ENR 1.12 INTERCEPTION OF CIVIL AIRCRAFT

1 Notification

1.1 The procedure to be followed by the pilot-in-command of an intercepted aircraft and visual signals for use by intercepting and intercepted aircraft listed below are hereby notified for the purposes of the UK Air Navigation Order.

1.2 Under Article 9 of the Convention on International Civil Aviation, each contracting State reserves the right for reasons of military necessity or public safety, to restrict or prohibit the aircraft of other States from flying over certain areas of its territory.

1.3 The Regulations of a State may prescribe the need to investigate the identity of aircraft. Accordingly, it may be necessary to lead an aircraft of another nation, which has been intercepted, away from a particular area (such as a prohibited area) or, an intercepted aircraft may be required to land for security reasons at a designated aerodrome.

1.4 To avoid the interception of civil aircraft, adherence to flight plans and ATC procedures and the maintenance of a listening watch on the appropriate ATC frequency, make the possibility of interception highly improbable. If the identity of an aircraft is in doubt, all possible efforts will be made to secure identification through the appropriate Air Traffic Service Units.

1.5 As interception of civil aircraft are, in all cases, potentially hazardous, the interception procedures will only be used as a last resort.

1.6 The word 'interception' does not include the intercept and escort service provided on request to an aircraft in distress in accordance with Search and Rescue procedures.

1.7 An aircraft which is intercepted by another aircraft shall immediately:

Follow the instructions given by the intercepting aircraft, interpreting and responding to visual signals in accordance with the tables at ENR 1-12-2;
notify, if possible, the appropriate Air Traffic Services Unit;
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 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;
if equipped with SSR transponder, select Mode A, Code 7700 and Mode C, unless otherwise instructed by the appropriate Air Traffic Services Unit.

1.8 If radio contact with the intercepting aircraft is established but communication in a common language is not possible, attempts shall be made to convey essential information and acknowledgement of instructions by using the following phrases and pronunciations:

Phrase	Pronunciation	Meaning	Phrase	Pronunciation	Meaning
Callsign	Kol sa - In	My callsign is (callsign)	Mayday	Mayday	I am in distress
Wilco	Vill - Ko	Understood will comply	Hijack	Hi - Jack	I have been hijacked
Can Not	Kann Nott	Unable to comply	Land (place name)	Laand (place name)	I request to land at (place name)
Repeat	Ree - Peet	Repeat your instruction	Descend	Dee - Send	I require descent
Am Lost	Am Losst	Position unknown

Note 1: The callsign required to be given is that used in radiotelephony communications with Air Traffic Services Units and corresponding to the aircraft identification in the flight plan.

Note 2: Circumstances may not always permit, nor make desirable, the use of the phrase 'HIJACK'.

1.9 The following phrases are expected to be used by the intercepting aircraft in the circumstances described above: (SERA.11015 Interception Table S11-3 refers).

Phrase	Pronunciation	Meaning	Phrase	Pronunciation	Meaning
Callsign	Kol sa - In	What is your callsign?	You Land	You Laand	Land at this aerodrome
Follow	Fol - Lo	Follow me	Proceed	Pro - Seed	You may proceed
Descend	Dee - Send	Descend for landing

1.10 If any instructions received by radio from any sources conflict with those given by the intercepting aircraft by signals, the intercepted aircraft shall request immediate clarification while continuing to comply with the visual instructions given by the intercepting aircraft.

1.11 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.

2 SIGNALS FOR USE IN THE EVENT OF INTERCEPTION

Signals initiated by intercepting aircraft and responses by intercepted aircraft
Series	INTERCEPTING Aircraft Signals	Meaning	INTERCEPTED Aircraft Responds	Meaning
1	DAY-Rocking wings from a position slightly above and ahead of, and normally to the left of, the intercepted aircraft and, after acknowledgement, a slow level turn, normally to the left, on to the desired heading. NIGHT-Same and, in addition, flashing navigational lights at irregular intervals. Note 1: Meteorological conditions or terrain may require the intercepting aircraft to take up a position slightly above and ahead of, and to the right of the intercepted aircraft and to make the subsequent turn to the right. 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 race-track patterns and to rock its wings each time it passes the intercepted aircraft.	You have been intercepted. Follow me.	AEROPLANES: DAY-Rocking wings and following. NIGHT-Same and, in addition, flashing navigational lights at irregular intervals. HELICOPTERS: DAY or NIGHT-Rocking aircraft, flashing navigational lights at irregular intervals and following. Note: Additional action required to be taken by intercepted aircraft is prescribed in paragraphs 1.7, 1.8, 1.9, 1.10 and 1.11 on ENR 1-12-1.	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.	AEROPLANES: DAY or NIGHT- Rocking wings. HELICOPTERS: DAY or NIGHT-Rocking aircraft.	Understood, will comply.
3	DAY-Circling aerodrome, lowering landing gear and overflying runway in the direction of landing or, if the intercepted aircraft is a helicopter, overflying the helicopter landing area. NIGHT-Same and, in addition, showing steady landing lights.	Land at this aerodrome.	AEROPLANES: DAY-Lowering landing gear, following the intercepting aircraft and, if after over-flying the runway landing is considered safe, proceeding to land. NIGHT-Same and, in addition, showing steady landing lights (if carried). HELICOPTERS: DAY or NIGHT-Following the intercepting aircraft and proceeding to land, showing a steady landing light (if carried).	Understood, will comply.

Signals initiated by intercepted aircraft and responses by intercepting aircraft
Series	INTERCEPTED Aircraft Signals	Meaning	INTERCEPTING Aircraft Responds	Meaning
4	AEROPLANES: DAY-Raising landing gear while passing over landing runway at a height exceeding 300 m (1000 ft) but not exceeding 600 m (2000 ft) above the aerodrome level, and continuing to circle the aerodrome. NIGHT-Flashing landing lights while passing over landing runway at a height exceeding 300 m (1000 ft) but not exceeding 600 m (2000 ft) above the aerodrome level, and continuing to circle the aerodrome. 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 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	AEROPLANES: DAY or NIGHT- Regular switching on and off 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	AEROPLANES: DAY or NIGHT-Irregular flashing of all available lights. HELICOPTERS: DAY or NIGHT-Irregular flashing of all available lights.	In distress.	DAY or NIGHT-Use Series 2 signals prescribed for intercepting aircraft.	Understood.