Contact

Post:	Aeronautical Information Management General Civil Aviation Authority P.O. Box 666 Abu Dhabi United Arab Emirates
Tel:	+971 2 599 6895
Fax:	+971 2 599 6889
AFS:	OMAEYOYX
Email:	aim@szc.gcaa.ae
URL:	www.gcaa.gov.ae

Aeronautical Information Circular - United Arab Emirates

General Civil Aviation Authority

AIC

A 01/2026

UFN

Published on 05 FEB 2026

DEPARTURE SLOT TIME PROCEDURE

INTRODUCTION

This Circular replaces AIC 04/2019, with the only change being the use of the term flight plan or FPL based on the context.

The departure slot allocation by EMIRATES ACC for the flights through the flow affected routes will be published through a web interface. The ATSUs and AOCs of UAE based airlines will be able to obtain DSTs as well as swap their DSTs using this web interface.

Non UAE based airlines shall obtain their DSTs from the ATSU of the departure aerodrome, inside 2 hours to EOBT. They are advised to file a flight plan at least 3 hours before EOBT.

Please refer to UAE NOTAM for the latest information.

ABBREVIATIONS

ACID	Aircraft Identification
ADEP	Departure Aerodrome
ADES	Destination Aerodrome
AOC	Airline Operation Centre
ATSU	Air Traffic Service Unit
ATYP	Type of Aircraft
CNS	Communication, Navigation and Surveillance
COBT	Calculated Off-Block Time
CTOT	Calculated Take-Off Time
DFLOW	Departure Flow Manager System
DST	Departure Slot Time
EOBT	Estimated Off-Block Time
ETOT	Estimated Take-Off Time
FPL	Filed flight plan exchanged via aeronautical fixed service (AFS)
FPOINT	Flow Point (Ex: LABRI, TARDI etc.)
Level#	Flight Level at Flow Point
OPR	Aircraft Operator
RWY	Planned Departure Runway
STATE	Slot State (Ex: “B”asic, “F”ixed)
Time#	Time at Flow Point
WTC	Wake Turbulence Category

DEFINITIONS

No.	Abbreviation	Definition
1	COBT	Calculated Off-Block Time - The calculated off-block time taking into account the CTOT minus TAXI OUT time.
2	CTOT	Calculated Take Off Time - A time calculated and issued by EMIRATES ACC, as a result of tactical slot allocation, at which a flight is expected to become airborne.
3	EOBT	Estimated Off-Block Time – The estimated time at which the aircraft will start movement associated with departure.
4	ETOT	Estimated Take Off Time - The estimated take off time taking into account the EOBT plus TAXI OUT time.
5	FPOINT	Flow Point - A point at which flow measures are imposed (Ex: LABRI, PURDA, TARDI etc.)
6	Level#(1,2,3)	The Flight Level that is available for the aircraft at the FPOINT taking into account the other traffic flying through the same FPOINT.
7	RWY	Planned Departure Runway.
8	STATE	State of the CTOT (Ex: “B”asic or “F”ixed) BASIC = In this state the CTOT will be adjusted for optimization. Swapping will be possible by airports or airlines. To reduce the overall delay, the system will continue the optimization of the CTOT until the current time is 2 hours to COBT. FIXED = In this state the system will not consider the CTOT for automatic optimization. Swapping of CTOTs will be possible by AOCs who has agreement with Control Tower or EMIRATES ACC. A CTOT will be fixed when the current time is inside 2 hours to COBT.
9	Time#(1,2,3)	The Time at which the aircraft is expected to reach the FPOINT taking into account the CTOT plus the flying time.

OBJECTIVE

The Web Interface of Departure Flow Manager system, DFLOW, is to enhance the departure slot allocation process by introducing transparent, efficient and automated measures. The core of the requirements and its implementation is as listed below:

No.	Requirements	Implementation
1	Availability of DSTs in advance	DSTs are available up to 6 hours before EOBT, subject to FPL availability
2	Transparency in allocation process	The entire DST allocations are displayed to all logged in users
3	Minimal role for Control Tower in DST allocations process	DST allocations are purely based on ATS Messages

BASIC PRINCIPLES

The following are the basic principles of DST Allocation Procedure:

Strictly follow the ATS messages transmission rules as prescribed in ICAO Doc 4444 – Appendix 2.
Flights through flow affected routes are advised to file a flight plan at least 3 hours before EOBT.
CTOTs will be issued 6 hours before COBT, subject to FPL availability.
From 6 hours to 2 hours before COBT, the CTOTs will be in “Basic” state as it may move up or down in the order for automatic optimization by the system.
Inside 2 hours of COBT, the DSTs will be in “Fixed” state as the system will not consider these slots for automatic optimization.
CTOT cancellation will be based on ATS CNL messages.
Swap of CTOTs is possible from the web based DFLOW.
AOCs will be able to swap CTOTs as per their time agreement with Aerodrome Control Tower.
Aerodrome Control Towers will be able to swap CTOTs up to departure time.
Airlines that are not based in the UAE shall obtain their CTOTs through the ATSU of departure aerodrome, inside 2 hours to EOBT.

DST ALLOCATION PROCEDURE

New CTOT:
1. Send a flight plan to the AFTN address OMAEZRZX at least 3 hours before EOBT.
2. Copy the CTOT (DST) from the DFLOW Web Interface which is automatically provided by the system for correctly received FPLs.
Note: Flight entry with DST will be visible after the next automatic refresh of the web browser, which is inside 60 seconds. Manual refresh can be performed by clicking on the refresh icon located in the bottom of the DST list.
Swapping CTOTs:
1. Single left click on 1st flight plan.
2. Ctrl + Single left click on 2nd flight plan.
3. Click on “Swap Slot” button.
4. Copy the CTOT (DST) from the DFLOW Web Interface.
Note 1: The swapping of flights are possible for logged in users under their jurisdiction.
Note 2 : The CTOTs are based on FPOINT and not on ADEP therefore swapping is possible for flights through the same FPOINT only.
Cancelling a CTOT:
- Send a CNL message to the AFTN address OMAEZRZX.
Note: Flight entry with DST will disappear after the next automatic refresh of the web browser, which is inside 60 seconds.
Delay message due to a late CTOT:
1. Once the system receives a DLA message for a flight then that flight will be allocated with a new CTOT.
2. Due to a high number of departures through an FPOINT, a flight may be issued with a CTOT causing a time difference of more than 30 minutes between EOBT and COBT. If a DLA message is sent to intimate this delay to the downstream FIRs, the time value of the DLA message shall be equal to the time in the COBT field of that flight. This will ensure that this flight is not subject to any further optimization. This is done as follows:
  - Copy the COBT of the flight from DFLOW Web Interface.
  - Send a DLA message to the AFTN address OMAEZRZX with the new time being exactly the same as displayed in the COBT.
Note : The status of the flight will be immediately changed to “Fixed” to avoid further optimization.

FALLBACK OPTIONS

In case the web based DFLOW is inaccessible, the CTOT can be obtained from EMIRATES ACC by calling on +971 2 558 2320. Swapping of CTOTs can also be requested from EMIRATES ACC through the same number.

For a new CTOT, send the FPL to OMAEZRZX and call the number above.
For swapping CTOTs, call the number above and provide the ACIDs to be swapped. Only one swap per call will be allowed.
For cancelling a CTOT, send the AFTN CNL message to OMAEZRZX.
Report the fault to EMIRATES ACC CNS Duty Engineer on +971 2 599 6864 or +971 50 615 2105

USERNAME ALLOCATION

To use DFLOW Web Interface, a username and password is required. These will be created by EMIRATES ACC.

To create a username, send the details to dataset@szc.gcaa.ae with the following information:

Preferred username.
Rights required:
1. Swapping - can swap flights, specify the duration before CTOT (ex: Until 2 hours before CTOT), or
2. No swapping - cannot swap flights.
Full name
Designation
Company
Email ID
Contact number

Note: The username creation is currently available to UAE based airlines and ATSUs only. Non UAE airlines will be notified for username creation in due course of time.