Review Policy on Interception of Civil Aircraft

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Review Policy on Interception of Civil Aircraft

45TH ANNUAL CONFERENCE, Kaohsiung, Taiwan, 27-31 March 2006

WP No. 89

Review Policy on Interception of Civil Aircraft

Presented by PLC and TOC

Introduction

1.1.  Since the events of September 11th 2001, the number of civil aircraft being intercepted by military aircraft has increased.

1.2.  Member Associations (MAs) discovered a lack of the procedures and a shortcoming in regulations regarding interceptions.

1.3.  During the Melbourne Conference in 2005, Conference tasked TOC and PLC to review IFATCA policy on interceptions of civil aircraft.

1.4.  This paper will only address the procedures and regulations of the actual interception, the discussion that is ongoing about when to intercept civil aircraft is left out of this paper.

Discussion

2.1.  Interception of civil aircraft is not uncommon globally but since September 11th the amount and sort of interceptions have changed. Before September 11th most intercepts where done to identify unknown traffic or to escort VIP flights. After September 11th a lot of other reasons where given to justify interception, for example loss of communication, bomb threats, unexpected deviation of flight plan route, threats given via the media or directly to the crew, etc. The intercepts were not only carried out to escort or identify civil aircraft, but also to shoot them down in case they became a threat to national security.

2.2.  There is evidence showing that practise interceptions take place on civil aircraft, which IFATCA opposes and which is supported by ICAO Annex 2:

“1.1 To achieve the uniformity in regulations which is necessary for the safety of navigation of civil aircraft due regard shall be had by Contracting States to the following principles when developing regulations and administrative directives: […]

c) practice interception of civil aircraft will not be undertaken;”


2.3. Actual IFATCA Policy and ICAO procedures

2.3.1.  The IFATCA manual page 3242 states the following policy on interception of civil aircraft:

“To aid communication between intercepted and intercepting aircraft, and thereby lessen the possibility of drastic action being taken through misunderstanding or ignorance, IFATCA policy is:

A device should be developed which would permit two-way radio communication between intercepted and intercepting aircraft operating on VHF/UHF (at least 121.5 and 243.0 MHz) simultaneously.” (87/B.8/WP68)

 

Around the world there are still a lot of interceptors that are not VHF equipped, this creates a problem because they are not able to communicate directly with the intercepted aircraft. In these cases communication between the interceptor and the intercepted aircraft has to be relayed via another station or has to be done by using signals. Both ways are not favourable because they can lead to misinterpretation in a high tension situation. However, this problem mainly occurs with older airplanes, new generation interceptors are mostly equipped with both UHF and VHF radios. Taking into account the development costs to develop a system that can couple VHF and UHF in an aircraft as mentioned in the policy above it is not likely that many States will invest in such a system to equip older aircraft. Therefore it is better to urge States to equip their interceptors with VHF radios which are at least able to communicate on 121.5 MHz.

Since ICAO has a policy about this matter in Annex 2, Attachment A, Par. 2.3.f.;

“2.3 To eliminate or reduce the hazards inherent in interceptions undertaken as a last resort, all possible efforts should be made to ensure co-ordinated actions by the pilots and ground units concerned. To this end, it is essential that Contracting States take steps to ensure that:

f) intercept control units and intercepting aircraft be provided with radiotelephony equipment compatible with the technical specifications of Annex 10, Volume I so as to enable them to communicate with intercepted aircraft on the emergency frequency 121.5 MHz;”

the IFATCA policy is therefore recommended for deletion.

2.3.2.  Most intercepts will be done by a formation of interceptors and also when the interceptors are joined up with the intercepted aircraft we can speak of a formation flight. The IFATCA manual page 3274 states the following policy on formation flights within controlled airspace:

“By definition, formation flights occupy more airspace than individual flights and might therefore require greater than standard separation. Controllers need to be aware of the presence of a formation and therefore IFATCA policy is:

Additional separation, above that required by standard separation may be required in some cases between formation flights and other aircraft or other formation flights.

The word ‘formation’ shall be used in the radio callsign of a formation flight at least once, on first contact with each ATC frequency.” (91/B.3/WP91)

 

Due to the potential hazard involved with the interception, meaning the interception itself, the unknown flight path that can be followed by the intercepted aircraft and the unknown actions taken by the interceptor, it may be appropriate to take additional separation to that already taken for the formation flight.

2.3.3. The IFATCA manual page 4411 states the following policy on legal liability of the controller:

1.1.4: “IFATCA believes that it should be necessary to prove “mens rea” (guilty mind) beyond all reasonable doubt before a crime can exist. (Santiago 99.C.29)

1.1.5: “All other cases where “mens rea” cannot be proven must fall under Civil Law, as opposed to Criminal Law. It must be heard by a competent Civil Court and must be subject to the following conditions:” (Santiago 99.C.30)

1.1.5 g: “Military authorities and controllers to be subject to the same legislation when either they are controlling general air traffic, or an accident occurs involving general air traffic and operational air traffic, the latter being under military control or flying without control.”

 


2.4. ICAO annexes and Docs dealing with interceptions

2.4.1.  Annex 2 chapter 3; 3.8 – Interception (See Attachment 1):

“Interception of civil aircraft shall be governed by appropriate regulations and administrative directives issued by Contracting States in compliance with the Convention on International Civil Aviation…”

2.4.2.  Annex 2 Appendix 1, section 2; signals for use in the event of interception

In this Appendix all signals to be applied by the interceptor as well as the intercepted aircraft are detailed.

2.4.3.  Annex 2, Appendix 2; interception of civil aircraft (See Attachment 2)

Appendix 2 talks about principles to be followed when developing regulations and administrative directives, action to be taken by intercepted aircraft and radio communication during interception.

2.4.4.  Annex 2 Attachment A; interception of civil aircraft (See Attachment 3)

This Attachment contains:

“special recommendations which Contracting States are urged to implement through appropriate regulatory and administrative action, as interceptions of civil aircraft are, in all cases, potentially hazardous.”

2.4.5.  Annex 11 Par. 2.23.2.; interception of civil aircraft (See Attachment 4)

This paragraph contains the steps to be followed by an ATC unit when a civil aircraft is intercepted.

2.4.6.  ICAO Doc.9433

This ICAO Doc. is a summary of all the annexes and attachments that are dealing with interception of civil aircraft.

2.4.7.  PLC and TOC have reviewed the ICAO documentation and came to the conclusion that there is no need for more regulation and administrative directives to conduct a safe interception of civil aircraft. TOC and PLC urge all Member Associations (MAs) study their local procedures to ensure that clear and unambiguous procedures are in place.


2.5. Human Aspects

2.5.1. Controlling traffic that is intercepted by military aircraft could be a stressful situation for the ATCO. The ATC staff involved must have the opportunity to be relieved when the interception is completed. The impact on the staff involved can be extensive, particularly when the interception is terminated in the most extreme manner, and for this reason Critical Incident Stress Management (CISM) must be available for the staff that have dealt with the situation.


2.6. Liability

2.6.1.  It was discovered that in some countries the responsibility for providing separation between the interceptor and all other aircraft is not clearly defined.

2.6.2.  Since the ATCO has no control over the interceptor and in many cases, neither over the intercepted aircraft, he/she cannot be held liable for incidents and or accidents resulting from the interception.

Conclusions

3.1.  IFATCA policy on interception of civil aircraft:

“A device should be developed which would permit two-way radio communication between intercepted and intercepting aircraft operating on VHF/UHF (at least 121.5 and 243.0 MHz) simultaneously.”(87/B.8/WP68)

 

is no longer current. It is better to urge States to equip their interceptors with VHF radios which are at least able to communicate on the 121.5 MHz. ICAO has policy on this. Therefore IFATCA policy on interception of civil aircraft is recommended for deletion.

3.2.  Due to the potential hazard involved with the interception, meaning the interception itself, the unknown flight path that can be followed by the intercepted aircraft and the unknown actions taken by the interceptor, additional separation, above that required by standard separation is appropriate.

3.3.  There is sufficient ICAO documentation to enable a safe interception of civil aircraft to be conducted. All MAs are urged to study their local procedures to ensure that clear and unambiguous procedures are in place.

3.4.  Staff involved in an interception must have the possibility to be relieved when the interception has ended.

3.5.  CISM must be available for ATC staff involved in an interception.

3.6.  The responsibility for providing separation between the interceptor and all other aircraft must be clearly defined.

3.7.  ATCO’s should not be held liable for incidents or accidents resulting from an interception.

Recommendations

It is recommended that;

4.1.  IFATCA Policy on page 3 2 4 2 of the IFATCA Manual:

“A device should be developed which would permit two-way radio communication between intercepted and intercepting aircraft operating on VHF/UHF (at least 121.5 and 243.0 MHz) simultaneously.”

Is deleted.

4.2.  IFATCA Policy is:

“It is recommended to take additional separation, above that required by standard separation when separating from an interceptor or intercepted aircraft.”

And is included in the IFATCA Manual on page 3 2 4 2.

4.3.  IFATCA Policy is:

“CISM must be available for ATC staff involved in an interception.”

And is included in the IFATCA Manual on page 4 2 2 3, paragraph 2.4.5.

4.4.  IFATCA Policy is:

“The responsibility for providing separation between the intercepting aircraft and all other aircraft must be clearly defined.

ATCO’s should not be held liable for incidents or accidents resulting from an interception.”

And is included in the IFATCA Manual on page 4 4 1 5, new paragraph 1.2.24.

References

IFATCA Manual.

ICAO Annex 2.

ICAO Annex 11.

ICAO PANS ATM – Doc 4444.

ICAO Doc 9433.

Attachment 1 – Annex 2, Chapter 3

3.8 Interception

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 Volumes II and III of the International Aeronautical and Maritime Search and Rescue (IAMSAR) Manual (Doc 9731).

3.8.1 Interception of civil aircraft shall be governed by appropriate regulations and administrative directives issued by Contracting States in compliance with the Convention on International Civil Aviation, and in particular Article 3(d) under which Contracting States undertake, when issuing regulations for their State aircraft, to have due regard for the safety of navigation of civil aircraft. Accordingly, in drafting appropriate regulations and administrative directives due regard shall be had to the provisions of Appendix 1, Section 2 and Appendix 2, Section 1.

Note.— Recognizing that it is essential for the safety of flight that any visual signals employed in the event of an interception which should be undertaken only as a last resort be correctly employed and understood by civil and military aircraft throughout the world, the Council of the International Civil Aviation Organization, when adopting the visual signals in Appendix 1 to this Annex, urged Contracting States to ensure that they be strictly adhered to by their State aircraft. As interceptions of civil aircraft are, in all cases, potentially hazardous, the Council has also formulated special recommendations which Contracting States are urged to apply in a uniform manner. These special recommendations are contained in Attachment A.

3.8.2 The pilot-in-command of a civil aircraft, when intercepted, shall comply with the Standards in Appendix 2, Sections 2 and 3, interpreting and responding to visual signals as specified in Appendix 1, Section 2.

Attachment 2 – Annex 2, Appendix 2

APPENDIX 2. INTERCEPTION OF CIVIL AIRCRAFT

(Note.— See Chapter 3, 3.8 of the Annex)

1. Principles to be observed by States

1.1 To achieve the uniformity in regulations which is necessary for the safety of navigation of civil aircraft due regard shall be had by Contracting States to the following principles when developing regulations and administrative directives:

a) interception of civil aircraft will be undertaken only as a last resort;

b) if undertaken, an interception will be limited to determining the identity of the aircraft, unless it is necessary to return the aircraft to its planned track, direct it beyond the boundaries of national airspace, guide it away from a prohibited, restricted or danger area or instruct it to effect a landing at a designated aerodrome;

c) practice interception of civil aircraft will not be undertaken;

d) navigational guidance and related information will be given to an intercepted aircraft by radiotelephony, whenever radio contact can be established; and

e) in the case where an intercepted civil aircraft is required to land in the territory overflown, the aerodrome designated for the landing is to be suitable for the safe landing of the aircraft type concerned.

Note.— In the unanimous adoption by the 25th Session (Extraordinary) of the ICAO Assembly on 10 May 1984 of Article 3 bis to the Convention on International Civil Aviation, the Contracting States have recognized that “every State must refrain from resorting to the use of weapons against civil aircraft in flight.”

1.2 Contracting States shall publish a standard method that has been established for the manoeuvring of aircraft intercepting a civil aircraft. Such method shall be designed to avoid any hazard for the intercepted aircraft.

Note.— Special recommendations regarding a method for the manoeuvring are contained in Attachment A, Section 3.

1.3 Contracting States shall ensure that provision is made for the use of secondary surveillance radar, where available, to identify civil aircraft in areas where they may be subject to interception.

2. Action by intercepted aircraft

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

a) follow the instructions given by the intercepting aircraft, interpreting and responding to visual signals in accordance with the specifications in Appendix 1;

b) notify, if possible, the appropriate air traffic services unit;

c) 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;

d) 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 given by the intercepting aircraft.

3. Radiocommunication during interception

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 Table 2.1 and transmitting each phrase twice:

Table 2.1

1. In the second column, syllables to be emphasized are underlined.

2. The call sign 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.

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

Attachment 3 – Annex 2, Attachment A

ATTACHMENT A. INTERCEPTION OF CIVIL AIRCRAFT

(Note.— See Chapter 3, 3.8 of the Annex and associated Note)

Note.— In the interest of completeness, the substance of the provisions in Appendix 2 to the Annex is incorporated in this Attachment.)

1. In accordance with Article 3 d) of the Convention on International Civil Aviation the Contracting States of ICAO“ undertake, when issuing regulations for their state aircraft, that they will have due regard for the safety of navigation of civil aircraft”. As interceptions of civil aircraft are, in all cases, potentially hazardous, the Council of ICAO has formulated the following special recommendations which Contracting States are urged to implement through appropriate regulatory and administrative action. The uniform application by all concerned is considered essential in the interest of safety of civil aircraft and their occupants. For this reason the Council of ICAO invites Contracting States to notify ICAO of any differences which may exist between their national regulations or practices and the special recommendations hereunder.

2. General

2.1 Interception of civil aircraft should be avoided and should be undertaken only as a last resort. If undertaken, the interception should be limited to determining the identity of the aircraft, unless it is necessary to return the aircraft to its planned track, direct it beyond the boundaries of national airspace, guide it away from a prohibited, restricted or danger area or instruct it to effect a landing at a designated aerodrome. Practice interception of civil aircraft is not to be undertaken.

2.2 To eliminate or reduce the need for interception of civil aircraft, it is important that:

a) all possible efforts be made by intercept control units to secure identification of any aircraft which may be a civil aircraft, and to issue any necessary instructions or advice to such aircraft, through the appropriate air traffic services units. To this end, it is essential that means of rapid and reliable communications between intercept control units and air traffic services units be established and that agreements be formulated concerning exchanges of information between such units on the movements of civil aircraft, in accordance with the provisions of Annex 11;

b) areas prohibited to all civil flights and areas in which civil flight is not permitted without special authorization by the State be clearly promulgated in aeronautical information publications (AIP) in accordance with the provisions of Annex 15, together with the risk, if any, of interception in the event of penetration of such areas. When delineating such areas in close proximity to promulgated ATS routes, or other frequently used tracks, States should take into account the availability and over-all systems accuracy of the navigation systems to be used by civil aircraft and their ability to remain clear of the delineated areas;

c) the establishment of additional navigation aids be considered where necessary to ensure that civil aircraft are able safely to circumnavigate prohibited or, as required, restricted areas.

2.3 To eliminate or reduce the hazards inherent in interceptions undertaken as a last resort, all possible efforts should be made to ensure co-ordinated actions by the pilots and ground units concerned. To this end, it is essential that Contracting States take steps to ensure that:

a) all pilots of civil aircraft be made fully aware of the actions to be taken by them and the visual signals to be used, as specified in Chapter 3 and Appendix 1 of this Annex;

b) operators or pilots-in-command of civil aircraft implement the provisions in Annex 6, Parts I, II and III regarding the capability of aircraft to communicate on 121.5 MHz and the availability of interception procedures and visual signals on board aircraft;

c) all air traffic services personnel be made fully aware of the actions to be taken by them in accordance with the provisions of Annex 11, Chapter 2 and the PANS-ATM (Doc 4444);

d) all pilots-in-command of intercepting aircraft be made aware of the general performance limitations of civil aircraft and of the possibility that intercepted civil aircraft may be in a state of emergency due to technical difficulties or unlawful interference;

e) clear and unambiguous instructions be issued to intercept control units and to pilots-in- command of potential intercepting aircraft, covering interception manoeuvres, guidance of intercepted aircraft, action by intercepted aircraft, air-to-air visual signals, radio communication with intercepted aircraft, and the need to refrain from resorting to the use of weapons;

Note.— See paragraphs 3 to 8.

f) intercept control units and intercepting aircraft be provided with radiotelephony equipment compatible with the technical specifications of Annex 10, Volume I so as to enable them to communicate with intercepted aircraft on the emergency frequency 121.5 MHz;

g) secondary surveillance radar facilities be made available to the extent possible to permit intercept control units to identify civil aircraft in areas where they might otherwise be intercepted. Such facilities should permit recognition of discrete four-digit codes in Mode A, including immediate recognition of Mode A, Codes 7500, 7600 and 7700.

3. Interception manoeuvres

3.1 A standard method should be established for the manoeuvring of aircraft intercepting a civil aircraft in order to avoid any hazard for the intercepted aircraft. Such method should take due account of the 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 or to perform any other manoeuvre in such a manner that the wake turbulence may be hazardous, particularly if the intercepted aircraft is a light aircraft.

3.2 An aircraft equipped with an airborne collision avoidance system (ACAS), which is being intercepted, may perceive the interceptor as a collision threat and thus initiate an avoidance manoeuvre in response to an ACAS resolution advisory. Such a manoeuvre might be misinterpreted by the interceptor as an indication of unfriendly intentions. It is important, therefore, that pilots of intercepting aircraft equipped with a secondary surveillance radar (SSR) transponder, suppress the transmission of pressure-altitude information (in Mode C replies or in the AC field of Mode S replies) within a range of at least 37 km (20 NM) of the aircraft being intercepted. This prevents the ACAS in the intercepted aircraft from using resolution advisories in respect of the interceptor, while the ACAS traffic advisory information will remain available.

3.3 Manoeuvres for visual identification The following method is recommended for the manoeuvring of intercepting aircraft for the purpose of visually identifying a civil aircraft:

Phase I

The intercepting aircraft should approach the intercepted aircraft from astern. The element leader, or the single intercepting aircraft, should normally take up a position on the left (port) side, slightly above and ahead of the intercepted aircraft, within the field of view of the pilot of the intercepted aircraft, and initially not closer to the aircraft than 300 m. Any other participating aircraft should stay well clear of the intercepted aircraft, preferably above and behind. After speed and position have been established, the aircraft should, if necessary, proceed with Phase II of the procedure.

Phase II

The element leader, or the single intercepting aircraft, should begin closing in gently on the intercepted aircraft, at the same level, until no closer than absolutely necessary to obtain the information needed. The element leader, or the single intercepting aircraft, should use caution to avoid startling the flight crew or the passengers of the intercepted aircraft, keeping constantly in mind the fact that manoeuvres considered normal to an intercepting aircraft may be considered hazardous to passengers and crews of civil aircraft. Any other participating aircraft should continue to stay well clear of the intercepted aircraft. Upon completion of identification, the intercepting aircraft should withdraw from the vicinity of the intercepted aircraft as outlined in Phase III.

Phase III

The element leader, or the single intercepting aircraft, should break gently away from the intercepted aircraft in a shallow dive. Any other participating aircraft should stay well clear of the intercepted aircraft and rejoin their leader.

3.4 Manoeuvres for navigational guidance

3.4.1 If, following the identification manoeuvres in Phase I and Phase II above, it is considered necessary to intervene in the navigation of the intercepted aircraft, the element leader, or the single intercepting aircraft, should 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 see the visual signals given.

3.4.2 It is indispensable that the pilot-in-command of the intercepting aircraft be satisfied that the pilot-in-command of the intercepted aircraft is aware of the interception and acknowledges the signals given. If repeated attempts to attract the attention of the pilot-in-command of the intercepted aircraft by use of the Series 1 signal in Appendix 1, Section 2 are unsuccessful, other methods of signalling may be used for this purpose, including as a last resort the visual effect of the reheat/afterburner, provided that no hazard is created for the intercepted aircraft.

3.5 It is recognized that meteorological conditions or terrain may occasionally make it necessary for the element leader, or the single intercepting aircraft, to take up a position on the right (starboard) side, slightly above and ahead of the intercepted aircraft. In such case, the pilot-in- command of the intercepting aircraft must take particular care that the intercepting aircraft is clearly visible at all times to the pilot in command of the intercepted aircraft.

4. Guidance of an intercepted aircraft

4.1 Navigational guidance and related information should be given to an intercepted aircraft by radiotelephony, whenever radio contact can be established.

4.2 When navigational guidance is given to an intercepted aircraft, care must be taken that the aircraft is not led into conditions where the visibility may be reduced below that required to maintain flight in visual meteorological conditions and that the manoeuvres demanded of the intercepted aircraft do not add to already existing hazards in the event that the operating efficiency of the aircraft is impaired.

4.3 In the exceptional case where an intercepted civil aircraft is required to land in the territory over flown, care must also be taken that:

a) the designated aerodrome is suitable for the safe landing of the aircraft type concerned, especially if the aerodrome is not normally used for civil air transport operations;

b) the surrounding terrain is suitable for circling, approach and missed approach manoeuvres;

c) the intercepted aircraft has sufficient fuel remaining to reach the aerodrome;

d) if the intercepted aircraft is a civil transport aircraft, the designated aerodrome has a runway with a length equivalent to at least 2 500 m at mean sea level and a bearing strength sufficient to support the aircraft; and

e) whenever possible, the designated aerodrome is one that is described in detail in the relevant aeronautical information publication.

4.4 When requiring a civil aircraft to land at an unfamiliar aerodrome, it is essential that sufficient time be allowed it to prepare for a landing, bearing in mind that only the pilot-in command of the civil aircraft can judge the safety of the landing operation in relation to runway length and aircraft mass at the time.

4.5 It is particularly important that all information necessary to facilitate a safe approach and landing be given to the intercepted aircraft by radiotelephony.

5. Action by intercepted aircraft

The Standards in Appendix 2, Section 2 specify as follows:

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

a) follow the instructions given by the intercepting aircraft, interpreting and responding to visual signals in accordance with the specifications in Appendix 1;

b) notify, if possible, the appropriate air traffic services unit;

c) attempt to establish radiocommunication 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;

d) 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 given by the intercepting aircraft.

6. Air-to-air visual signals

The visual signals to be used by intercepting and intercepted aircraft are those set forth in Appendix 1 to this Annex. It is essential that intercepting and intercepted aircraft adhere strictly to those signals and interpret correctly the signals given by the other aircraft, and that the intercepting aircraft pay particular attention to any signals given by the intercepted aircraft to indicate that it is in a state of distress or urgency.

7. Radiocommunication between the intercept control unit or the intercepting aircraft and the intercepted aircraft

7.1 When an interception is being made, the intercept control unit and the intercepting aircraft should:

a) first attempt to establish two-way communication with the intercepted aircraft in a common language on the emergency frequency 121.5 MHz, using the call signs “INTERCEPT CONTROL”, “INTERCEPTOR (call sign)” and “INTERCEPTED AIRCRAFT” respectively; and

b) failing this, attempt to establish two-way communication with the intercepted aircraft on such other frequency or frequencies as may have been prescribed by the appropriate ATS authority, or to establish contact through the appropriate ATS unit(s).

7.2 If radio contact is established during interception but communication in a common language is not possible, attempts must be made to convey instructions, acknowledgement of instructions and essential information by using the phrases and pronunciations in Table A-1 and transmitting each phrase twice.

Table A.1

1. In the second column, syllables to be emphasized are underlined.

2. The call sign 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.
3. Circumstances may not always permit, nor make desirable, the use of the phrase “HIJACK”.

8. Refraining from the use of weapons

Note.— In the unanimous adoption by the 25th Session (Extraordinary) of the ICAO Assembly on 10 May 1984 of Article 3 bis to the Convention on International Civil Aviation, the Contracting States have recognized that “every State must refrain from resorting to the use of weapons against civil aircraft in flight.”

The use of tracer bullets to attract attention is hazardous, and it is expected that measures will be taken to avoid their use so that the lives of persons on board and the safety of aircraft will not be endangered.

9. Co-ordination between intercept control units and air traffic services units

It is essential that close co-ordination be maintained between an intercept control unit and the appropriate air traffic services unit during all phases of an interception of an aircraft which is, or might be, a civil aircraft, in order that the air traffic services unit is kept fully informed of the developments and of the action required of the intercepted aircraft.

Attachment 4 – Annex 11

2.23.2 Interception of civil aircraft

2.23.2.1 As soon as an air traffic services unit learns that an aircraft is being intercepted in its area of responsibility, it shall take such of the following steps as are appropriate in the circumstances:

a) attempt to establish two-way communication with the intercepted aircraft via any means available, including the emergency radio frequency 121.5 MHz, unless such communication already exists;

b) inform the pilot of the intercepted aircraft of the interception;

c) establish contact with the intercept control unit maintaining two-way communication with the intercepting aircraft and provide it with available information concerning the aircraft;

d) relay messages between the intercepting aircraft or the intercept control unit and the intercepted aircraft, as necessary;

e) in close coordination with the intercept control unit take all necessary steps to ensure the safety of the intercepted aircraft;

f) inform ATS units serving adjacent flight information regions if it appears that the aircraft has strayed from such adjacent flight information regions.

2.23.2.2 As soon as an air traffic services unit learns that an aircraft is being intercepted outside its area of responsibility, it shall take such of the following steps as are appropriate in the circumstances:

a) inform the ATS unit serving the airspace in which the interception is taking place, providing this unit with available information that will assist in identifying the aircraft and requesting it to take action in accordance with 2.23.2.1;

b) relay messages between the intercepted aircraft and the appropriate ATS unit, the intercept control unit or the intercepting aircraft.

Last Update: March 29, 2020  

March 29, 2020   60   Jean-Francois Lepage    2006    

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