Frequently Asked Questions (FAQ) on network operations

ATFCM Contingency - What will the NM do if its system fails?

In the event of the system failure a contingency procedure will be started and instructions will be issued by the NM.
To permit resumption of slot allocation following recovery, AOs should continue to send flight plans and flight plan update messages to IFPS (Integrated Initial Flight Plan Processing System) throughout the whole period of operation of the contingency plan.
Depending on the level of severity of the failure, AOs may expect significantly higher delays than normal.

Call Help Desk - When do I contact the Central Flow Help Desk?

If your delay is significantly above average.
If you have a critical ATFCM problem on the day of operations

Change status - Can I send an REA (Ready Message (sent only by ATC)?

No. Only ATC (TWR or FMP) can send an REA.

Change status - How do I change status of my flight?

By sending :

  • αn SWM (SIP Slot Improvement Proposal) Wanted Message), if you were in RFI (Ready/Request For (direct) Improvement ) status
  • or αn RFI, if you were in SWM status
Change status - What are my options?

Default status for AOs is RFI (Ready/Request For (direct) Improvement), i.e. if an improvement is available you would receive it via an SRM (Slot Revision Message).
Another status is SWM (SIP Slot Improvement Proposal) Wanted Message) , where improvements are proposed by an SIP.
Alternatively, you may request the ATC at the departure aerodrome to change your status by sending an REA (Ready Message (sent only by ATC).

FPL updates - How do I revise my FPL?

Send a DLA/CHG.

FPL updates - When do I file an FPL?

Not later than 3 hours before EOBT. You will get either:
ACK (FPL accepted).
MAN (errors in FPL; after manual processing you will get either ACK or REJ) REJ (FPL rejected).
REJ (FPL rejected).

FPL updates - When do I notify a delay?

Send a DLA/CHG for any change of EOBT (Estimated Off Block Time) greater than 15 minutes. However, do not update EOBT as a result of delay given by CTOT (Calculated Take-Off Time).

Low visibility - How do I specify my RVR (Runway Visual Range)?

Either by an FPL or CHG, or by sending an FCM (Flight Confirmation Message).

Low visibility - What will the NM do in the event of low visibility at my destination airport?

Suspend flights with unknown RVR (Runway Visual Range) capability.
Delay flights with insufficient RVR capability until the end of the low visibility period.
Slot flights with sufficient RVR capability within the low visibility period.

Non availability of aerodrome or airspace - What may I expect if an aerodrome becomes non-available?

The NM will assess the duration and nature of the non-availability and :
Accept the FPLs in IFPS (Integrated Initial Flight Plan Processing System) and regulate them and :

  • either suspend flights in the event of a long non-availability (more than one hour),
  • or delay flights to arrive or depart when the aerodrome is opened
Non availability of aerodrome or airspace - What may I expect if an airspace becomes non-available?

The NM will assess the duration and nature of the non-availability and :
either close the airspace in the ENV database and consequently reject all relevant FPLs,
or accept the FPLs and regulate them and :

  • either suspend flights in the event of a long non-availability (more than one hour)
  • or delay flights to arrive or depart when the airspace is available.
Rerouteing - How can I reroute my flight?

Send a new route via a CHG (Change) or CNL (Cancel) and RFP (Replacement Flight Plan), or use AOWIR (Aircraft Operator ‘What-If’ Re-route) if you have access to ATFCM CHMI/NOP (Network Operation Portal).

Rerouteing - What are my options?

Investigate alternative routes that avoid congested areas. Refer to the daily network news for suggestions and use the AOWIR (Aircraft Operator ‘What-If’ Re-route) if available.
Consider filing an FPL at an alternative flight level. It is important that pilots are briefed that flight levels in FPL have been filed so as to avoid an ATFCM regulation.

Slot - Can I ‘freeze’ my slot?

No. However, if the CTOT (Calculated Take-Off Time) received is acceptable, then a DLA (Delay) message should be sent to IFPS (Integrated Initial Flight Plan Processing System) using the following formula:
New EOBT (Estimated Off Block Time) must not be later than CTOT minus taxi time minus 10 minutes. Example: EOBT 1000, CTOT 1100, but the flight cannot go off blocks until 1025. The taxi time 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. Alternatively, you may change the status to SWM (SIP Slot Improvement Proposal) Wanted Message), which gives an option of accepting or rejecting any improvement offered.

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

As soon as possible send a DLA/CHG stating your new EOBT (Estimated Off Block Time) or send an SMM, if your new EOBT is not known, to ensure that the slot can be reused and to minimise your risk of substantial delay.

Slot - What action do I take if I receive an SRM (Slot Revision Message)?

Comply with the new CTOT (Calculated Take-Off Time) stated in the message.

Slot - What do I do if I get an SLC (Slot Requirement Cancellation Message)?

You are no longer subject to ATFCM measures and may depart without delay. If the SLC is issued after EOBT (Estimated Off Block Time) +15 minutes you must update your EOBT by sending a DLA/CHG.

Slot - What do I do if I have missed my slot?

If your new EOBT (Estimated Off Block Time) is known send DLA/CHG. You will receive either: SRM (Slot Revision Message) , SLC (Slot Requirement Cancellation Message) or FLS (Flight Suspension Message)

If your new EOBT is not known send an SMM. You will receive an FLS (Flight Suspension message) and will remain suspended until you send a DLA to provide your new EOBT.

Slot - What happens if I update my EOBT (Estimated Off Block Time) after I have received a slot?

Normally, if the new EOBT still enables the flight to depart according to its CTOT (Calculated Take-Off Time), the slot will not be recalculated.
If a recalculation is necessary, the next available slot will be issued. To avoid a substantial delay, especially in busy regulations, it is therefore important to update EOBT as soon as practicable.

Slot - What happens if my slot changes?

You will receive an SRM (Slot Revision Message) with a new CTOT (Calculated Take-Off Time).

Slot - What kind of scenarios you could encounter in the event of a slot violation?

Air traffic flow management (ATFM) slot adherence monitoring is required by Commission Implementing Regulation (EU) No 255/2010.

Under Article 11 of this regulation, air traffic service (ATS) units are required to provide information regarding non-adherence to slots for these airports where slots are not adhered to for 20% or more of regulated departures, and also their action plans to mitigate such non-compliance.

Pursuant to Commission Implementing Regulation (EU) No 255/2010, the Network Manager (NM) monitors ATFM slot adherence on a monthly basis.

Commission Implementing Regulation (EU) No 390/2013 (Annex I, Section 2, paragraph 3.2(a)) also requires ATFM slot adherence to be monitored at local level, i.e. at national level with a breakdown at airport level.

Legal acts and agreements are stipulated in  Commission Implementing Regulation (EU) No 390/2013.

ATFM slot adherence is classified by Member State, with a breakdown for each airport subject to  Commission Implementing Regulation (EU) No 390/2013.

NM has monitored slot adherence to ATFM since 2011 and a report on ATFM slot adherence is released monthly with yearly aggregates. For more information on performance reporting, contact nm.ops.perf@eurocontrol.int.

Related links

Slot - What should I do if I need to make a last minute revision to CTOT (Calculated Take-Off Time)?

Revisions to CTOTs should, where possible, be coordinated between the AO and the NM using the ATFCM message exchange procedures. However, it may be the case that last minute revisions to CTOTs and slot extensions when the pilot is in direct communication with ATC, are more easily or efficiently coordinated with the FMP/NM by ATC

Slot - When do I get a slot CTOT (Calculated Take-Off Time)?

At the earliest, 2 hours before EOBT (Estimated Off Block Time) you will receive a SAM (Slot Allocation Message) with a CTOT. However, if a regulation is applied after this time a slot will be issued immediately.

Slot - Why did I receive an SRM (Slot Revision Message)?

There are several reasons why an SRM would be sent such as :

  • A better slot has been found for you.
  • In response to a rate change in a regulation.
  • In response to a DLA/CHG message, etc

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