For years, I have not been subject to any slots. Last weekend, I got a double dose of it (Achim knows about it) and I wonder if there is a general trend there.
First flight was from Northern Germany to Southern France. I filed the flightplan the night before , and shortly after, I started to receice several slot messages, ranging from about two hours delay to almost ten(!) hours delay. And yes, it was fluctuatimg back and forth – crazy! luckilx I was sleeping already and didn’t bother. The next morning, the delay was at about two hours and then changed to just over one hour.
As I didn’t like that, I tried a few old tricks, like canceling and refiling the same flight plan, changing the departure time by a few minutes etc. Achim warned me that this might take me “to the end of the cue” again, but that didn’t happen – immediately received the same slot time as before (apparently, the computer is not that stupid any more). Changing the routing is not that easy nowadays, since because of numerous airway restirctions, that usually means a huge detour.
By the way, the mentioned reason for the slot was “ATC industrial action” in France, but apparently, no strike or similar was notified. No idea what to think about that.
About one hour before the original EOBT, the delay went to just over half an hour, which, in the end, wasn’t too bad, as it gave me just enough time to do everything “con calma”.
For a change, the return flight way planned via Switzerland (Geneva, Zurich, and then north into Germany). Bad idea – I got slotted by the Zurich sector. It was a couple of hours initially, but again, in the morning, it went to something like half an hour. Damn – I really didn’t need that.
So, I am really not too happy. The problem is not only the delay in itself. It’s the hassle and tension, because you cannot adjust your morning pace to the slot, because it might just as well disappear at any time (which is what often happens).
Anyone had any similar experiences with France or Switzerland recently? Achim said that Switzerland is a big problem for low-level GA currently…
Anyway, lessons learned (not all new):
-slot delays end to “recduce” with time – so don’t panic
-they either disappear or often settle on 30 to 60 minutes
-so: file the earliest possible departure time you can imagine, then delay if required
-be wary of slots in France and Switzerland
There was French ATC action Saturday.
But then, slots don’t make much sense, do they? if everybody gets shifted back by 30 minutes, the traffic will not be less, will it?
In that case, it is just first come first served so they limit the number of aircraft in the sectors. Maybe you filed for a busy time. there weren’t any slots at FL390…. 
The old cancel and refile definitely doesn’t work any more. I tried it when the UK computers shut down two years ago. Ended up with a later slot.
I had exactly the same when i flew to Nancy/F this spring. First it was delayed by two hours, then I took it easy and all of a sudden it came back almost to the original time … Back then it was “industrial action” too, many controllers did not work that day.
I got a slot on Tuesday from Spanish ATC that delayed my departure from EDDS for 1.5 hours. I guess it was due some CBs right at the STARs of Barcelona El Prat.
I delayed earlier for 30 minutes and got added an additional hour.
boscomantico wrote:
So, I am really not too happy. The problem is not only the delay in itself. It’s the hassle and tension, because you cannot adjust your morning pace to the slot, because it might just as well disappear at any time (which is what often happens).
According to Eurocontrol, it should be possible in this case to delay the flight plan to coincide with the slot. Then you can adjust your morning pace.
I think that if you get a slot and you don’t want it to come forward anymore, it is better to change your RFI status in the CFMU system.
By default you get slot improvements allocated automatically, but you can change this to SWM. Then CFMU proposes an improvement and it is up to you to accept or not.
Over the last 2 years years I had a couple of delays from Basel to Mallorca, due to ‘route congestion’ as the Swiss apparently called it. Well, it can’t be that busy at FL100 so I guess it had more to do with the fact that my route took me over Geneva and they were busy with some congress or lots of jets coming in for skiing holidays.
Whenever a thing like this happens I try to get someone on the line, preferable OPS at the departure field to try to get a better EOBT. At the most recent occasion the whole thing threatened me to make me miss the closing time of Son Bonet so I used that as an argument. I must say that they sounded receptive to that problem and promised me to do their utmost, and got me out almost without delay in the end. Helpful people..
It was CAVOK. I was thinking of other scenarios like asking for a reroute west, into France, or request a Zulu departure and (once in the air) negotiate my way into the system. Any ideas on whether that would have worked?
airways wrote:
I think that if you get a slot and you don’t want it to come forward anymore, it is better to change your RFI status in the CFMU system.
By default you get slot improvements allocated automatically, but you can change this to SWM. Then CFMU proposes an improvement and it is up to you to accept or not.
That’s a bit too technical for pilots… you can just delay your plan to the allocated slot time to lock it down. If I think I might get a slot, I like to file earlier than I plan to depart and see how the slots evolve. You can always delay. If I file a 0600Z departure and get a 0700Z, that is better than filing a 0700Z departure and then get a 0800Z slot
boscomantico wrote:
But then, slots don’t make much sense, do they? if everybody gets shifted back by 30 minutes, the traffic will not be less, will it?
The internal workings on this mechanism are very simple. The airspace is organized in sectors which are under ATC control. Each sector has a certain capacity, i.e. concurrent aircraft. The capacity can be changed by ATC at any time and in case of a strike (i.e. every other week in France) it’s significantly reduced. In case of the ash cloud delusion, all sectors where set to capacity 0. Once a sector reaches its capacity limit, it becomes subject to “flow control” which means slots are generated by the system automatically to make sure that based on the operational model, the maximum number of aircraft is never exceeded. It’s a very dynamic thing because different operators take different measures. Somebody might cancel/refile, somebody else delay, the wind forecast model gets an update, etc.
boscomantico wrote:
this might take me “to the end of the cue” again, but that didn’t happen – immediately received the same slot time as before
That means that the queue was very short. It’s difficult to know in advance so risky business to cancel or bring forward (which includes a cancel operation).
From our statistics, Switzerland is the worst by far. However, we also have a lot of activity in Switzerland so getting meaningful statistics is hard but it looks like it’s the most affected country. I guess their limit is around 2 aircraft over the country…
Sometimes you can derive the location of the slot from the slot ID. LSxxxx is Switzerland. Earlier this year I flew from Belgrade to Stuttgart and I got a 2h slot that I could not get rid of. Eventually I noticed that it came from Croatian ATC and my route touched a tiny bit of the Zagreb FIR. I changed it to avoid that 20NM and voilà, no more slot. Another trick is to put in a VFR leg for the affected area.
