Expired CTOT during taxi
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Expired CTOT during taxi
In the event that unforeseen circumstances during taxi cause a flight to miss its CTOT before being ready for departure , how is that flight normally treated? ( at least here in Europe ? )
Do you allow the flight to depart assuming it is expected to be ready for departure very soon after the exparation?
do you allow the pilot the remain at some holding point to file a delay message ? ( btw will it be treated favorably if it is know that it’s taxing ?)
Is the flight forced to return to a parking position ?
Do you allow the flight to depart assuming it is expected to be ready for departure very soon after the exparation?
do you allow the pilot the remain at some holding point to file a delay message ? ( btw will it be treated favorably if it is know that it’s taxing ?)
Is the flight forced to return to a parking position ?
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I have been on a flight with a CTOT and due to a slow vacating aircraft, we had to wait for another arrival before we could depart. It was 1 min past the +10 CTOT window and we were told that we had missed our slot (through no fault of our own), so had to taxi off and wait out for the new CTOT to be issued.
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NM has been so busy recently with all the weather and Frog strikes that they did/could not pick up the phone anymore. Meaning no slot extensions via the unbureaucratic way but delay messages via company instead with the ensuing even worse slot. Sometimes though, the bits and bytes are already airborne with the aircraft following a few minutes later. 
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Negotiation with UKFMP/Brussels is still available these days but if they say no it's a slot missed messaged and time to cross your fingers.
They are usually great at being flexible however they have to cater for many phone calls they get from many airports who want CTOT extensions, it's not always possible.
They are usually great at being flexible however they have to cater for many phone calls they get from many airports who want CTOT extensions, it's not always possible.
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As most ‘regulated’ flights in Europe are Public Transport flown by commercial pilots employed by Airlines operating under an AOC, I find it hard to believe their AOC allows the captain to insist on departing if he or she has missed their slot.
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I think at an ATC unit where no take-off clerance is given (due to expired CTOT) the captain taking off without one means the ensuing paperwork will not focus on the bust CTOT...
To answer the original question.
Depends on circumstance, the first step is often to put the question to the FMP (who in turn will negotiate with the NM) to see if there is any chance of moving it by a few minuts. If it's not a complicated situation they can often extend it or generate a new slot within short notice. This depends on the circumstance, if there is only one regulation involved with fairly low delays (and the network as a whole runs smoothly) they seem to be pretty good at working some magic. If the flight is subject to several regulations or delays are very high then quite often there is nothing they can do manually, at least not straight away.
The flight can not depart outside of the CTOT, so it will not just be ignored like it may have been in "the old days".
If there is scope for it (depends a bit on runway configuration and airfield circumstances) the flight tends to remain at the runway. This also makes it easier to improve the CTOT as we can tell the computer that the taxi time is very short. If it returns to stand then the taxi time is obviously much longer. Saying this I have seen aircraft having to return due to fuel issues, after pushing to expect to make a slot (which they were) and a combination of CTOT moving forward and a technical issue meant they just missed it. In this case the CTOT is less of a concern as the flight has to return to refuel, the flight plan is then suspended and once a new EOBT submitted a new CTOT generated, in that circumstance it practically turns into a normal departing flight of stand.
There is no advantage to send a delay during taxi. In fact the later you send it the worse you risk the CTOT getting, normally the least delay is incurred by filing the delay as early as possible. But the computer doesn't know if the aircraft is under taxi or on a stand when the delay is filed so it will assume the "standard" scenario of aircraft on a stand. For ready messages though the taxi time is adjusted by ATC to make sure it's as realistic as possible as a shorter taxi time increase the chances of the CTOT improving.
Now all of this is based on a non-CDM airport, so what would happen at an airport running CDM I don't know, but hopefully someone else can explain that scenario.
In the event that unforeseen circumstances during taxi cause a flight to miss its CTOT before being ready for departure , how is that flight normally treated? ( at least here in Europe ? )
Do you allow the flight to depart assuming it is expected to be ready for departure very soon after the exparation?
do you allow the pilot the remain at some holding point to file a delay message ? ( btw will it be treated favorably if it is know that it’s taxing ?)
Is the flight forced to return to a parking position ?
Do you allow the flight to depart assuming it is expected to be ready for departure very soon after the exparation?
do you allow the pilot the remain at some holding point to file a delay message ? ( btw will it be treated favorably if it is know that it’s taxing ?)
Is the flight forced to return to a parking position ?
Depends on circumstance, the first step is often to put the question to the FMP (who in turn will negotiate with the NM) to see if there is any chance of moving it by a few minuts. If it's not a complicated situation they can often extend it or generate a new slot within short notice. This depends on the circumstance, if there is only one regulation involved with fairly low delays (and the network as a whole runs smoothly) they seem to be pretty good at working some magic. If the flight is subject to several regulations or delays are very high then quite often there is nothing they can do manually, at least not straight away.
The flight can not depart outside of the CTOT, so it will not just be ignored like it may have been in "the old days".
If there is scope for it (depends a bit on runway configuration and airfield circumstances) the flight tends to remain at the runway. This also makes it easier to improve the CTOT as we can tell the computer that the taxi time is very short. If it returns to stand then the taxi time is obviously much longer. Saying this I have seen aircraft having to return due to fuel issues, after pushing to expect to make a slot (which they were) and a combination of CTOT moving forward and a technical issue meant they just missed it. In this case the CTOT is less of a concern as the flight has to return to refuel, the flight plan is then suspended and once a new EOBT submitted a new CTOT generated, in that circumstance it practically turns into a normal departing flight of stand.
There is no advantage to send a delay during taxi. In fact the later you send it the worse you risk the CTOT getting, normally the least delay is incurred by filing the delay as early as possible. But the computer doesn't know if the aircraft is under taxi or on a stand when the delay is filed so it will assume the "standard" scenario of aircraft on a stand. For ready messages though the taxi time is adjusted by ATC to make sure it's as realistic as possible as a shorter taxi time increase the chances of the CTOT improving.
Now all of this is based on a non-CDM airport, so what would happen at an airport running CDM I don't know, but hopefully someone else can explain that scenario.
If the captain insists on going, ATC or AFIS or AGCS cannot stop him/her.
2 s
I think at an ATC unit where no take-off clerance is given (due to expired CTOT) the captain taking off without one means the ensuing paperwork will not focus on the bust CTOT...
The flight can not depart outside of the CTOT, so it will not just be ignored like it may have been in "the old days".
The flight can not depart outside of the CTOT, so it will not just be ignored like it may have been in "the old days".
Has this rule been changed?
At an ATC airfield, it is the captain's decision to depart outside his CTOT; if there is no 'local' traffic to conflict, ATC cannot withhold takeoff clearance but they can advise him he is outside his CTOT and that he will be reported.
AFIS and A/G can only advise him he is outside his CTOT and report the occurence.
I've got direct experience of this. Aircraft inbound to Farnborough from Crete, but his CTOT meant he would be unable to land at Farnborough before closing time (10pm - no flexibility or discretion allowed except in emergency)
Waited for his CTOT and then sent a 'request dep' message.
Message came back he had departed on his CTOT, so I discussed it with the FBO and we decided to close the airfield at 0915 (which ATC are allowed to do after consulting the FBO if there is no traffic scheduled).
Next day I went in to work to discover that Iraklion had disregarded his CTOT and allowed him to depart on his original filed EOBT (over an hour prior to his CTOT) so he would have got to us just before closing
Brussels, instead of checking if he was airborne, had quoted us his CTOT as a 'live' departure time but we didn't realise it was Brussels replying to the request; Iraklion never did reply.
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I think the original poster wanted to know what happens these days, not what happened 45 years ago on one ATCOs ADC course and not what happened 7 years ago at Farnborough, there’s an ‘Aviation History and Nostaglia’ area on pprune for that.
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Some (actually most) ATC units are very helpful and will try and (legitimately) get you a few minutes of slack. They will normally also allow the last few seconds of the Slot to be used, like LBA did for us yesterday. But you have to do your bit. And that means “Ready” when you actually are, rolling when you are cleared etc. But they do have limits. Typically you will be kept informed and together you can work out something that doesn’t waste loads of fuel or you taxiing around in circles. But and there are places and times when you hear “You have missed your Slot. You will return to the gate” or something similar. MUC will do that with pleasure, you can almost hear the glee in their voices. You are No. 6 to taxi, you WILL be No. 6 to depart, there will be eight arrivals ahead of you, you have allowed 20-25 minutes taxi... Not their problem!
PM
PM
ATC CANNOT WITHOLD A CLEARANCE FOR OTHER THAN TRAFFIC REASONS was drummed into us on my ADC course some 45 years ago.
Has this rule been changed?
At an ATC airfield, it is the captain's decision to depart outside his CTOT; if there is no 'local' traffic to conflict, ATC cannot withhold takeoff clearance but they can advise him he is outside his CTOT and that he will be reported.
AFIS and A/G can only advise him he is outside his CTOT and report the occurence.
I've got direct experience of this. Aircraft inbound to Farnborough from Crete, but his CTOT meant he would be unable to land at Farnborough before closing time (10pm - no flexibility or discretion allowed except in emergency)
Waited for his CTOT and then sent a 'request dep' message.
Message came back he had departed on his CTOT, so I discussed it with the FBO and we decided to close the airfield at 0915 (which ATC are allowed to do after consulting the FBO if there is no traffic scheduled).
Next day I went in to work to discover that Iraklion had disregarded his CTOT and allowed him to depart on his original filed EOBT (over an hour prior to his CTOT) so he would have got to us just before closing
Brussels, instead of checking if he was airborne, had quoted us his CTOT as a 'live' departure time but we didn't realise it was Brussels replying to the request; Iraklion never did reply.
Has this rule been changed?
At an ATC airfield, it is the captain's decision to depart outside his CTOT; if there is no 'local' traffic to conflict, ATC cannot withhold takeoff clearance but they can advise him he is outside his CTOT and that he will be reported.
AFIS and A/G can only advise him he is outside his CTOT and report the occurence.
I've got direct experience of this. Aircraft inbound to Farnborough from Crete, but his CTOT meant he would be unable to land at Farnborough before closing time (10pm - no flexibility or discretion allowed except in emergency)
Waited for his CTOT and then sent a 'request dep' message.
Message came back he had departed on his CTOT, so I discussed it with the FBO and we decided to close the airfield at 0915 (which ATC are allowed to do after consulting the FBO if there is no traffic scheduled).
Next day I went in to work to discover that Iraklion had disregarded his CTOT and allowed him to depart on his original filed EOBT (over an hour prior to his CTOT) so he would have got to us just before closing
Brussels, instead of checking if he was airborne, had quoted us his CTOT as a 'live' departure time but we didn't realise it was Brussels replying to the request; Iraklion never did reply.
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As ATC in an all-singing, all-dancing, electronic trickery tower, we cannot enter a DLA message for an aircraft once it is taxying.
It’s a pain tbh. If it becomes clear during taxy that, for some unforeseen reason, the aircraft cannot now make the CTOT window then it requires telephone co-ordination. If that can’t be achieved (workload at either end of the phone) then it’s either remote hold, if possible (fuel/airport infrastructure), while ATC tries to get co-ordination for a new CTOT or it’s a return to stand and send DLA electronically (in which case aircraft will go to the back of the queue) - either way it’s additional workload.
Rest assured that ATC want to get you away in CTOT window - and will try to do that as best they can - and will try to get some form of extension where possible under those circumstances - it’s a whole lot better for everyone concerned (...but please, if there is a foreseen reason why you cannot be ready for departure at the holding point at CTOT - not CTOT +9mins - file an amended EOBT as early as possible...give us all a fighting chance!).
It’s a pain tbh. If it becomes clear during taxy that, for some unforeseen reason, the aircraft cannot now make the CTOT window then it requires telephone co-ordination. If that can’t be achieved (workload at either end of the phone) then it’s either remote hold, if possible (fuel/airport infrastructure), while ATC tries to get co-ordination for a new CTOT or it’s a return to stand and send DLA electronically (in which case aircraft will go to the back of the queue) - either way it’s additional workload.
Rest assured that ATC want to get you away in CTOT window - and will try to do that as best they can - and will try to get some form of extension where possible under those circumstances - it’s a whole lot better for everyone concerned (...but please, if there is a foreseen reason why you cannot be ready for departure at the holding point at CTOT - not CTOT +9mins - file an amended EOBT as early as possible...give us all a fighting chance!).
ATC CANNOT WITHOLD A CLEARANCE FOR OTHER THAN TRAFFIC REASONS was drummed into us on my ADC course some 45 years ago.
Has this rule been changed?
Has this rule been changed?
2 s
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C.M., I can only comment on the procedures in MUC as a CDM- Airport.
First we have to clear up a common misunderstanding. The CTOT is the time the aircraft has to be at the runway.
The slot window -5/+ 10 is a time for ATC only, to handle flights with a CTOT more flexible (for example those unforeseen circumstances you mentioned)
But in reality this slot window is often used by the airline to compensate the delay they have and to avoid a delay message ( or a new target offblock time
at a CDM airport).
If an aircraft missed the slot during taxi we generate an updated target take off time which triggers a new CTOT. ( CDM airports have a automatic data exchange
with the NMOC in Brussels ). If we are not pleased with the received CTOT we call NMOC on landline and ask for improvement. Of course there are sometimes regulations that cannot be improved. Then the flight will stay close to the runway and if necessary shut down the engines there. However this worst-case-scenario
is extremely rare.
By the way, flights with a urgent slot will prioritized if circumstances permit. Unfortunately in the last weeks/months almost every flight had a slot and this
makes it a lot harder to save the day for the urgent ones.
First we have to clear up a common misunderstanding. The CTOT is the time the aircraft has to be at the runway.
The slot window -5/+ 10 is a time for ATC only, to handle flights with a CTOT more flexible (for example those unforeseen circumstances you mentioned)
But in reality this slot window is often used by the airline to compensate the delay they have and to avoid a delay message ( or a new target offblock time
at a CDM airport).
If an aircraft missed the slot during taxi we generate an updated target take off time which triggers a new CTOT. ( CDM airports have a automatic data exchange
with the NMOC in Brussels ). If we are not pleased with the received CTOT we call NMOC on landline and ask for improvement. Of course there are sometimes regulations that cannot be improved. Then the flight will stay close to the runway and if necessary shut down the engines there. However this worst-case-scenario
is extremely rare.
By the way, flights with a urgent slot will prioritized if circumstances permit. Unfortunately in the last weeks/months almost every flight had a slot and this
makes it a lot harder to save the day for the urgent ones.
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although now the T-Manager usually has to get Brussels to approve it. Unless it’s a UK reg.
we’d never make the aircraft return to stand.
worst ways we will update then plan, re ready message it and find somewhere for it to wait.
1 minute after the CTOT, I’d just forget how to count or accidentally mark the strip airborne...
