We flew an IFR departure from Schwabishe Hall (EDTY) today that raised a few questions. It’s an excellent GA oriented airport, self-service fuel, friendly and efficient staff etc. with a very scenic and attractive town only a few minutes away.
It has AFIS rather than ATC, so after co-ordination IFR arrivals and departures with the area radar controller at Langen, AFIS announce to everybody on frequency that an IFR movement is taking place.
I filed using Autorouter (excellent system that just keeps getting better). EOBT time was 08:00Z. The briefing pack stated a time of 08:05 on the subsequent page, which I presume is the expected take-off time. Even in a small place like this it takes me more than 5 minutes from starting taxi to take-off, I think 10 is more realistic. The AFIS was pretty keen for us to meet our slot time.
07:50 request clearance
07:52 Clearance delivered (after a phone call from AFIS to Radar)
07:57 Startup
08:00 Are you ready to taxi?… You were allocated a slot time of 45…Last information from Radar was that you should depart at 08:05
08:10 Departed
So my questions are…
1) Does autorouter specify the 5 minutes from EOBT to take-off? Otherwise where does that come from?
2) Should we have received some notification of our earlier than filed slot time (AFIS did try to contact us prior to my turning the radio on)?
3) What are the time constraints of the slot time issued by Radar?
4) What happens if we miss our slot
Very strange. There should be no slot earlier than your EOBT.
2) In your ATC flight plan, you can enter a mobile number and/or an email address. You will then get your slot messages either as text message or by mail.
3) Slot times (Eurocontrol at least, airport slots can be different) are -5 / +10 minutes. So earliest airborne time five minutes before your slot, latest is ten minutes after.
4) ATC will not release you. The AFIS will inform you about that. If you depart anyway from a VFR only airfield, they can refuse your IFR pickup. If you depart from an uncontrolled airfield like EDTY with an established IFR departue outside your slot time, you can fly normally. A few days later, you will receive a letter asking you for an explanation. If that is not good enough, some kind of legal prosecution will follow. Luckily I have no personal experience with that.
1) Does autorouter specify the 5 minutes from EOBT to take-off? Otherwise where does that come from?
That is a sensitive topic at Eurocontrol. In the past, some airlines have used unrealistic taxi times to move themselves ahead of the queue in the morning rush. Eurocontrol have addressed this by compiling a list of average taxi times per aerodrome (and runway in use) and publishing that to flight plan service providers like autorouter. We therefore use the recommended value from Eurocontrol
2) Should we have received some notification of our earlier than filed slot time (AFIS did try to contact us prior to my turning the radio on)?
Your EOBT was 0800Z per your filed flight plan and then a slot was issued by Langen for 0805Z (so called CTOT). In the future we will send you an email and optionally SMS on all slot allocations.
3) What are the time constraints of the slot time issued by Radar?
As precise as possible, Eurocontrol give you -5 to +10 minutes on the CTOT.
4) What happens if we miss our slot
You will have to request another slot.
Thanks for the detailed and helpful replies
I doubt very much the AFIS would have released me for IFR departure after the slot time had expired. I guess I would have to shutdown and refile. At least I know the limits now.
I did find autorouter really easy to use; the additional notifications will make this even better.
Could the time constraints of the slot be added to the briefing pack?
I forgot to mention that the initial clearance on the ground included a couple of direct shortcuts which optimised the routing. It was already pretty good.
Indeed, the autorouter is superb tool.
I think it just lacks the possibility to read the AFTN messages related to your FPL to be perfect.Two weeks ago I filed an IFR FPL via eurofpl and I got a slot. The fact that eurofpl displays AFTN messages really helped me to understand why I got a CTOT.
Could the time constraints of the slot be added to the briefing pack?
At the time of filing and briefing pack generation, the slot is not known. It will be assigned at some point after the plan was filed which means it could be in the briefing pack update but the slots can change many times. It is not uncommon in some not so well managed places of Eurocontrol land for a slot to change 15 times and in the end disappear. This has to be handled with email/SMS.
Overall, slots are very rare for small GA.
I think it just lacks the possibility to read the AFTN messages related to your FPL to be perfect.
Two weeks ago I filed an IFR FPL via eurofpl and I got a slot. The fact that eurofpl displays AFTN messages really helped me to understand why I got a CTOT.
Very soon you will get all slot messages and they will contain additional information for the more tech savvy users to understand where they come from. However, why do you want to read the whole log? It could easily be done (we have it in the admin interface already) but I fear it would confuse 90% of the users. I’m not a fan of cryptic specialty features that only benefit very few users but confuse the rest… Suggestions welcome.
Keep it simple as it is 
Sorry for the novice question but what slot time are we talking about? It is not the airport slot, so I assume it is a kind of slot in the IFR system of Eurocontrol. However in my limited IFR experience (currently training) I have never heard about that slot. I heard about the CTOT which obviously is something Eurocontrol calculate but they don’t give it to me or inform me about it. I’ve only flown IFR between ATC controlled airports in Germany, Switzerland and France and being +/- 15 minutes of the estimated block off time was never a problem.
CTOT is a synonym for slot:
Calculated Take Off Time (CTOT) – The time provided by the Central Flow Management Unit (CFMU), taking into account the European Civil Aviation Conference (ECAC) ATC flow situation, that an aircraft has been calculated to take off. The CTOT, also known as the ATFM ( Air Traffic Flow Management) slot, has a tolerance of – 5 to +10 minutes
As I said, they are rare for GA but when you get them, you have to respect them. They are issued by sectors and transmitted to Eurocontrol where they get forwarded to the parties involved. Normally your tower/delivery at your start aerodrome would inform you but in the case of using a computerized flight plan software provider (Eurocontrol speak for autorouter), you can receive the information from there as well, typically as an email or SMS.
If you do not have a CTOT assigned, you can use the standard -15/+30 minutes.
Thanks achimha. I never got one like that and I am almost at the end of my training. I always wonder how one learns all those additional details that you never meet during the instruction time and how many times you get fined or at least frowned upon before you know them.
