Morning ATC slots into Heathrow

[Gonzo]

The flow system at the moment just sees 'a flight', not what vortex category. If the system could be 'tuned' to that level, obviously that would be an improvement. Likewise, at LHR a particular aeroplane's taxi time can vary greatly depending on which terminal (and from which stand within the terminal) it's operating from. 09R for departure, a T1 departure might need a taxi time of 30 minutes if there's a decent queue, but a T3 depature might only need 10 minutes. The system can't differentiate to that level, so we have a compromise of 20 minutes, which means quite a few T3 flights get delayed on stand waiting for the slot, but many T1 flights are delayed because they miss their slot times.

As to your 'dream scenario', I don't think it will ever get to that. The work being done is varied. I've been involved in some of the initial discussions. Some of it is actually just changing each ATCO's way of thinking. Most ATCOs will work really hard to provide the best possible service to the flights under their control. However, when in comes to 'network management', providing that level of service to one flight is actually to the detriment of the network as a whole.

For instance, an ATCO down at LACC Swanwick manages to get a direct routeing for a flight out of northern europe going to Manchester, which saves tens of track miles, and thus time. However, that flight was given a CTOT calculated upon the flight plan route. A/c now turns up early and creates workload at Manchester.

An example that was described to me at a network management conference I attended a while ago (apologies to any CLN or North Sea ATCOs, my memory might have lost a few bits, but you get the idea!): LACC North Sea and CLN had been busting a gut to get direct routeings for EBBR and EHAM transatlantic outbounds that were joining the northbound flow up past Daventry. However, because North Sea was doing (to them) such a good job, the aircraft kept joining the northbound airways just at the point and level where inbounds to EGCC and EGGP etc were descending through, thus creating lots of hassle and very high R/T loading on Lakes. If the aircraft had been kept on the flight plan, they would have joined the nortbound
flow at a different point in a much easier fashion.

This was the reasoning behind the recent '250kts on departure' trial in the London TMA. The more 'standard' each flight is, the more predictable and stable the environment is, and thus flow management becomes more effective.

Ok, it feels as if I'm rambling now, and I'm sure I've probably confused you! I've confused myself!