Pilot says: Is this normal?

[Young Paul]

At LHR, at 1434 I called up with a slot at 1449 to start. But I was told that I could not make the slot, because of the queue of aircraft for 27R and runway alternation at 1500. So I had to have a new slot requested. Consequently, we were delayed by another 20+ minutes.

But surely the idea of slots is that it is what all the ATC agencies agree that they can make? I never asked for the 1449 slot, but I could make it (the standard taxy time is 16 minutes). But when I was ready to go, ATC said they couldn't make it.

Come on, guys - it wasn't me who wanted the slot!

[ferris]

Obviously this calls for taxiway slot times.:rolleyes:

[ATCO Two]

Send me details of callsign, stand number and routeing and I will investigate. What I would say is that the CTOT system is not really flexible enough to deal with short term tactical and local airfield delay situations. These cannot be effectively factored into the CFMU calculations. We were in LVPs for much of yesterday morning which caused a backlog to operations later on.

[Young Paul]

I can do ... but although it annoyed me a bit at the time, I only mentioned it because it seemed a bit unreasonable for us to lose a slot that we ought to have done enough to make.

In a very large number of times in and out of LHR (over 5000), I'd not come across it before. In fact, the competence of all controllers at LHR exceeds any I've come across elsewhere.

[HEATHROW DIRECTOR]

Paul... During my 23 years in Heathrow Tower I encountered many, many pilots who felt similarly hard-done by. Problem is that YOU and THEY didn't know the overall picture; the only people who do work in that tall building in the middle. Maybe you could have physically got out there but maybe everyone else at the hold was just about going to make their slot so if you jumped the queue a dozen other a/c might have missed theirs. You also have no idea how many other aircraft are starting with similar or earlier slots, or how many there are in queue.. Depending on the runway 1434 to 1449 would have been tight in the days I was there when traffic was less - on easterlies I would probably not have approved start-up unless you were on the J or K stands, for example.... and you say there was a runway change in progress! No way Jose!!

[161R]

From the EGKK perspective, if you’re given a CTOT, it will be not less than EOBT +20 (summer), or +15 (winter). Providing you call ready at EOBT ±5, you will normally arrive at the hold in sufficient time to make the slot. If you are inadvertently late starting, resulting in a “tight slot”, my sympathy extends to you, but also to the non-slotted chaps who arrive at the hold and are then held whilst a stream of “tight slots” depart before them. We don’t like having to have to negotiate a new slot, because we often get delays of HOURS, so if we result to this course of action, as HD has indicated, there’s always a very good reason!

[ATCO Two]

Good, relevant comments above. When there are airfield delays the CTOTs are taken into account, and it is usually the unrestricted aircraft who suffer the longest airfield delays, simply because of the difficulty of negotiating another CTOT and the possibility of long en route delays as a result. If there are a lot of aircraft in the system already, then unfortunately aircraft with CTOTs that in the pilot's opinion can be easily met, have also got to be subjected to the airfield delay. The OVERALL flow rate is still maximised. At times of runway alternation, start ups also have to be regulated to ease the workload on GMC - opposite direction routeings, choice of departure runway as 1500 approaches, involving close co-ordination with Air Departures, etc.

[No Mode Charlie]

Now correct me if I'm wrong but I always thought that the whole idea behind start-up control was to NOT have big queues.

If you give to many of us start and push, we will form a queue and burn loads of fuel between us. Wasn't the original idea to queue people for start and push and then clear them when it would work out for them to do so without sitting in another queue for take off?

[Richard Everest]

How much time is allowed for taxy in the slot calculation?

[ATCO Two]

Hi No Mode C,

Exactly! This is the precise function of Ground Movement Planning.

Hi RE,

Taxy times are specified for each runway at EGLL. For 27R it is 16 minutes for example. We expect aircraft to arrive at the holding point at the beginning of their CTOTs to allow the most efficient departure order to be achieved.

[flowman]

The amount of taxi time allowed for in the slot calculation is supplied by the aerodrome concerned and is often dependent on the rwy in use.
This figure can be changed dynamically in the slot machine if an aerodrome makes us aware of a specific problem (e.g. taxiway closure, w.i.p., fog, runway change etc.)to anything between 0 and 40 minutes .
If a longer taxi time is entered then allocated slots will be revised to a later time.
The trick is knowing when to change the taxi time! I suppose that's down to the experience of the Tower supervisor.

flowman

[Gonzo]

No Mode Charlie,

ATCO Two is right, but if I'm doing departures then I'd far rather have eight or nine at the hold waiting for for departure than just one or two with ten minutes airfield delay, it's more likely then that I'll be able to launch them in a decent left/right/left/straight ahead order, thus maximising runway use.

Gonzo.

[161R]

No Mode Charlie

In the ideal world, minimal queuing is what we always aim for. However inbound aircraft waiting for your stand, or pressure for an "on schedule" departure - where this means off-blocks rather than airborne - results in more aircraft taxying than is necessary to acheive the ultimate runway utilisation. When the limited remote parking is already occupied, I'm afraid you'll end up queueing somewhere, unless you want to delay the arrival of the aircraft (company?!) waiting for your stand, or you can withstand the pressure from company for an "on-schedule departure"!

161R

[Yellow Snow]

And to think it wasn't 'C' watch that were on!!!!!!!:)

At LHR there are ATCO's who will put delays on for virtually nothing and there are those that are happy to fill up the airfield; but providing GMC is protected then it's my opinion that it's best to get them started and off the stand, thus freeing up the ground crew and the stand for inbounds. And as Gonzo says ($hit I'm agreeing with him) it's best to have a decent mix at the holding point to get best runway utilisation, as I'm sure HD wil agree it's best to have the stacks half full so you can get a good approach order?

Also you pilots love getting off the stand 'cause you start earning flight pay?;)

Where's the Captain Creamgasser. Thought you'd be in this thread?:D

[Captain Spunkfarter]

Yellow Snow

We did an impression of C Watch in the Tower the other day. It was Remembrance Sunday and we had a two-minute silence. :D

Funny though, 'cos even though no-one spoke, we still exceeded C Watch's movement rate!

[Young Paul]

For what it's worth (which isn't much) I get flightpay all the time I'm at work. Productivity counts when I'm off blocks - but I so rarely get close to the overtime threshold (74% of max legal flying over 28 days) that I don't even bother considering it.

I just want to get home on time. (Or if that's not an option, to the hotel).

[ATCO Two]

Hi Paul,

I did an unofficial investigation into your case and the situation was exactly as I had thought. There was a backlog due to LVPs in the morning; there were a lot of aircraft that had been delayed and although you could have physically made it to the holding point to make your CTOT, you would have penalised other aircraft in the queue. Heathrow ATC have to take a wider view of the situation and try to be fair to all operators in these circumstances, to provide the most expeditious and efficient departure rate. The situation was compounded by the runway alternation at 1500. I am sorry that you lost out on this occasion, but I am sure you will agree that the delay you suffered was not excessive. In the future if you suspect that there may be airfield delays, contact GMP as soon as you are ready and book your place in the departure queue. If you wish to discuss this further then please contact me again.

[Young Paul]

Thanks. As I have said already, I really have a great deal of confidence in you doing your job - it's just I'd not come across something quite like that before.

[FlapsOne]

An interesting topic.

This exact subject came up several months ago. The debate was similiar and the bottom line highlighted the short-comings of the whole slot system.

We are left with a situation in Europe where many airfields adopt a differing approach to slot management - particularly with regard to the interpretation of the -5/+10 aspect. Local regualtions are plentiful, and sometimes poles apart, and it makes it impossible for flight crews to keep abreast of the differing procedures for the many airfields they visit on a weekly basis.

It is very sad in this day and age that a flight on a route where there are no flow restrictions can suffer delays, sometimes extreme, because flights on other routes have to receive priority because of restrictions.

In a busy Summer 'No Slot Required' can be the kiss of death!

The European slot system is long overdue for a complete and thorough overhaul because I am not convinced it is achieving what it set out to achieve.

I am not spoiling for a fight here - I know you are only working with what you are given.

PS. If anyone has the 'Big Picture' could they fax it in A4 sized pages so I can put it together on a day off?