ENR 1.12  INTERCEPTION OF CIVIL AIRCRAFT

1 General Rules
1.1 When an aircraft is being intercepted, the relevant ICAO provisions including signals and responses to be used shall be complied with. The pilot of the intercepted aircraft shall, whenever possible, notify the ATS unit concerned, who will offer assistance to the intercepted aircraft as far as possible.
2 Action for intercepted aircraft
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 in para. 4 below;
  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 121.5 MHZ, giving the identity of the intercepted 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 MHz;
  4. if equipped with SSR transponder, select Mode A, Code 7700, unless otherwise instructed by the appropriate air traffic services unit;
  5. if equipped with ADS-B or ADS-C, select the appropriate emergency functionality, if available, 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 signal, 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 given by the intercepting aircraft.
3 Radio communication during interception
3.1 If radio contact is established during interception but communication in a common language is not possible, attempts shall be made to convey instructions, acknowledgement of instructions and essential information by using the phrases and pronunciations in the following tables and transmitting each phrase twice:

a) Phrases for use by INTERCEPTING aircraft

Phrase Pronunciation 1 Meaning
CALL SIGN KOL-SA-IN What is your call sign?
FOLLOW FOL-LO Follow me
DESCEND DEE-SEND Descend for landing
YOU LAND YOU LAAND Land at this aerodrome
PROCEED PRO-SEED You may proceed 

b) Phrases for use by INTERCEPTED aircraft

Phrase Pronunciation 1 Meaning
CALL SIGN 2 KOL-SA-IN My call sign is (call sign)
WILCO VILL-KO Understood 
CAN NOT KANN NOTT Unable to comply
REPEAT REE-PEET Repeat your instruction
AM LOST AM LOSST Position unknown
MAYDAY MAYDAY I am in distress
HIJACK 3 HI-JACK I have been hijacked
LAND (place name) LAAND (place name) I request to land at (place name)
DESCEND DEE-SEND I require descent

4 Signals for use in the event of interception
4.1 Signals initiated by intercepting aircraft and responses by intercepted aircraft
Series INTERCEPTING Aircraft Signals Meaning INTERCEPTED Aircraft Responds Meaning
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.

Note 1. - Meteorological conditions or terrain may require the intercepting aircraft to reverse the positions and direction of turn given above in Series 1.

Note 2. - If the intercepted aircraft is not able to keep pace with the intercepting aircraft, the latter is expected to fly a series of racetrack patterns and to rock the aircraft each time it passes the intercepted aircraft.		 You have been intercepted. Follow me. DAY or NIGHT - Rocking aircraft, flashing navigational lights at irregular intervals and following. Understood, will comply. 
2 DAY or NIGHT - An abrupt breakaway manoeuvre from the intercepted aircraft consisting of a climbing turn of 90 degrees or more without crossing the line of flight of the intercepted aircraft. You 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 runway in use or, 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
Series INTERCEPTED Aircraft Signals Meaning INTERCEPTING Aircraft Responds Meaning
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.

If it is decided to release the intercepted aircraft, the intercepting aircraft uses the Series 2 signals prescribed for intercepting aircraft.		 Understood, follow me.







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 aircraft. Understood.
6 DAY or NIGHT - Irregular flashing of all available lights. In distress. DAY or NIGHT - Use Series 2 signals prescribed for intercepting aircraft. Understood.