Understanding General Aviation Clearance Request (GCR) Airport Slots

PT 4 M minute read

There are several different airport slot request formats in use worldwide that impact business aircraft operations. By not being aware which format is applicable to your destination, you may face airport slot request rejections. Best practice is to always confirm the airport slot request format for your destination airports in advance and be aware that format and informational nuances may impact the slot request process.

One such format that is becoming more common is the General Aviation Clearance Request (GCR). Below are six tips to help you understand and navigate the GCR slot request process:

1. Meaning of GCR airport slots

GCRs are used at higher-traffic airports to obtain airport slots for arrival and departure. GCR differs in format from other airport slot request procedures, such as Slot Clearance Request (SCR) and Standard Schedules Information Manual (SSIM). Correct formatting is always a critical element in any airport slot request, as incorrectly formatted requests result in automatic rejection.

2. Where the GCR airport slot request format is used

Currently, there are about 20 major airports around the world using GCR format, including Hong Kong (VHHH), Dubai (OMDB), Frankfurt (EDDF), and several airports in Germany. OMDB was the most recent airport to move to GCR format, and this occurred about two years ago. Airports determine the airport slot request format that will be used at their location, as well as delivery and communication options. At some airports, preferred airport slot request procedure involves SITA and AFTN communication. More and more airports, however, are accepting and processing e-mail and online airport slot requests. This is making the process more user-friendly for operators.

3. How airport slot request formats differ

The difference between GCR and SCR formats is that GCR uses 4-letter ICAO airport identifiers, while SCR utilizes 3-letter IATA identifiers. SSIM format, used at locations including Israel and Portugal, varies from other formats in that operators must provide a reason for the flight, as well as the day of the week the aircraft will arrive. More agencies are leaning toward use of ICAO airport codes, such as in the GCR format, due to the fact that some 300 airports have the same IATA identifiers, which can cause confusion. Submitting an airport slot request in the wrong format, or with incorrect information, will result in rejection of your request. For this reason, it’s imperative to submit requests correctly. Airport slot coordinators usually respond quickly, within an hour during normal office hours, with confirmation or denial of airport slot requests. If a denial is issued, you’ll be provided with options, depending on what’s available. Once an airport slot is confirmed, it comes with a validity period prior to and after ETA/ETD.

4. Common airport slot request mistakes

Frequent errors include placing a departure request on the wrong line, missing coding, and spacing issues. Request errors seem to occur most often in airport slot revisions. Keep in mind that arrival and departure portions of the airport slot request are different. For example, when requesting airport slot revisions, always indicate both the previously approved slot and the new slot request. Keep in mind that there are nuances to consider when requesting slots, depending upon the airport. Many locations, including Frankfurt (EDDF), Nice (LFMN), Dubai (OMDB), Zurich (LSZH) and London-area airports during the 2012 London Olympics period, issue airport slot confirmation numbers that must be added to Remarks section 18 of the flight plan. Both Keflavik (BIKF) and OMDB require operators to provide a “call sign” in the airport slot request, even though the operator may not be using a call sign. In the case of OMDB, a flight number must be included in the slot request.

5. What happens if the requested slot is not available

If a requested slot is not available, you’ll be advised of options. It’s usually best to accept the closest airport slot offered, as these slot options may only be available for a limited time. In the case of revision requests, operators should consider retaining their original slot rather than accepting a new option that may be less favorable. The earliest you can request an airport slot for airports using the GCR format is 30 days prior to arrival or departure. Short-notice requests often result in limited options, and keep in mind that not all slot coordinators are available 24/7. Some airports provide instructions on how to request slots after hours. For instance, when operating to Germany after the slot office closes, you will be able to contact the Aeronautical Information Service (AIS) via an after-hours phone number. In the case of OMDB, after-hours airport slot requests are sub-contracted to the slot office at London-Heathrow (EGLL). For some locations, such as Geneva (LSGG), you can view available slots online 24/7 on the airport’s website.

6. Know before you go to avoid delays

Be aware that during special event periods or high season, you may not be able to get the airport slots you need. Some airports require both airport slots and prior permission required (PPR). You may receive a requested airport slot, but it will not be valid until PPR is approved separately. Typically, accepted airport slot deviation is -/+15 minutes. If you exceed permitted deviation, you may not be permitted to arrive/depart, and you may be even fined in some cases.


Provide plenty of advance notice when requesting airport slots and ensure that requests are formatted correctly to avoid processing delays or rejection. It’s recommended that passengers be advised of airport slot deviations for a particular airport in order to avoid potential mishaps and slot delays. If you’re running behind schedule and anticipating delay beyond your airport slot window, contact your 3rd-party provider or ground handler to notify airport authorities and revise slot times for you.


If you have any questions about this article or would like assistance planning your next trip to Israel, contact Christine Vamvakas at christinevamvakas@univ-wea.com.

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