The efficient utilisation of limited capacities at European airports requires careful planning and coordination of flight movements. For flights under instrument flight rules (IFR), the allocation of slots is essential. This article provides pilots with a comprehensive overview of the slot allocation process for IFR flights, including the legal framework, institutions involved and practical advice on how to apply for slots.
Legal basis for slot allocation
Slot allocation in Europe is based on Council Regulation (EEC) No 95/93 of 18 January 1993 on common rules for the allocation of slots at Community airports. This regulation lays down the criteria for the allocation and utilisation of slots and aims to ensure the efficient use of airport capacity.
Valid only for Germany (expand)
At national level, Flughafenkoordination Deutschland GmbH (Fluko) is tasked with airport coordination in accordance with Section 27a (1) of the German Air Traffic Act (LuftVG) by the Ordinance on the Assignment of Airport Coordinators (FHKBeauftrV). Fluko acts as a neutral coordinator and is responsible for the allocation of slots at the coordinated airports in Germany.
Valid only for Austria (expand)
In Austria, Schedule Coordination Austria (SCA) is responsible for the allocation of slots. The legal basis for this is the "Slot Coordination Ordinance" 155/2008 of the Republic of Austria. The SCA ensures that the available airport resources are optimally utilised.
Valid for Switzerland only (expand)
In Switzerland, slot coordination is organised by Slot Coordination Switzerland. This organisation is responsible for the allocation of slots at Zurich and Geneva airports and is financed by slot service fees, which are paid by the airports and users.
Classification of airports
Airports are divided into different categories according to their capacity utilisation and traffic volume:
Level 1 (Not coordinated)
Airports with sufficient capacity where no slot coordination is required.
Level 2 (flight plan mediated)
Airports with potential capacity bottlenecks at certain times. Here, flight plan switching is required to optimise the flow of traffic. In concrete terms, this means that a flight plan simply has to be submitted as for every IFR flight and the slot is then automatically requested and allocated when the flight plan is submitted. This means that no additional coordination is necessary.
Level 3 (Coordinated)
Airports with high capacity utilisation where slot coordination is essential.
The prior allocation of a slot is mandatory for IFR flights at Level 3 airports.
Valid only for Germany (expand)
Level 2 airports in Germany include
| Level 2 Airports | IATA / ICAO |
| Bremen Airport | BRE / EDDW |
| Dresden Airport | DRS / EDDC |
| Erfurt Airport | ERF / EDDE |
| Memmingen Airport | FMM / EDJA |
| Münster-Osnabrück Airport | FMO / EDDG |
| Leipzig-Halle Airport | LEJ / EDDP |
| Nuremberg Airport | NUE / EDDN |
| Saarbrücken Airport | SCN / EDDR |
In Germany, the following airports are Level 3 airports.
| Level 3 Airports | IATA / ICAO |
| Berlin Brandenburg Airport | BER / EDDB |
| Cologne-Bonn Airport | CGN / EDDK |
| Düsseldorf Airport | DUS / EDDL |
| Frankfurt Rhine-Main Airport | FRA / EDDF |
| Hanover Airport | HAJ / EDDV |
| Hamburg Airport | HAM / EDDH |
| Munich Airport | MUC / EDDM |
| Stuttgart Airport | STR / EDDS |
Valid only for Austria (expand)
In Austria, Vienna Airport (LOWW) and Innsbruck Airport (LOWI) are coordinated during the winter season on weekends and on 2 and 9 January (Level 3). A slot application is required for IFR flights at these times.
Valid for Switzerland only (expand)
In Switzerland, Zurich Airport (LSZH) requires prior slot allocation for IFR flights. Pilots receive the airport slot via their dispatcher or handling provider, and the slot ID must be entered in field 18 of the flight plan.
Applying for slots for IFR flights
Valid only for Germany (expand)
Role of Flughafenkoordination Deutschland GmbH (Fluko)
Fluko is the central institution for slot coordination in Germany. As a neutral coordinator, it is responsible for the allocation of slots at the coordinated airports. The tasks of Fluko include
- Slot allocation: Allocation of slots based on available capacity and airline requests.
- Flight schedule brokerage: Ensuring an efficient flow of traffic by coordinating flight schedules.
- Slot monitoring: Monitoring the utilisation of allocated slots and ensuring that slot times are adhered to.
Fluko acts independently and neutrally to ensure a fair and transparent slot allocation process.
Pilots and airlines wishing to operate IFR flights at coordinated airports in Germany must apply for a slot in advance. The process is as follows:
- Enquiry: Slot requests are made using the General Aviation Clearance Request (GCR) format. This standardised format enables efficient processing of requests.
- Transmission: The completed GCR message will be sent to Fluko by e-mail. For general aviation, the e-mail address fraztxh@fluko.org is available or alternatively by telephone: +49 69 257 585 - 120 (https://fluko.org/koordination/allgemeine-business-luftfahrt/)
- Confirmation: After the request has been checked, the applicant will receive a confirmation with the allocated slot times. These must then be entered in the flight plan
It is important that requests are made well in advance, especially during peak times or special events, as capacities are limited.
Structure of the GCR format
The GCR format consists of three main components:
- Format header: Contains the type of message (GCR) and the reference line for the corresponding aircraft identifier (/FLT for flight number or /REG for registration).
- Flight information line(s): Contains all necessary flight plan information, such as coordination code, aircraft identification or flight number, flight date, scheduled departure or arrival time, departure or destination airport, number of seats and aircraft type.
- Footnote: Optionally, additional information can be entered here, such as special instructions or general information.
Examples
1. new application for a slot
Scenario:
A Cessna 172 wants to take off from Frankfurt/Main Airport (EDDF) to Munich (EDDM) on 15 December at 10:00 UTC.
Format:
GCR
/REG
EDDF
N D-EABC 15DEC 004C172 1000EDDM D
GI BRGDS PILOT NAME
Explanation:
- N: Stands for "new application" for a slot.
- D-EABC: Aircraft identification.
- 15DEC: Date of the flight.
- 004C172: Capacity and aircraft type (Cessna 172 has room for 4 people, hence 004).
- 1000EDDM: Planned departure time (UTC) and destination airport.
- D: Flight type (Departure).
- GI: Final greetings and optional addition such as the pilot's name.
2. modification of an existing slot
Scenario:
The previously requested slot is to be changed to a new departure time at 11:30 UTC.
Format:
GCR
/REG
EDDF
C D-EABC 15DEC 004C172 1130EDDM D
GI BRGDS PILOT NAME
Explanation:
- C: Stands for "Change" (change of a slot).
- The rest of the format remains similar, but the new departure time (1130) is given.
3. cancellation of a slot
Scenario:
The previously requested slot for the flight from Frankfurt to Munich is to be cancelled.
Format:
GCR
/REG
EDDF
X D-EABC 15DEC 004C172 1000EDDM D
GI BRGDS PILOT NAME
Explanation:
- X: Stands for "Cancel" (cancellation of a slot).
- All other details such as licence plate number, flight date and time remain the same in order to clearly identify the specific slot.
Details on the format can be found here: GCR_GER
Valid only for Austria (expand)
Slot requests for Vienna Airport and Innsbruck Airport should be addressed to the General Aviation Operations Office of the respective airport. Requests can be made at the earliest 28 days before the planned flight.
Details on the slot enquiry can be found here: Slot enquiry Austria
Valid for Switzerland only (expand)
At Zurich Airport, slot bookings are made via the dispatcher or handling provider. The slot ID received must be stated in the flight plan.
Practical tips for pilots
- Early planning: Slot requests should be submitted early, especially during peak times, in order to have the best chance of being allocated a slot within the desired time slot.
- Flexibility: If the preferred slot is not available, alternative times can be suggested. Flexibility in planning can increase the likelihood of obtaining a suitable slot.
- Compliance with the slot times: Allocated slot times are binding. Pilots should ensure that they are at the take-off point on time to avoid delays and possible penalties.
- Communication: In the event of unexpected changes, such as technical problems or weather-related delays, the relevant coordination centre should be informed immediately. In such cases, new slots can be requested.
Support from software solutions such as autorouter.aero
In addition to the traditional method of creating slot requests manually and sending them to the coordination centre by email, pilots also have access to modern software solutions that can simplify and automate the entire process. One particularly widespread solution is autorouter.aero.
What is autorouter.aero?
Autorouter.aero is a platform developed specifically for the needs of IFR pilots. The software offers a wide range of functions, including
- Automated slot requests: The platform handles the creation and transmission of slot requests (e.g. for Germany in GCR format). Pilots simply have to enter their flight details and the software automatically generates the request in the correct format.
- Flight planning: Autorouter makes it easy to create and optimise IFR flight plans and provides access to validated flight routes. These routes are checked for validity in real time and can be submitted directly to the relevant authorities.
- Slot integration: As soon as a slot is assigned by the coordination centre, it is automatically integrated into the flight plan. This eliminates the need to manually synchronise slot times and flight schedules, which speeds up the process considerably.
- Notifications: The software informs pilots in real time about changes to allocated slots, such as delays or adjustments, and offers the option of requesting alternative slots directly.
Advantages of autorouter.aero and similar platforms
- Time saving: The automated creation and transmission of slot requests saves a considerable amount of time compared to manual processing.
- Error avoidance: Automation ensures that all relevant data is transmitted correctly and completely. This reduces the risk of delays due to formal errors.
- Simple operation: The user-friendly interface enables even less experienced users to efficiently organise the entire slot request and flight planning process.
- Integration with other systems: Autorouter can be integrated into many electronic flight planning tools, allowing pilots to seamlessly handle everything from slot requests to flight preparation in one platform.
- Mobility: As autorouter.aero is web-based, pilots can manage their slot requests and flight plans from any internet-enabled device.
How does it work in practice?
- Registration: Pilots register on the platform and enter basic data about their aircraft, such as aircraft type, registration and preferred airports.
- Flight planning: After entering the flight route and schedule, the software automatically creates the necessary slot requests.
- Transmission: The platform sends the slot request directly to the coordination centres as far as possible.
- Confirmation: As soon as a slot is assigned, the pilot receives a notification. This slot is integrated directly into the flight plan.
- Update: If the coordination centre makes changes, the software automatically adjusts the flight plan and informs the pilot.
Autorouter is ideal for private IFR pilots who regularly operate in a coordinated manner and do not want to deal with the details of the GCR format for Germany, for example.
Conclusion
Slot allocation for IFR flights at airports is a complex but well-structured process that is based on clearly defined legal principles. Pilots and airlines can ensure that they optimise the use of available resources through early planning and close communication with Fluko. With the upcoming developments in digitalisation and sustainability, slot allocation will remain a key issue for aviation in the future.