ENR 1.12  Interception of civil aircraft

1.   General

1.1  The interception procedures for civil aircraft conform to ICAO Annexes 2 and 11 and Doc 4444 (PANS-ATM).
1.2  Interception of civil aircraft will normally be limited to those instances where it is essential for the safe flight of the aircraft.
1.3  All possible efforts will be made to secure identification of an aircraft, which may be a civil aircraft, by means of effective coordination between the appropriate military units and the civil/military air traffic services units. Consequently there is no necessity for the establishment of designated areas or routes where special procedures are required in order to avoid the possible need for interception for the purpose of identification.
1.4  If, however, identification cannot be established by these means, interception procedures may be used as a last resort in accordance with the manoeuvres recommended in Annex 2, Attachment A, Section 3.
1.5  During interception manoeuvres, State aircraft take due account of performance limitations of civil aircraft, the need to avoid flying in such proximity to the intercepted aircraft that a collision hazard may be created and the need to avoid crossing the aircraft’s flight path in a manner that may create hazardous wake turbulence.
1.6  If it is considered necessary to intervene in the navigation of the intercepted aircraft, the intercepting aircraft will normally take up a position on the left (port) side slightly above and ahead of the intercepted aircraft, to enable the pilot-in-command of the latter aircraft to observe the visual signals given.
1.7  The visual signals for use in the event of interception will be those given in Section 4.

2.   Procedures for intercepted aircraft

Note: The word “interception” in this context does not include intercept and escort service provided, on request, to an aircraft in distress, in accordance with the Search and Rescue Manual (ICAO Doc 9731).

2.1  An aircraft which is intercepted by another aircraft shall immediately:
  1. follow the instructions given by the intercepting aircraft, interpreting and responding to visual signals in accordance with the specifications further in Annex 2, Appendix 1;
  2. notify, if possible, the appropriate air traffic services unit;
  3. attempt to establish radio communication with the intercepting aircraft or with the appropriate intercept control unit, by making a general call on the emergency frequency 121.500 MHz, giving the identity of the aircraft and the nature of the flight; and if no contact has been established and if practicable, repeating this call on the emergency frequency 243.000 MHz;
  4. if equipped with SSR transponder, select Mode A, Code 7700, unless otherwise instructed by the appropriate air traffic services unit.
2.2  If any instructions received by radio from any sources conflict with those given by the intercepting aircraft by visual signals, the intercepted aircraft shall request immediate clarification while continuing to comply with the visual instructions given by the intercepting aircraft.
2.3  If any instructions received by radio from any sources conflict with those given by the intercepting aircraft by radio, the intercepted aircraft shall request immediate clarification while continuing to comply with the radio instructions by the intercepting aircraft.

3.   Radio communication during interception

3.1  If radio contact is established during interception but communication in common language is not possible, attempts shall be made to convey instructions, acknowledgement of instructions and essential information by using the following phrases and pronunciations and transmitting each phrase twice.

a) Phrases for use by intercepting aircraft

PhrasePronunciation*Meaning
CALL SIGNKOL SA-INWhat is your call sign?
FOLLOWFOL-LOFollow me
DESCENTDEE-SENDDescent for landing
YOU LANDYOU LAANDLand at this aerodrome
PROCEEDPRO-SEEDYou may proceed

b) Phrases for use by intercepted aircraft

PhrasePronunciation*Meaning
CALL SIGN (call sign)*KOL SA-IN (call sign)My call sign is (call sign)
WILCOVILL-KOUnderstood. Will comply
CAN NOTKANN NOTTUnable to comply
REPEATREE-PEETRepeat your instruction
AM LOSTAM LOSSTPosition unknown
MAYDAYMAYDAYI am in distress
HIJACK*HI-JACKI have been hijacked
LAND (place name)LAAND (place name)I request to land at (place name)
DESCENTDEE-SENDI require descent

4.   Visual signals for use in the event of interception

4.1   Signals initiated by intercepting aircraft and responses by intercepted aircraft
SeriesINTERCEPTING aircraft signalsMeaningINTERCEPTED aircraft respondsMeaning
1.DAY or NIGHT - Rocking aircraft and flashing navigational lights at irregular intervals (and landing lights in the case of a helicopter) from a position slightly above and ahead of, and normally to the left of, the intercepted aircraft (or to the right if the intercepted aircraft is a helicopter) and, after acknowledgement, a slow level turn, normally to the left (or to the right in the case of a helicopter) on the desired heading.**You have been intercepted. Follow me.DAY or NIGHT - Rocking aircraft and flashing navigational lights at irregular intervals and following.*
Understood will comply
2.DAY or NIGHT - An abrupt break-away manoeuvre from the intercepted aircraft consisting of a climbing turn of 90 degrees or more without crossing the line of flight of the intercepted aircraftYou may proceed.DAY or NIGHT - Rocking the aircraft Understood will comply
3.DAY or NIGHT - Lowering landing gear (if fitted), showing steady landing lights and overflying the runway in use of, if the intercepted aircraft is a helicopter, overflying the helicopter landing area. In the case of helicopters, the intercepting helicopter makes a landing approach, coming to hover near to the landing area.Land at this aerodrome.DAY or NIGHT - Lowering landing gear (if fitted), showing steady landing lights and following the intercepting aircraft and, if, after overflying the runway in use or helicopter landing area, landing is considered safe, proceeding to land.Understood will comply
4.2   Signals initiated by intercepted aircraft and responses by intercepting aircraft
SeriesINTERCEPTED aircraft signalsMeaningINTERCEPTING aircraft respondsMeaning
4.DAY or NIGHT - Raising landing gear (if fitted) and flashing landing lights while passing over runway in use or helicopter landing area at a height exceeding 300 M (1 000 FT) but not exceeding 600 M (2 000 FT) (in the case of a helicopter, at a height exceeding 50 M (170 FT) but not exceeding 100 M (330 FT)) above the aerodrome level, and continuing to circle runway in use or helicopter landing area. If unable to flash landing lights, flash any other lights available.Aerodrome you have designated is inadequate.DAY or NIGHT - If it is desired that the intercepted aircraft follow the intercepting aircraft to an alternate aerodrome, the intercepting aircraft raises its landing gear (if fitted) and uses the Series 1 signals prescribed for intercepting aircraft.Understood follow me
If it is decided to release the intercepted aircraft, the intercepting aircraft uses the Series 2 signals prescribed for intercepting aircraft.Understood you may proceed.
5.DAY or NIGHT - Regular switching on and off of all available lights, but in such a manner as to be distinct from flashing lights.Cannot comply.DAY or NIGHT - Use Series 2 signals prescribed for intercepting aircraftUnderstood
6.DAY or NIGHT - Irregular flashing of all available lights.In distress.DAY or NIGHT - Use Series 2 signals prescribed for intercepting aircraftUnderstood