched given the mix of traffic she had to deal with

I can't answer fully, having been out of the loop for so long but I expect Gonzo will be along soon.. With separate AIR DEP and AIR ARR controllers life is more relaxed than with one person doing the lot! GMC will try to help, but GMC alone is a monumental task. As the aircraft approach the holding points, there is usually enough room to juggle the departure sequence. It's great fun..

Exciting though a free-for-all race would be, ATC know before an aircraft pushes back what its position in the takeoff sequence should be and direct its taxy route accordingly.

Having said that, I have it on good authority that Heathrow went to see McLaren at Woking a couple of years ago to have a look at the technology the F1 teams all use to schedule their pitstops efficiently so that cars can be slotted back into the sequence in the optimum position.

Sadly the rumours that the LHR taxiways are to be widened, with DRS zones, to make overtaking easier probably aren't true. :O

GMC can be fun anyhwere. it was introduced atbGlasgow in '72 whislt I was doing my ATCO Cadet training there and I took great pride in being able to sequence the taxyers so that the air controller could use the shortest possible departure intervals.
I was the first person to take and pass a 'validation' on GMC at Glasgow (those with a tower validation already got it rubber stamped)

PB,

As to who sorts the order out, it will mainly be the Air Departures controller themselves.

If it's particularly busy with south bounds, then Ground might position a north bounds at a different runway holding area entry point to make Air's job a bit easier, or do the same if there's a departure with a tight CTOT.

Generally there is enough of a spread of departure routes so that Air can make a good fist of it.

Contrary to Dave Reid's post, we know the flight's Target Take Off Time that the ACDM system is giving when the flight pushes back, but from that point onwards ATC don't see or use that time, and just try to optimise the order tactically. This will change in the future. There are many factors that the ACDM system does not take into account when posting the TTOT.

McLaren were involved, but that work was not followed through on.

However, a new venture of pre-tactical capacity planning does involve McLaren Applied Technologies, among other partners.