UK Aeronautical Information Services

NATS Swanwick, Room 3115

Sopwith Way,

Southampton, SO31 7AY

01489 887462

01912 032329 (Distribution)


AIC for United Kingdom

Aeronautical Information Service


Y 055/2018

Effective 07 JUN 2018


1 — Background

1.1 In order to provide a crossing or transit clearance of a Class D CTR or CTA, it is necessary for the ATC Unit responsible for the airspace to have the details of the proposed flight available.
1.2 This can be done by a pilot simply 'free' calling on the appropriate frequency and requesting the transit clearance.
1.3 The methodology meets with the requirements set out in the UK IAIP for providing 'the limited information required to obtain a clearance for a portion of a flight' (ENR 1.10, para 1.4), and is known as an Abbreviated Flight Plan.
1.4 An obvious drawback of this system is that the Air Traffic Controller responsible has no prior knowledge or warning of the request, and therefore has little opportunity to formulate a potential plan for the crossing. This is particularly important in today’s busy airspace where complex Air Traffic scenarios can develop rapidly.
1.5 Providing Abbreviated FPL information to ATC in advance would have several potential advantages:
  1. Enable early warning of requests;

  2. Enable better planning of transit flights through Class D airspace;

  3. Reduce the RTF loading when requests are made;

  4. Reduce ATC workload and therefore enable more efficient use of the airspace.

2 — Evaluation of a Pre-Notification Process for Class D CTA and CTR Transit Requests

2.1 In order to improve the timeliness of information available to ATC, an evaluation is to be conducted for flights that are intending to request a crossing clearance of the following Class D CTAs/CTRs in the London Area:
  1. Stansted CTA /CTR;

  2. Luton CTA/CTR;

  3. London (Heathrow) CTR (Outer);

  4. Gatwick CTA/CTR;

  5. London City CTA/CTR.

2.2 A simple online pre-notification tool (part of NATS Airspace User Portal) will be available which will allow pilots to 'file' in advance the limited details of an Abbreviated FPL required by ATC.
2.3 Access to the pre-notification tool will be via the NATS Airspace User Portal available at


2.4 A simple registration process allows pilots to access the pre-notification tool.
2.5  This evaluation will now continue until further notice. Enhancements to the Pre-Notification Tool will be made as the evaluation progresses.

3 — Procedure

3.1 A pilot of any flight that intends to request a crossing clearance for any of the above airspace is encouraged to 'file' an Abbreviated FPL on the day of the intended flight using the online pre-notification tool at least 60 minutes before the intended request time.
3.2 Access to the pre-notification tool can be found on the Airspace User Portal web page at:


3.3 The details required for each flight are limited to:
  1. Callsign;

  2. Aircraft Type;

  3. Point of Departure;

  4. Destination;

  5. Type of clearance required (IFR/VFR).

3.4 The CTA/CTR(s) through which clearance is being requested can be selected, and an approximate ETA (+/- 15 minutes) for each request should be entered.
3.5 Requests for transits of multiple regions for a single flight can be made.
3.6  Electronic submission of the information does not constitute any approval or clearance to cross or enter any Controlled Airspace.
3.7 After submission the Abbreviated FPL information will be provided to the Air Traffic Control Unit(s) responsible for the airspace selected by the pilot. An acknowledgement will also be sent to the users registered email address.
3.8 Once airborne, the pilot should make a request for transit of the airspace as normal, using the example phraseology:

'G-ABCD request transit, as filed'

3.9 ATC will acknowledge the transmission and consider the request. If possible, and depending on traffic, workload etc, an ATC clearance or alternative clearance will be then provided, which if acceptable to the pilot shall be read back in full.
3.10 The aircraft must remain outside any CAS until such time as ATC have provided a clearance and it has been acknowledged and read back by the pilot.
3.11  Whilst there remains no guarantee that a suitable ATC clearance can be provided on every occasion that a request is made, the pre-notification of Abbreviated Flight Plan details should enable some measure of pre-planning by ATC. Having flight details available in advance should also significantly reduce the amount of RTF required to facilitate such requests.
3.12 Should the flight subsequently not take place, or the transit clearance is no longer required, there is no requirement to cancel the online Abbreviated FPL. ATC will automatically discard the pre-notification if not used.

Note: The existing method of free calling the appropriate ATC Unit and requesting a clearance will remain available.

4 — Feedback and Further Information

4.1 Feedback on this evaluation is welcomed and should be submitted to:


Please do not use this address for the submission of any transit requests.