2.9 Air Traffic Control Clearances

GENERAL

2.9.1 ATC clearances are issued by ATSUs to aerodrome traffic and to IFR, VFR and SVFR flights operating within controlled airspace.

2.9.2 Clearances are based on known traffic conditions which affect safety of aircraft operations. Such traffic conditions include not only aircraft in the air and on the manoeuvring area over which control is being exercised.

2.9.3 ATC clearances constitute authority for an aircraft to proceed within the limits stated in the clearance but they do not relieve a pilot of any responsibility whatsoever in connection with a possible violation of applicable rules and regulations.

2.9.4 An ATC clearance may be issued in the form of an initial clearance or as an amendment to a previous clearance. An amendment shall automatically cancel any previous clearance issued.

CONTENTS OF AIR TRAFFIC CLEARANCES

2.9.5 An Air Traffic Control clearance shall include the following items:-

  1. aircraft identification;
  2. clearance limit;
  3. route;
  4. level of flight and changes of level.

2.9.6 The following items are to be added to a clearance as necessary:-

  1. ATCU identification;
  2. time restrictions;
  3. communications instructions;
  4. any special instructions e.g. rate of climb or descent, SIDs, STARs etc.

Note: Personnel relaying clearances to aircraft shall transmit such clearances in the exact phraseology in which they are received. (See Section 8 for phraseologies).

CLEARANCE LIMIT

2.9.7 A clearance limit is the point to which an aircraft is granted an Air Traffic Control clearance and shall be specified by naming:-

  1. an aerodrome;
  2. a reporting point;
  3. or a controlled airspace boundary.

2.9.8 An aircraft will be cleared to the aerodrome of first intended landing when:-

  1. it is planned to remain within controlled airspace throughout the flight; or
  2. an aircraft intends to leave controlled airspace, pass through uncontrolled airspace, and re-enter controlled airspace. Such clearance will only be valid for those portions of the flight which are conducted within controlled airspace.

2.9.9 In both of the above cases such clearance may only be issued when:-

  1. prior to departure the flight will be coordinated between all ATSU’s concerned; or
  2. there is reasonable assurance that prior co-ordination will be effected ahead of the aircraft’s passage.

2.9.10 To make the position quite clear to pilots, the following phrase must be added to all clearances for flights which will be leaving controlled airspace:-

“ZSABC, To leave controlled airspace at….(Control Area Boundary/Control Zone Boundary/position).”

ROUTES

2.9.11 Every endeavour shall be made to clear aircraft via the route or routes requested, where practicable.

CRUISING LEVELS

2.9.12 Normally, the cruising level requested in the flight plan is to be allocated, but if this level is not available, the nearest vacant level is to be allocated.

2.9.13 When two or more aircraft are at, or are requesting, the same cruising level, the preceding aircraft shall normally have priority.

PRIORITIES

2.9.14 Requests for clearances shall normally be dealt with in the order in which they are received and issued according to the traffic situation.

2.9.15 This order may be varied to facilitate the maximum number of flights with the least average delay. However, certain flights are given priority over others. The categorisation of these flights is given below.

    1. Aircraft in emergency (e.g. engine failure, fuel shortage, seriously ill person on board, ferry flights where one or more engines are inoperative).
    2. Ambulance aircraft.
  2. Normal flights (e.g. scheduled services, charter, executive, private, positioning and military flights).
  3. Special flights (e.g. survey flights, parachute dropping etc.).
  4. Training flights. These should be fitted into the normal traffic pattern as the opportunity occurs.

EN-ROUTE AIRCRAFT

2.9.16 Air Traffic Control clearances must be issued early enough to ensure that they are transmitted to the aircraft in sufficient time for it to comply with them.

2.9.17 Aircraft on flight plans specifying that the initial portion of the flight will be uncontrolled and that the subsequent portion of the flight will be subject to air traffic control by an ACC after the control area of origin, shall be advised to contact the ACC in whose area controlled flight will be commenced for clearance.

2.9.18 Aircraft on flight plans specifying that the first portion of the flight will be subject to air traffic control, and that the subsequent portion will be uncontrolled, shall normally be cleared to the point at which the controlled flight terminates.

2.9.19 An ACC may request an adjacent ACC to clear aircraft to a specified point during a specified period.

2.9.20 After the initial clearance has been issued to an aircraft at the point of departure, it will be the responsibility of the appropriate ACC to issue an amended clearance whenever necessary and to issue traffic information if required.

2.9.21 During the transonic and supersonic phases of a flight, amendments to the clearance should be kept to a minimum and must take due account of the operational limitations of the aircraft in these flight phases.

2.9.22 When so requested by the pilot, an aircraft shall be cleared for cruise climb whenever traffic conditions and co-ordination procedures permit. Such clearance shall be for cruise climb either above a specified level or between specified levels.

ROUTE OF FLIGHT

2.9.23 The route of flight shall be detailed in each clearance when deemed necessary. The phrase “cleared via flight planned route” may be used to describe any route or portion thereof provided the route or portion thereof is identical to that filed in the flight plan and sufficient routing details are given to definitely establish the aircraft on its route. The phrases “cleared via (designation) departure” or “cleared via (destination) arrival” may be used when standard departure or arrival routes have been established by the appropriate ATS authority and published in the AIP.