ATS.TR.235 ATC clearances

The issuance of ATC clearances by air traffic control units constitutes authority for an aircraft to proceed only in so far as known air traffic is concerned. ATC clearances do not constitute authority to violate any applicable regulations for promoting the safety of flight operations or for any other purpose; neither do clearances relieve a pilot-in-command of any responsibility whatsoever in connection with a possible violation of applicable rules and regulations.

ASSURANCE OF OBSTACLE CLEARANCE IN VECTORING

(a)Prescribed obstacle clearance will exist at all times when an air traffic controller issues clearances at or above the established minimum flight altitudes.

(b)When an IFR flight is being vectored, the pilot may be unable to determine the aircraft’s exact position in respect of obstacles in this area and consequently the altitude which provides the required obstacle clearance.

CONTENTS OF CLEARANCES FOR DEPARTING AIRCRAFT Clearances for departing aircraft should specify, when necessary for the separation of aircraft:

(a)direction of take-off and turn after take-off;

(b)heading or track to be made good before taking up the cleared departure track;

(c)level to maintain before continuing climb to assigned level;

(d)time, point and/or rate at which a level change shall be made; and

(e)any other necessary manoeuvre consistent with safe operation of the aircraft.

CONTENTS OF STANDARD CLEARANCES FOR DEPARTING AIRCRAFT Standard clearances for departing aircraft should contain the following items:

(a)aircraft identification;

(b)clearance limit (normally destination aerodrome);

(c)designator of the assigned SID, if applicable;

(d)cleared level;

(e)allocated SSR code; and

(f)any other necessary instructions or information not contained in the SID description, e.g. instructions relating to change of frequency.

CLEARANCES FOR ARRIVING IFR FLIGHTS An IFR flight should neither be cleared for an initial approach below the appropriate minimum altitude as specified by the State concerned nor descend below that altitude unless:

(a)the pilot has reported passing an appropriate point defined by a navigation aid or as a waypoint; or

(b)the pilot reports that the aerodrome is and can be maintained in sight; or

(c)the aircraft is conducting a visual approach; or

(d)the air traffic controller has determined the aircraft’s position through the use of an ATS surveillance system, and a lower minimum altitude has been specified for use when providing ATS surveillance services.

CONTENTS OF STANDARD CLEARANCES FOR ARRIVING AIRCRAFT Standard clearances for arriving aircraft should contain the following items:

(a)aircraft identification;

(b)designator of the assigned STAR if applicable;

(c)runway-in-use, except when part of the STAR description;

(d)cleared level; and

(e)any other necessary instructions or information not contained in the STAR description, e.g. change of communications.

SPECIFICATION OF CLEARANCE LIMIT A clearance limit should be described by specifying the name of an appropriate significant point, or aerodrome, or controlled airspace boundary.

The phrase ‘cleared 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 (designation) departure’ or ‘cleared (designation) arrival’ may be used when standard departure or arrival routes have been established and published in AIPs.

INSTRUCTIONS IN CLEARANCES RELATING TO LEVELS Instructions included in clearances relating to levels should consist of:

(a)cruising level(s) or, for cruise climb, a range of levels, and, if necessary, the point to which the clearance is valid with regard to the level(s);

(b)levels at which specified significant points are to be crossed, when necessary;

(c)the place or time for starting climb or descent, when necessary;

(d)the rate of climb or descent, when necessary; and

(e)detailed instructions concerning departure or approach levels, when necessary.

ASSIGNMENT OF FLIGHT LEVELS FOR CONTROLLED FLIGHTS

(a)Except when traffic conditions and coordination procedures permit authorisation of cruise climb, an air traffic control unit should normally authorise only one level for an aircraft beyond its control area, i.e. that level at which the aircraft will enter the next control area whether contiguous or not. It is the responsibility of the accepting control unit to issue clearance for further climb as appropriate. When relevant, aircraft will be advised to request en-route any cruising level changes desired.

(b)In so far as practicable, cruising levels of aircraft flying to the same destination should be assigned in a manner that will be correct for an approach sequence at destination.

(c)An aircraft at a cruising level should normally have priority over other aircraft requesting that cruising level. When two or more aircraft are at the same cruising level, the preceding aircraft should normally have priority.

CONTENT OF THE CLEARANCES — TIME OF EXPIRY The time of expiry of the clearance indicates the time after which the clearance will be automatically cancelled if the flight has not been commenced.

ESTABLISHMENT AND PROCEDURES FOR STANDARD ARRIVAL AND DEPARTURE ROUTES Guidance related to the establishment of standard departure and arrival routes and associated procedures is available in ICAO Doc 9426 ‘ATS Planning Manual’ (Chapter 4, Appendix A).

CLEARANCES FOR TRANSONIC FLIGHT

(a)Air traffic control units should, whenever practicable, deliver clearance for the transonic acceleration phase to aircraft intending supersonic flight prior to departure.

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

CHANGE IN CLEARANCE REGARDING ROUTE The nature of the change should include a description of the route and levels to the point where it joins the previously cleared route, or, if the aircraft will not rejoin the previous route, to the destination.

CHANGE IN CLEARANCE REGARDING CRUISING LEVEL If it is necessary to change the cruising level of an aircraft operating along an established ATS route extending partly within and partly outside controlled airspace and where the respective series of cruising levels are not identical, the change should, whenever possible, be effected within controlled airspace.

READ-BACK OF CPDLC MESSAGES When so indicated by local safety assessments, the air traffic services provider may require that the receipt of some of the CPDLC message types (in particular those addressing trajectory changes) is acknowledged by voice.

CLEARANCE UPDATE Where a clearance is issued covering the initial part of the flight solely as a means of expediting departing traffic, the succeeding en-route clearance will be as specified in point (h)(1) of ATS.TR.235 even though the aerodrome of first intended landing is under the jurisdiction of an ACC other than the one issuing the en-route clearance.

AIR-GROUND COMMUNICATION FOR DELIVERY OF DOWNSTREAM CLEARANCES Where practicable, and where data link communications are used to facilitate downstream clearance delivery, two-way voice communications between the pilot and the air traffic control unit providing the downstream clearance should be available.