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Eurocontrol Flight Planning FAQ: Slots, Delays And What To Do

 |  10 February 2014

At RocketRoute.com we are often asked the same questions in regards to standard flight planning procedures in Europe we thought we would gather some FAQ key responses:

When do I file a Flight Plan?

Official answer: Not later than 3 hours before Estimated Off Block Time (EOBT). Often this is impractical. Especially as ICAO has no direct messages to bring a flight plan forward often requiring planners to cancel and refile (now that planners are no longer allowed to send REA messages). So in reality 20 to 30 minutes is an operational minimum. This will allow enough time for the CFMU readressing to kick in and the messages to be distributed to the affected towers and ATC units. In some airports you will find that the tower gets messages from us near instantaneously.

What happens next?

You will get either: ACK meaning the flight plan has been accepted and complies with the requirements, at least those known to CFMU. A good example of this is IFR flights below FL090 in the London TMA which is a limitation not implemented by NATS with CFMU but regularly leads NATS to ask for a call to the planner. Why NATS just does not put that in the RAD we do not know.

You can also receive a MAN (This means there is a possible error or at least the automated system could not process it but it also did not find an obvious error. So it lands on an operators desk at CFMU who will now MANually look at it. This means BE PATIENT!! We have crews frantically cancelling and refiling and sending RQP messages whilst the MAN process is going on causing havoc to their flight plan. Then giving up in despair blaming us or Eurocontrol. To make it clear after a MAN you MUST WAIT until it is either confirmed ACK or REJ for rejected. This usually takes anywhere from 5 minutes to 30 minutes. If nothing has happened after that call our help desk or call the CFMU help desk directly with your aircraft registration or flight number ready. The numbers are listed at the bottom of this blog. After manual processing you will get either an ACK or REJ automatically.

How do I revise my FPL?

Either send a Delay (DLA) or a Change (CHG) message. The DLA message allows you to delay your flight up to 20 hours. If you need a longer delay you must cancel and refile. The CHG message is used to update information such as adding a slot number RMK/ASL1223456 changing CREW name, changing aircraft registration REG/DALIA if an aircraft has gone tech and you are using flight numbers etc.

Change, I do not recommend sending a change message to change a routing or any significant part of the flight plan unless you have reverified correctness with CFMU beforehand. It just leads to too many REJ messages, so if you are changing routes just cancel and refile. If you had a SAM (See below) you will change these anyway by rerouting

When do I have to send a DELAY message?

Send a DLA for any change of EOBT greater than 15 minutes. However, If you received a SLOT and were given a new Calculated Take Off Time (CTOC) please do not delay your flight as this has already been included by CFMU.

When can I get a Slot Allocation Message (SAM)?

Any time the powers at Eurocontrol want to. This is based on what their computers tell them how busy the airspace is. Please do not confuse this with reality as all you aircrews in the lower flight levels know. Think Volcanic ash on a sunny day. You will receive a SAM at the earliest 2 hours before your EOBT. This message will include a so called new CTOT (Calculated Take Off Time). So make sure we can reach you on your mobile as otherwise you will miss this vital information

The message will often also include a REGUL number referring to the regulation that caused you to receive a slot. The exception to the 2 hour before EOBT rule is that when you file and the computer realises that a regulation will effect you anyway, in which case you will get a SAM immediately.

Now here is the important bit; after you SLOT message the computer keeps checking capacity and very often changes your SLOT back closer towards your original EOBT. This usually happens in steps so you start with 45 minutes delay then 20 then 15 the 5 minutes. So be ready to start close to your EOBT and keep your mobile on as we will send you an SMS with updated SLOT messages. These updates will take the form of a SRM or SCM

What happens if I update my EOBT after I have received a slot?

Basically you loose your existing SLOT and the next available slot will be issued (usually later in my experience). To avoid a substantial delay, especially at busy times, it is best to update your EOBT early and then not change it at all close to departure time. I once had a slot in Amsterdam with a 45 minute delay and was inexperienced enough to refile causing myself a 2 hour delay. You live and learn!

What happens if my SLOT changes?

You will receive a Slot Reallocation Message (SRM) with a new CTOT. This happens automatically when better slot has been found for you or if a regulation has changed or if you delayed your flight plan. This means you have to monitor your SMS on your mobile phone as we keep forwarding them to you and you better be ready to depart if it suddenly comes forward again.

What action do I take if I cannot comply with my slot?

Well, you best send a DELAY or CANCEL message so the SLOT can be reused and to minimise your risk of further delay. If you miss your slot please immediately send a Delay message. You will then received either another SRM or a Slot Cancellation Message (SCM).

What do I do if I get an SLC?

Good news your slot has been cancelled. You’re good to go on your original EOBT, hence you need to monitor your mobile phone for messages from us with SLOT updates.

Can I ‘freeze’ my slot?

No. If you do send a Delay message please observe this formula to avoid losing you slot: New EOBT must not be later than CTOT minus taxitime minus 10 minutes.

Example: EOBT 1000, CTOT 1100, but the flight cannot go off blocks until 1025. The taxitime is 15 minutes. Calculation :1100 – 15, minus 10 = 1035.The new EOBT must be earlier than 1035,in order not to trigger a revised CTOT.

Can I send a READY (REA) Message when I am ready to go?
No, this is no longer possible. Only ATC is now allowed to do this. I guessed the airlines abused it once to often and its now taken away from us.

CFMU Help desk numbers

There are two help desks. One in Brussels at +3227451950 and one in Bretigny +33169881750. Do not be afraid to call the people there. They are very friendly and helpful and unlike some local “towers” really know their stuff on flight planning. I rate them very highly and they have helped me in many a tight spot.

Reference documentsCFMU ATFCM USER MANUAL

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