Slot times
 

Can someone explain simply how the slot time in LHR works? Are these times booked months in advance by the regular airlines. How is it adjusted so quickly when "fully ready" is called for an earlier departure. How about delays? Appreciated in advance for the answer. :confused:

CTOT is managed at CentralFlowManagementUnit (CFMU) in Brussels. If you file a FPL which takes you in to regulated airspace it's mandatory to file 3hrs prior to EOBT if you want to get a reasonable slot time. I guess the slots are calculated 3hrs in advance.
For more acurate info: EUROCONTROL - Central Flow Management Unit (CFMU)

The slots are issued at the earliest, 2 hours before EOBT.

http://brahimtahiri.googlepages.com/..._atfcm_11a.pdf

Best Regards.

Are you talking about the airport slot.

or

Are you talking about the ATC CTOT which is also often referred to as a slot?

If you are referring to the airport slot: These people manage the airport slots in Heathrow and many other places.

Hi,

This is the ATC forum, so I was referring to the ATC SLOT (CTOT).

ATC slots are allocated a minimium of two hours prior to departure time

Fatfish.

I'm afraid SLOT times by their nature are not simple beasts! Each sector of airspace has a "monitoring value" for a set period (normally 15mins) stating how many aircraft should be permitted to fly through that sector.

Now sectors are split vertically as well as laterally. Thus if you file a flight plan and receive an outrageous SLOT time, refiling at a lower or indeed a higher flight level can change this as you may pass under or over a sector which is congested.

An example of this happens regularly on the EAST sector in London. The FlyBe service from Brussels to Southampton files at FL200 as it avoids the quite congested CLN (S14) sector at teatime and thus often avoids a SLOT. Brussels however will often climb the aircraft to FL240 as they are quiet, but before they get to the boundary descend said aircraft to the planned FL200 to avoid an overload.

So SLOTS are there to try and prevent overloads of sectors. It is not an exact science, thus the 15min window in a SLOT. Eg a SLOT of 12:00 is achieved if you depart between 11:55 and 12:10 (-5 to +10 mins)!