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CTOT nonsense

boscomantico wrote:

You just wait until your slot time minus 15 minutes, start up, taxy and take off at CTOT minus 5.

That’s what I do.

boscomantico wrote:

which still creates a lot of undue stress in the cockpit, with all the variables of taxy time, pre-takeoff checklists, traffic, etc.

It does although I train myself to be resilient but when it includes several means of transportation to reach the airport, it’s not easy not to be stressed. Yesterday, I took bus to get to Copenhagen main train station, followed by train to Roskilde, followed by taxi to EKRK. Luckily in Denmark public transport works precisely on schedule and planned 1 hour of travelling from apartment to airport lasted 55 min. Something like that would be absolutely impossible in Croatia.

LDZA LDVA, Croatia

Reviving this older thread. Flying a long route through France I’ve noticed that now nearly every IFR flight plan within France seems to get a CTOT. The way it happens is always the same, you file an EOBT at for example 10:00 and you get a CTOT of 10:04 or 10:06. Look at the message and you’ll see that the difference between the filed EOBT and the CTOT is always exactly equal to the estimated taxi time (that’s in the same message). So basically they’re telling you to leave blocks at exactly the EOBT and then taxi as fast as the computer thinks you would taxi at that field. To take off within -5/+10 of the time they think you would take off with such a taxi time.

Why is France doing that? It makes no sense to GA at all, the taxi times are quite random (some airports 4 minutes, some similar sized ones you get 10 min), and it makes the departure a lot more inflexible than without the CTOT. While in the end you’re going to be flying around as the only traffic at FL080 – FL150 with no impact on anyone.

Last Edited by Thomas28 at 19 May 21:32

I get load of these 5min CTOT, the reason is usually sector 100nm down the line rather than departure sector, if you have AutoRouter it usually give you the congested sector and reason, in my case, reasons are rarely departures but some busy points around Paris TMA

Yes it’s inflexible and usually defeat the purpose: I am stuck on pavement until 1255 instead of departing early or late while managing my flight to make say BRY VOR at 1338 FL80 (what CTOT wants in 1st place)

When I comply with these high precision CTOT, I get load of vectors, delays and shortcuts:

  • Either, I don’t even fly near BRY VOR, or
  • I fly near BRY VOR but at 1348 or 1328

I am not sure why it never get it right? maybe has to do with bad aircraft & traffic models or c*** routings? or likely CTOT only work to regulate sectors on average? while they never work on each flight (like thermodynamics, it works in the big scheme of things LOL)

Taxi time at uncontrolled airfields (and some require phone call for IFR startup) varies a lot between 1min and 25min: there were 8 aircraft in circuit yesterday on auto-info including someone who was practicing rejected takeoff with no ATC…

Last Edited by Ibra at 19 May 23:26
Paris/Essex, France/UK, United Kingdom

Exactly as you describe, it doesn’t seem to work for GA traffic to try to manage by 5 minutes with a taxi-time variance of +/- 10 minutes. We got these 5 minute CTOTs around LFOP, LFBH, LFOT, LFRN, LFQA and even into LFRM and LFLA which at the times we were there were both uncontrolled air-to-air type fields.

I’ve never seen this 5 min type of CTOT thing happen in the Netherlands, UK or Germany. Is it a French specific thing or was I just very unlucky to run into them all around France?

CTOTs happen around Amsterdam as well, but they don’t tend to be 5 minutes. It’s more like 45 minutes or an hour if you are trying to leave or arrive during a big push of airline traffic with weather conditions that reduce capacity (fog or bad wind direction).

Last Edited by Thomas28 at 20 May 21:13

Yes most of the time it’s barely enforcing 5min for taxi and indeed it happens very often in France, however, the error being thrown happens 100nm away which is very odd and fishy…I never had CTOT slot in UK, ever ever, even when flying in most busy corner: 5 frequencies, 5 transponder codes and 10 vectors before getting first direct, I had CTOT in Germany, they were “real 40min delays” rather than “5min slot forcing your original plan -5/+10”

If you are not happy with getting 5min gap between EOBT or CTOT, you can set TAXI:15 or TAXI:10 in RMK to avoid rushing and get some headroom (what I do in Pontoise, Toussus, Melun as they are busy and you can be stuck depending on runway in-use, weather, traffic if my parking spot is miles away, plus the slots are well enforced/policed)

Last Edited by Ibra at 20 May 21:58
Paris/Essex, France/UK, United Kingdom

Thanks! I’ll try the TAXI in RMK next time I’m doing a lap of France. Indeed nice to know you have time instead of risking the flightplan being suspended because you miss the takeoff time.


AIUI these slots are more about pilots sticking to the times they have given in their flight plan.
It is very rare in France that if you meet your EOBT that you will be penalised for not making your CTOT -5/+10 and ATC has some room for manouver. ATS are having to be a little more time conscious at the moment because of the industrial action. The problem doesn’t necessarily reflect on them taking industrial action, which they have scheduled for, but more to do with the fact that controllers are late for work due to manifestations on the transport network. It shouldn’t really be a problem as long as you call for taxi either on time or if necessary a little earlier if you feel you need more than 15minutes from EOBT to CTOT. Never needed it myself.


ATC are not permitted to let you depart once you go outside the CTOT tolerance. Even Shoreham EGKA will not allow it. I heard that there would be some comeback or sanction if they did allow it.

But ATC can make a phone call to some number which can authorise it.

I had this at LFMT recently, for example.

Shoreham EGKA, United Kingdom

gallois wrote:

It is very rare in France that if you meet your EOBT that you will be penalised for not making your CTOT -5/+10 and ATC has some room for manouver.

My problem was with the -5 limit not the +10, we were mostly very on time on this trip. Normally being 15 min early for the filed EOBT is not a problem at all, startup approved and off you go. But with a CTOT 5 min after your filed EOBT and an official taxi time of 5 minutes, you can’t technically start earlier than EOBT. We still got most units to approve startup about 5 minutes earlier than EOBT for “engine warmup” but they refused doing that 15 min before EOBT due to the CTOT.

It sounded like they also don’t have the departure clearance at that point. One unit for example responded “technical startup approved, I will call you back for official startup”. I interpreted that as an OK to start the engine and warm up, but they would not press the magic button on the computer to get our clearance and go.


Yes, that is a very French thing. They call it “mise en route”, and it sort of starts your IFR clearance process.

I hate slots, too. Even if the 15 minute window happens to fall exactly where you need it, it causes undue stress. And for what? For AI’s sake, nothing more.

Last Edited by boscomantico at 21 May 19:16
Mainz (EDFZ) & Egelsbach (EDFE), Germany
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