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Eurocontrol CTOT / airport slot assignments for light GA and how to get around them

My observations: From 2001 to about 2005, I was occasionally assigned slots. Note this was always for flights below FL150, but it mostly happened when flying in Eastern Europe, which I did a lot during that time.

From 2006 until just recently, this seemed to have ceased almost completely. I can probably count the number of slot assignments for that period on one hand!

Now, has anyone noticed a recent increase of ATC slot assignments for sub-FL200 GA IFR flights? I'm just back from a week's flying in France and Spain (more on that on a different topic), and have been assigned slots on two flights. One was Lübeck - Troyes and the other one La Baule - Le Touquet, so no busy airports at all. Also, the Paris TMA was not involved in any of the two flights.

Mere conincidence? Is it just France?

BTW, on both occasions the slots didn't create much inconvenience to me as they were timed just a few minutes after my EOBT, so everything worked out nicely - during preflight I merely had to keep a look at the watch a tad more cautiously than normally.

Also, I am thinking that should it happen to me in future to be issued a not so onvenient slot time, nowadays I would (thanks to Mr. Apple and Mr. Rocketroute) just quickly cancel the FPL and re-file whilst seated in my aircraft...

Egelsbach (EDFE), Germany

As a slot time is CTOT, a slot some minutes after your FP EOBT most likely means that your FP time is fine but the system wants you to adhere strictly to schedule.

I very rarely get slots now, although, as you say, it used to be quite common.

Mere conincidence?

I think so. 90 percent of slots I get now are weather related (if you get the CTOT message, it will say somewhere: "-REGCAUSE WE 7" or a different number). When there are for example actual or forecast thunderstorms along the route, the traffic flow is reduced so the aircraft can fly around the weather without getting too close to each other.

EDDS - Stuttgart

I used to get slots very regularly when departing from Shoreham EGKA to the east e.g. the usual KONAN KOK MAK etc route.

It was rumoured to be caused by a sector limit near DVR, whereby an ATCO might have a limit of say 30 planes for the sector, and even if all 30 were near FL300 then he would not be permitted to accept even one at FL150. However no ATCO I spoke to would ever confirm or deny this.

I never got slots for departures to the south (France/Spain) which is unsuprising because the French don't go for silly rules. I've never had slots in the south (Spain / Italy / Croatia / Greece) except a ~3hr delay at Greece in 2011 at LGKC when ATC went on strike.

I had slots at other places in N Europe which I mostly don't recall.

With EuroFPL (the paid membership) the slot messages arrive by SMS which is really handy. They also come by email but then you waste batteries / roaming costs by going online to check emails.

Virtually always the slot would shorten to the point where it practically vanished (maybe a 45 min delay reducing to a 10min delay which is irrelevant because you can start taxi 5 mins before the slot time) so in all cases (except the Greek sort of thing) one has to be ready to go at the original EOBT.

Cancelling and re-filing the flight plan is a very bad idea because it risks another slot (slots are allocated to flights in ascending order of the flight plan filing times) and also the airlines do every stunt imaginable to get around slots so Eurocontrol have written their software to frustrate that.

I haven't had a slot this year yet. I file FL140 usually.

Administrator
Shoreham EGKA, United Kingdom

I get a few on the London-Brussels-Cologne-Frankfurt axis. I don't recall a significant delay, and many are on-time slots.

Virtually always the slot would shorten to the point where it practically vanished (maybe a 45 min delay reducing to a 10min delay which is irrelevant because you can start taxi 5 mins before the slot time) so in all cases (except the Greek sort of thing) one has to be ready to go at the original EOBT.

If you send a SWM, the slot will be frozen and not brought forward.

What does SWM stand for?

Am I right in thinking that messages like SWM, RDY, etc. cannot be sent through Rocketroute? So how do I do it if I am still at home and want to freeze my slot?

Egelsbach (EDFE), Germany

It's a message which requests the slot to be frozen.

So if you get a 45 min delay and the client wants to use it to go into the restaurant or wants a pee...

Yes it is a problem how to send those messages when sitting in the plane. I think all the online services allow it if you can get onto their website. EuroFPL may allow it via SMS although I have not seen that in their list of message types.

Personally I would never bother with that because if you are ready at the original EOBT, why not sit it out and wait for the slot to gradually shrink?

Airlines do it by phoning their ops department (perhaps via ACARS).

Administrator
Shoreham EGKA, United Kingdom

It's a message which requests the slot to be frozen.

bookworm already explained that. I asked what the letters stood for. Well, in the meantime I have looked it up in the IFPS manual and it's "SIP wanted message" (where SIP stands for "slot improvement proposal").

Yes it is a problem how to send those messages when sitting in the plane

Why? When sitting in the airplane, you could just ask the Tower (or Ground) to do send it for you. I was more thinking of the case when you are still at home or on your way to to the airport (and thus can't radio with the tower).

Personally I would never bother with that because if you are ready at the original EOBT, why not sit it out and wait for the slot to gradually

Well, but you never know if it will actually shrink. Thus I would prefer to just take it easy in the morning with my breakfast and adjust my timing acccording to the slot. Much better than sitting in an aircraft an waiting (especially with passengers). But if you don't freeze the slot, you cannot do this because you would have to expect the slot to shrink and thus be ready for startup at the EOBT.

Egelsbach (EDFE), Germany

When sitting in the airplane, you could just ask the Tower (or Ground) to do send it for you

Because if the slot pops up after you left home (the usual case) you won't even know about the slot until you start the engine, switch on the avionics master, and tune in the radio.

And then you are unlikely to sit there for a while, engine off, battery running down, waiting for ATC messages for you...

At some airports, they send a van round when a Eurocontrol slot pops up, because usually one is doing the external preflight or something like that so obviously not on the radio.

but you never know if it will actually shrink

Unless you have appropriate connectivity while in the cockpit (e.g. SMS). IME, they shrink > 95% of the time. Most Eurocontrol slots issued to GA have no basis in reality; they are just software artefacts. The actual airspace is empty. I would happily give you £20 for every plane you can visually identify EGKA-LKPR cruising in the lower airway airspace.

Obviously different people have different workflows but if I wanted to depart 45 mins late I would have filed the FP at the later time. Usually one wants to depart as early in the morning as possible, airport opening time permitting, to benefit from smoothest wx, to arrive in time for lunch and a long relaxing afternoon, and sometimes even to reach the destination before it closes (EGKA-LDSB e.g.).

Administrator
Shoreham EGKA, United Kingdom

Because if the slot pops up after you left home (the usual case) you won't even know about the slot until you start the engine, switch on the avionics master, and tune in the radio.

Doesn't happen if you use Rocketroute which - I know - you don't.

Egelsbach (EDFE), Germany
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