ENR 1.12  Interception of Civil Aircraft

Occasions may arise when, after all other means have been exhausted, it is necessary for military reasons of public safety to intercept an aircraft to:

Adherence to the flight plan and ATC procedures and the maintenance of a listening watch on appropriate ATC frequencies will make the occurrence of an interception highly unlikely for civil aircraft. However, should the occasion arise, the rules laid down in SERA apply.

1   INTERCEPTION PROCEDURES (SERA.11015)

Note: The word “interception” in this context does not include intercept and escort service provided, on request, to an aircraft in distress.

The pilot in command of a civil aircraft, when intercepted, shall:

  1. immediately follow the instructions given by the intercepting aircraft, interpreting and responding to visual signals in accordance with the specifications in § 2 below;

  2. notify, if possible, the appropriate ATS 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 intercepted aircraft and the nature of the flight; 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 ATS unit;

  5. if equipped with ADS-B or ADS-C, select the appropriate emergency functionality, if available, unless otherwise instructed by the appropriate ATS unit.

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.

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.

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:

The phrases shown in the table below shall be used by the intercepting aircraft.

PhrasePronunciation (1)Meaning
CALL SIGNKOL SA-INWhat is your call sign?
FOLLOWFOL-LOFollow me
DESCENDDEE-SENDDescend for landing
YOU LANDYOU LAANDLand at this aerodrome
PROCEEDPRO-SEEDYou may proceed
(1) Syllables to be emphasised are underlined.

The phrases shown in the table below shall be used by the intercepted aircraft.

PhrasePronunciation (1)Meaning
CALL SIGN (call sign) (2)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 (3)HI-JACKI have been hijacked
LAND (place name)LAAND (place name)I request to land at (place name)
DESCENDDEE-SENDI require descent

(1) Syllables to be emphasised are underlined.

(2) The call sign required to be given is that used in RTF communications with ATS units and corresponding to the aircraft identification in the flight plan.

(3) Circumstances may not always permit, nor make desirable, the use of the phrase “HIJACK”.

2   SIGNALS FOR USE IN THE EVENT OF INTERCEPTION

Signals Initiated by Intercepting Aircraft and Responses by Intercepted Aircraft
SeriesINTERCEPTING Aircraft SignalsMeaningINTERCEPTED Aircraft RespondsMeaning
1DAY 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: MET conditions or terrain may require the intercepting aircraft to reverse the positions and direction of turn.

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 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.
2DAY 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 aircraft.You may proceed.DAY or NIGHT. Rocking the aircraft.Understood.will comply.
3DAY 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 or helicopter landing area, landing is considered safe, proceeding to land.Understood.will comply.
Signals Initiated by Intercepted Aircraft and Responses by Intercepting Aircraft
SeriesINTERCEPTED Aircraft Signals MeaningINTERCEPTING Aircraft Responds Meaning
4DAY 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 1 000  FT but not exceeding 2 000 FT (in the case of a helicopter, at a height exceeding 170 FT but not exceeding 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 follows 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.
5DAY 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 (see above).Understood.
6DAY or NIGHT. Irregular flashing of all available lights.In distress.DAY or NIGHT. Use series 2 signals prescribed for intercepting aircraft (see above).Understood.

3   MILITARY PROCEDURES

The intercept control unit (CRC Glons or CRC Nieuw Milligen) will advise Semmerzake ATCC of the position of the intercepted aircraft and the intercepting aircraft and of the estimated approach heading of the latter. Semmerzake ATCC will in its turn advise the civil agency controlling the intercepted aircraft.