Lost Communications


Eddie sez:

If you are a U.S. pilot who never leaves the confines of the United States and Canada, lost communications are pretty easy to remember and you should have no problem. See United States Exceptions for the specific procedures.

"Exceptions?" you say? Yes, what you grew up with are an exception to International Procedures and if you venture outside our shores, you have some studying to do.

If you have a copy of Jeppesen Airways Manual you should have all you need to learn about individual country lost communications procedures, but you need to understand International Standard Procedures first. Those are listed below, along with a few of the exceptions just to get you started. Remember that these are as of the date given at the bottom of the page. If you are leaving your home country tomorrow, you need to make sure your knowledge is up to date.

If you don't have a current Jeppesen Airways Manual I'm not sure where you can turn. Each country is required to post their differences from the ICAO standard in their individual Aeronautical Information Publication (AIP), but few of these are in English and fewer still are easily obtainable. ICAO Doc 7030 - Regional Supplementary Procedures was supposed to have fixed all this, but it did not. Be careful out there.

You almost never hear about airplanes these days going lost comm and having some kind of problem that ends up tragically. But it does happen. While it would be wrong to say the midair over Brazil by Embraer 135BJ N600XL and Gol Flight 1907 was caused by the American pilots using the wrong lost communications procedure, it is certainly true that the midair would not have happened had they applied ICAO procedures.

Last revision:


International Standard Procedures

These procedures are what most of the world use and you should either have them memorized or easily accessible anytime you fly outside your home country. For us brought up in the United States, the key points are these: (1) timing depends on whether or not you are in radar contact, and (2) your altitude depends on your filed flight plan.

[ICAO Annex 2, ¶3.6.5] An aircraft operated as a controlled flight shall maintain continuous air-ground voice communication watch on the appropriate communication channel of, and establish two-way communication as necessary with, the appropriate air traffic control unit, except as may be prescribed by the appropriate ATS authority in respect of aircraft forming part of aerodrome traffic at a controlled aerodrome.

Note 1.— SELCAL or similar automatic signalling devices satisfy the requirement to maintain an air-ground voice communication watch.

Note 2.— The requirement for an aircraft to maintain an air-ground voice communication watch remains in effect after CPDLC has been established. Communication failure. If a communication failure precludes compliance with, the aircraft shall comply with the voice communication failure procedures of Annex 10, Volume II, and with such of the following procedures as are appropriate. The aircraft shall attempt to establish communications with the appropriate air traffic control unit using all other available means. In addition, the aircraft, when forming part of the aerodrome traffic at a controlled aerodrome, shall keep a watch for such instructions as may be issued by visual signals.

Annex 10, Volume II is a large document but there are a few specific paragraphs about communications failure, shown below. If in visual meteorological conditions, the aircraft shall:

a) continue to fly in visual meteorological conditions; land at the nearest suitable aerodrome; and report its arrival by the most expeditious means to the appropriate air traffic services unit;

b) if considered advisable, complete an IFR flight in accordance with If in instrument meteorological conditions or when the pilot of an IFR flight considers it inadvisable to complete the flight in accordance with a), the aircraft shall:

a) unless otherwise prescribed on the basis of regional air navigation agreement, in airspace where radar is not used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 20 minutes following the aircraft's failure to report its position over a compulsory reporting point and thereafter adjust level and speed in accordance with the filed flight plan;

b) in airspace where radar is used in the provision of air traffic control, maintain the last assigned speed and level, or minimum flight altitude if higher, for a period of 7 minutes following:

1) the time the last assigned level or minimum flight altitude is reached; or

2) the time the transponder is set to Code 7600; or

3) the aircraft's failure to report its position over a compulsory reporting point;

whichever is later, and thereafter adjust level and speed in accordance with the filed flight plan;

c) when being radar vectored or having been directed by ATC to proceed offset using area navigation (RNAV) without a specified limit, rejoin the current flight plan route no later than the next significant point, taking into consideration the applicable minimum flight altitude;

d) proceed according to the current flight plan route to the appropriate designated navigation aid or fix serving the destination aerodrome and, when required to ensure compliance with e) below, hold over this aid or fix until commencement of descent;

e) commence descent from the navigation aid or fix specified in d) at, or as close as possible to, the expected approach time last received and acknowledged; or, if no expected approach time has been received and acknowledged, at, or as close as possible to, the estimated time of arrival resulting from the current flight plan;

f) complete a normal instrument approach procedure as specified for the designated navigation aid or fix; and

g) land, if possible, within 30 minutes after the estimated time of arrival specified in e) or the last acknowledged expected approach time, whichever is later.

Note 1.— The provision of air traffic control service to other flights operating in the airspace concerned will be based on the premise that an aircraft experiencing communication failure will comply with the rules in

Note 2. — See also 5.1.2.

[ICAO Annex 2, ¶5.1.2]

Except when necessary for take-off or landing, or except when specifically authorized by the appropriate authority, an IFR flight shall be flown at a level which is not below the minimum flight altitude established by the State whose territory is overflown, or, where no such minimum flight altitude has been established:

a) over high terrain or in mountainous areas, at a level which is at least 600 m (2 000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft;

b) elsewhere than as specified in a), at a level which is at least 300 m (1,000 ft) above the highest obstacle located within 8 km of the estimated position of the aircraft.

Note 1.— The estimated position of the aircraft will take account of the navigational accuracy which can be achieved on the relevant route segment, having regard to the navigational facilities available on the ground and in the aircraft.

Note 2.— See also 3.1.2.

[ICAO Annex 2, ¶3.1.2] Minimum heights

Except when necessary for take-off or landing, or except by permission from the appropriate authority, aircraft shall not be flown over the congested areas of cities, towns or settlements or over an open-air assembly of persons, unless at such a height as will permit, in the event of an emergency arising, a landing to be made without undue hazard to persons or property on the surface.

[ICAO Annex 10, ¶] Communications Failure Air-ground When an aircraft station fails to establish contact with the aeronautical station on the designated frequency, it shall attempt to establish contact on another frequency appropriate to the route. If this attempt fails, the aircraft station shall attempt to establish communication with other aircraft or other aeronautical stations on frequencies appropriate to the route. In addition, an aircraft operating within a network shall monitor the appropriate VHF frequency for calls from nearby aircraft. If the attempts specified under fail, the aircraft station shall transmit its message twice on the designated frequency(ies), preceded by the phrase "TRANSMITTING BLIND" and, if necessary, include the addressee(s) for which the message is intended. PANS.— In network operation, a message which is transmitted blind should be transmitted twice on both primary and secondary frequencies. Before changing frequency, the aircraft station should announce the frequency to which it is changing.

Canadian Exceptions

[Canadian Aviation Regulations, §602.137] Two-way Radiocommunication Failure in IFR Flight

(1) Where there is a two-way radiocommunication failure between the controlling air traffic control unit and an IFR aircraft that is in or has received a clearance to enter controlled airspace, the pilot-in-command shall

(a) maintain a listening watch on the appropriate frequency for control messages or further clearance and acknowledge receipt of any such messages, if possible, by any means available;

(b) set the transponder to code 7600; and

(c) attempt to establish communications with any air traffic services facility or other aircraft, inform the facility or aircraft of the difficulty and request it to relay the information to the last air traffic control unit with which communications had been established.

(2) Where communications cannot be established with any air traffic services facility, either directly or by relay through an intermediary, the pilot-in-command shall, except where specific instructions to cover an anticipated communications failure have been received from an air traffic control unit, comply with the procedures specified by the Minister in the Canada Air Pilot and the Canada Flight Supplement.

[Canadian Aviation Regulations, §602.138] Two-way Radiocommunication Failure in VFR Flight

Where there is a two-way radiocommunication failure between the controlling air traffic control unit and a VFR aircraft while operating in Class B, Class C or Class D airspace, the pilot-in-command shall

(a) leave the airspace

(i) where the airspace is a control zone, by landing at the aerodrome for which the control zone is established, and

(ii) in any other case, by the shortest route;

(b) where the aircraft is equipped with a transponder, set the transponder to code 7600; and

(c) inform an air traffic control unit as soon as possible of the actions taken pursuant to paragraph (a).

The references to "procedures specified by the Minister in the Canada Air Pilot and the Canada Flight Supplement" appear to refer to the "Rules of the Air" (RAC) section of the Transport Canada Aeronautical Information Manual, and closely mirror procedures in the United States. Canadian pilots flying in the United States are provided with this caution:

[Transport Canada Aeronautical Information Manual, §RAC, ¶6.3.2.]

  • For flights to the United States, communications failure procedures are essentially the same, but it is the pilot's responsibility to consult the appropriate American publications. Some instrument procedures do not include a procedure turn but include the statement "RADAR OR RNAV REQUIRED" as part of the procedure. The initial approach segment of these instrument procedures is being provided by ATC radar vectors. Without ATC radar vectoring, the instrument procedure may not have a published initial approach segment.
  • Should an aircraft communications failure occur while the aircraft is being vectored on one of these approaches, separately or as part of a STAR, the pilot is expected to comply with the communications failure procedure by selecting the transponder to Mode A/3 Code 7600 immediately. Pilots should always be aware of the traffic situation. For example, ATC may have indicated that your aircraft was second for an approach to Runway 06L; under these circumstances, the flight should be continued along the route that normally would have been expected under radar vectoring. In some cases of communications failure, pilots may need to revert to dead reckoning navigation (DR) to the final approach course. It is important to other aircraft and ATC for the aircraft experiencing a communications failure to continue the flight along a route that would permit the aircraft to conduct a straight-in approach and landing without unexpected manoeuvring. Pilots are expected to exercise good judgment in these cases. Unexpected manoeuvres, such as turns away from the final approach course, may cause traffic disruptions and conflicts.
  • If the communications failure occurs while being vectored at a radar vectoring altitude that is lower than a published IFR altitude (e.g., minimum sector altitude 25 NM), the pilot shall immediately climb to and maintain the appropriate minimum IFR altitude until arrival at a fix associated with the instrument procedure.

North Atlantic Exceptions

[ICAO NAT Doc 007, ¶6.6.1] Rules and procedures for the operation of an aircraft following a radio communications failure (RCF) are established to allow ATC to anticipate that aircraft’s subsequent actions and thus for ATC to be able to provide a service to all other flights within the same vicinity, so as to ensure the continued safe separation of all traffic. The general principles of such rules and procedures are set out in Annexes 2 and 10 to the ICAO Convention. States publish in their AIPs specific RCF rules and regulations to be followed within their particular sovereign airspace.

[ICAO NAT Doc 007, ¶6.6.2] It must be recognised that there is in general an underlying premise in “normal” radio communications failure procedures that they are for use when a single aircraft suffers an on-board communications equipment failure. Within the NAT Region and some adjacent domestic airspace (e.g. Northern Canada), where HF Voice is used for air-ground ATC communications, ionospheric disturbances resulting in poor radio propagation conditions can also interrupt these communications. While it is impossible to provide guidance for all situations associated with an HF communications failure, it is, however, extremely important to differentiate between two distinct circumstances: - firstly, an on-board communications equipment failure, resulting in an individual aircraft losing HF communications with ATC and; secondly, the occurrence of poor HF propagation conditions (commonly referred to as “HF Blackouts”), which can simultaneously interrupt HF air-ground communications for many aircraft over a wide area.

[ICAO NAT Doc 007, ¶6.6.4] However, the occurrence of poor HF propagation conditions can simultaneously interrupt HF air-ground communications for many aircraft over a wide area and ATC may then be unable to make any interventions to assure safe traffic separations using HF. Notwithstanding the growing use of Data link and SATCOM Voice for regular air-ground ATS communications in the NAT Region, all pilots must recognise that, pending the mandatory carriage and use of such means, an HF blackout will impact the ability of ATC to ensure the safe separation of all traffic. Hence, even if using other than HF for regular communications with ATC, pilots should still exercise appropriate caution when HF blackout conditions are encountered.

[ICAO NAT Doc 007, ¶6.6.5] The following procedures are intended to provide general guidance for aircraft which experience a communications failure while operating in, or proposing to operate in, the NAT Region. These procedures are intended to complement and not supersede State procedures/regulations.

General Provisions

  1. The pilot of an aircraft experiencing a two-way ATS communications failure should operate the SSR Transponder on identity Mode A Code 7600 and Mode C.
  2. When so equipped, an aircraft should use Satellite Voice Communications to contact the responsible aeradio station via special telephone numbers/short codes published in State AIPs (see also “HF Management Guidance Material for the NAT Region”). However, it must be appreciated that pending further system developments and facility implementations the capability for Ground(ATC)-initiated calls varies between different NAT OACs.
  3. This is a bit of change. In the past we were told SATVOICE was a convenience that might be okay if the controlling agency had the time for it. Now we are told this is our first means of alternate communication.

  4. If the aircraft is not equipped with SATCOM Voice then the pilot should attempt to use VHF to contact any (other) ATC facility or another aircraft, inform them of the difficulty, and request that they relay information to the ATC facility with which communications are intended.
  5. The inter-pilot air-to-air VHF frequency, 123.45 MHz, may be used to relay position reports via another aircraft. (N.B. The emergency frequency 121.5 MHz should not be used to relay regular communications, but since all NAT traffic is required to monitor the emergency frequency, it may be used, in these circumstances, to establish initial contact with another aircraft and then request transfer to the inter-pilot frequency for further contacts).
  6. In view of the traffic density in the NAT Region, pilots of aircraft experiencing a two-way ATS communications failure should broadcast regular position reports on the inter-pilot frequency (123.45 MHz) until such time as communications are re-established.

Communications Procedures for Use in the Event of an On-board HF Equipment Failure

[ICAO NAT Doc 007, ¶6.6.6] Use SATCOM Voice communications, if so equipped. (See General Provisions 2. above).

[ICAO NAT Doc 007, ¶6.6.7] If not SATCOM Voice equipped try VHF relay via another aircraft (See General Provisions 3. & 4 above).

Communications Procedures for Use during Poor HF Propagation Conditions

[ICAO NAT Doc 007, ¶6.6.8] Poor HF propagation conditions are the result of ionospheric disturbances. These are usually caused by sun-spot or solar flare activity creating bursts of charged particles in the solar wind which can spiral down around the Earth’s magnetic lines of force and distort or disturb the ionised layers in the stratosphere which are utilised to refract HF radio waves. As with the Aurora Borealis, which is of similar origin, these ionospheric disturbances most commonly occur in regions adjacent to the Magnetic Poles. Since the Earth’s North Magnetic Pole is currently located at approximately 87N 150W, flights through the North Atlantic and Northern Canada regions can, on occasion, experience resulting HF communications difficulties.

[ICAO NAT Doc 007, ¶6.6.9] SATCOM Voice communications are unaffected by most ionospheric disturbances. Therefore, when so equipped, an aircraft may use SATCOM Voice for ATC communications (See General Provisions 2 above).

[ICAO NAT Doc 007, ¶6.6.10] If not SATCOM Voice equipped, in some circumstances it may be feasible to seek the assistance, via VHF, of a nearby SATCOM Voice equipped aircraft to relay communications with ATC (See General Provisions 3. & 4. above).

[ICAO NAT Doc 007, ¶6.6.11] Whenever aircraft encounter poor HF propagation conditions that would appear to adversely affect air-ground communications generally, it is recommended that all pilots then broadcast their position reports on the air-to-air VHF frequency 123.45 MHz. Given the density of traffic in the NAT Region and the fact that in such poor propagation conditions ATC will be unable to maintain contact with all aircraft, it is important that even those aircraft that have been able to establish SATCOM Voice contact also broadcast their position reports.

[ICAO NAT Doc 007, ¶6.6.12] If for whatever reason SATCOM Voice communications (direct or relayed) are not possible, then the following procedures may help to re-establish HF communications. Sometimes these ionospheric disturbances are very wide-spread and HF air-ground communications at all frequencies can be severely disrupted throughout very large areas (e.g. simultaneously affecting the whole of the NAT Region and the Arctic.). However, at other times the disturbances may be more localised and/or may only affect a specific range of frequencies.

[ICAO NAT Doc 007, ¶6.6.13] In this latter circumstance, HF air-ground communications with the intended aeradio station may sometimes continue to be possible but on a frequency other than either the primary or secondary frequencies previously allocated to an aircraft. Hence, in the event of encountering poor HF propagation conditions pilots should first try using alternative HF frequencies to contact the intended aeradio station.

[ICAO NAT Doc 007, ¶6.6.14] However, while the ionospheric disturbances may be severe, they may nevertheless only be localized between the aircraft’s position and the intended aeradio station, thus rendering communications with that station impossible on any HF frequency. But the aeradio stations providing air-ground services in the NAT Region do co-operate as a network and it may, even then, still be possible to communicate with another aeradio station in the NAT network on HF and request that they relay communications. Efforts should therefore be made to contact other NAT aeradio stations via appropriate HF frequencies.

[ICAO NAT Doc 007, ¶6.6.15] Nevertheless, as previously indicated, there are occasions when the ionospheric disturbance is so severe and so widespread that HF air-ground communications with any aeradio station within the NAT Region network are rendered impossible.

Rationale for Lost Communications Operational Procedures

[ICAO NAT Doc 007, ¶6.6.16] Because of the density of oceanic traffic in the NAT Region, unique operational procedures have been established here to be followed by pilots whenever communications are lost with ATC. These procedures and the rationale for their development follow.

Tactical ATC Environment

[ICAO NAT Doc 007, ¶6.6.17] In a tactical ATC environment, such as one in which ATS Surveillance and VHF voice communications are used, ATC has continuous real-time data on the position/progress of all relevant traffic and the intentions of any individual aircraft with which ATC may have lost communications can be inferred from that aircraft’s filed flight plan. Hence, in such an environment, when voice communications with a single aircraft fail, the relevant published “lost comms procedures” normally require that aircraft to “land at a suitable aerodrome or continue the flight and adjust level and speed in accordance with the filed flight plan”. Communications blackouts affecting multiple aircraft, are not a feature of this type of VHF environment and hence in these circumstances, if required, ATC will be able to re-clear other traffic to ensure safe separations are maintained.

This is in accordance with ICAO rules. Despite protestations otherwise (see Accident Case Study / EMB 135BJ & Gol 1907), the "filed flight plan" means the one you sent to ATC before you left the ground. But note that in the North Atlantic region, this is only the case in a "tactical environment," one where ATC has you in radar and VHF contact. There is a North Atlantic exception . . .

Procedural ATC Environment

[ICAO NAT Doc 007, ¶6.6.18] However, in a (largely) non-ATS surveillance environment such as the North Atlantic, ATC must rely significantly upon the HF Voice Position Reports communicated by each aircraft for position, progress and intent data. Communications equipment failures and/or poor propagation conditions can interrupt the provision of this information. Therefore, to mitigate against such occurrences in the busy NAT HLA, outside of VHF coverage, ATC often employs strategic traffic planning and issues Oceanic Clearances which have been pre-co-ordinated with downstream OACs. Flights that continue to follow such a pre-coordinated strategic oceanic clearance are thereby guaranteed conflict-free progress to oceanic exit, even if no ATS communications are subsequently possible with any one, or even with all, of those strategically planned aircraft.

[ICAO NAT Doc 007, ¶6.6.19] Every effort is made by the initial NAT OAC to clear aircraft as per their filed flight plans. However, this is not always possible, particularly during peak traffic flow periods. Aircraft may receive clearances at flight levels or speeds other than those flight planned or, less frequently, may be cleared on oceanic tracks via entry or exit points other than those contained in the filed flight plan. Also it must be recognized that while a filed NAT flight plan may contain one or more step climbs for execution within the NAT Region, the initially issued oceanic clearance, or even any subsequently updated clearance (i.e. reclearance), has only been coordinated for a single (i.e. initial or current) flight level. It must therefore be appreciated that it is only the flight routing and profile contained in the last received clearance that ATC has probed for conflicts. Unless this clearance is precisely the same as the filed flight plan, in any lost communications situation in the NAT Region, if a pilot in receipt of a clearance unilaterally reverts to his/her filed flight plan (even by simply executing a later step climb), then no guarantee of conflict-free progress exists. Consequently, if a NAT aircraft loses the possibility of communications with the relevant OAC at any time after receiving and acknowledging a clearance, and the pilot elects to continue the flight, then the aircraft must adhere strictly to the routing and profile of the last received clearance until exiting the NAT Region. Pilots must not unilaterally revert to their filed flight plan.

If you are not in radar contact and were not in VHF communications, the rules in the North Atlantic change. Now you must continue along your last clearance. If you filed flight plan had a step climb in it, too bad. You cannot revert to the filed flight plan.

Operational Procedures following Loss of HF Communications Prior to Entry into the NAT

On-Board HF Communications Equipment Failure

[ICAO NAT Doc 007, ¶6.6.20] Due to the potential length of time in oceanic airspace, it is strongly recommended that a pilot, experiencing an HF communications equipment failure prior to entering the NAT, whilst still in domestic airspace and still in VHF contact with the domestic ATC Unit, does not enter NAT airspace but adopts the procedure specified in the appropriate domestic AIP and lands at a suitable airport. Should the pilot, nevertheless, elect to continue the flight then every effort must be made to obtain an oceanic clearance and the routing, initial level and speed contained in that clearance must be maintained throughout the entire oceanic segment. Any level or speed changes required to comply with the Oceanic Clearance must be completed within the vicinity of the oceanic entry point.

[ICAO NAT Doc 007, ¶6.6.21] If, however, an oceanic clearance cannot be obtained, the individual aircraft suffering radio communications equipment failure should enter oceanic airspace at the first oceanic entry point, level and speed contained in the filed flight plan and proceed via the filed flight plan route to landfall. The initial oceanic level and speed included in the filed flight plan must be maintained until landfall. Any subsequent step-climbs included in the filed flight plan must not be executed.

HF Blackout

[ICAO NAT Doc 007, ¶6.6.22] In the case of aircraft that lose ATC communications as a result of poor propagation conditions (HF Blackouts) when approaching NAT airspace through domestic airspace where ATC communications are also conducted via HF (e.g. entering the NAT through Northern Canadian airspace into the Reykjavik OCA), it is probably less advisable to execute unscheduled landings. These poor propagation conditions are very likely to affect many aircraft simultaneously and multiple diversions of “lost comms” aircraft might create further difficulties and risks.

[ICAO NAT Doc 007, ¶6.6.23] As with the equipment failure situation, aircraft approaching the NAT and losing ATC communications as a result of poor HF radio propagation conditions should, if already in receipt of an oceanic clearance, follow the routing specified in that clearance and maintain the initial cleared level and speed throughout the oceanic segment i.e. through to landfall.

[ICAO NAT Doc 007, ¶6.6.24] However, in these HF Blackout circumstances, if no oceanic clearance has been received, the aircraft must remain at the last cleared domestic flight level, not only to the ocean entry point but also throughout the whole subsequent oceanic segment (i.e. until final landfall). This is in stark contrast to the equipment failure case. In such HF Blackouts, pilots must not effect level changes to comply with filed flight plans. Such aircraft should, maintain the last cleared level and, enter oceanic airspace at the first oceanic entry point and speed contained in the filed flight plan, then proceed via the filed flight plan route to landfall.

[ICAO NAT Doc 007, ¶6.6.25] The rationale here must be appreciated. In such circumstances it is likely that ATC will have simultaneously lost HF communications with multiple aircraft in the same vicinity. Should pilots then wrongly apply the “normal” radio failure procedures and “fly the flight plan”, there is a possibility that two such aircraft may have filed conflicting flight paths/levels through the subsequent oceanic airspace, and without communications with either aircraft, ATC would then be unable to intervene to resolve the conflict. Since safe aircraft level separation assurance has already been incorporated into the current domestic clearances, it is consequently imperative that under such (Domestic and Oceanic) HF-blackout circumstances, all aircraft electing to continue flight into NAT oceanic airspace without a received and acknowledged oceanic clearance, should adhere to the flight level in the last received domestic clearance. No level changes should be made to comply with a filed oceanic level that is different from that of the domestic clearance in effect at the time that ATC air-ground communications were lost.

Operational Procedures following Loss of HF Communications after Entering the NAT

[ICAO NAT Doc 007, ¶6.6.26] If the HF communications equipment failure occurs or HF Blackout conditions are encountered after entering the NAT then:

  • The pilot must proceed in accordance with the last received and acknowledged Oceanic Clearance, including level and speed, to the last specified oceanic route point (normally landfall).
  • After passing this point, the pilot should conform with the relevant AIP specified State procedures/regulations and if necessary rejoin the filed flight plan route by proceeding, via the published ATS route structure where possible, to the next significant point contained in the filed flight plan.
  • Note: the relevant State procedures/regulations to be followed by an aircraft in order to rejoin its filed Flight Plan route are specified in detail in the appropriate State AIP.

[ICAO NAT Doc 007, ¶6.6.27] Aircraft with a destination within the NAT Region should proceed to their clearance limit and follow the ICAO standard procedure to commence descent from the appropriate designated navigation aid serving the destination aerodrome at, or as close as possible to, the expected approach time. Detailed procedures are promulgated in relevant State AIPs.

Summary of Operational Procedures Required following Loss of Air/Ground ATS Communications in the NAT Region

[ICAO NAT Doc 007, ¶6.6.28] The foregoing detailed operational procedures can be simply summarised as follows:

  • Equipment Failure before receiving an Oceanic Clearance:- Divert or fly the Flight Plan route, speed and initial planned oceanic level to landfall.
  • Blackout encountered (in an HF comms Domestic ATC environment) before receiving an Oceanic Clearance:- Continue at Domestic cleared level and follow flight planned route and speed to landfall.
  • Equipment Failure or Blackout after receiving an Oceanic Clearance:- Fly that clearance to landfall.

In all cases, after landfall rejoin, or continue on, the flight planned route, using appropriate State AIP specified procedures for the domestic airspace entered.

Pacific Exceptions

[ICAO Doc 7030, PAC 9.3)

In the event of total loss of communication, an aircraft shall:

a) try to re-establish communication by all other means;

b) if all attempts to re-establish communication with ATC are unsuccessful:

1) squawk 7600;

2) if able, broadcast in the blind at suitable intervals: flight identification, flight level, aircraft position (including the ATS route designator or the track code) and intentions on the frequency in use, as well as on frequency 121.5 MHz (or, as a back-up, the VHF inter-pilot air-to-air frequency 123.45 MHz);

3) watch for conflicting traffic both visually and by reference to airborne collision avoidance systems or traffic displays (if equipped);

4) turn on all aircraft exterior lights (commensurate with appropriate operating limitations);

5) maintain the last assigned speed and level for a period of 60 minutes following the aircraft's failure to report its position over a compulsory reporting point (including ADS-C flights), and thereafter adjust speed and altitude in accordance with the filed flight plan;

Note.— In airspace where the strategic lateral offset procedures (SLOP) has been authorized, aircraft experiencing communication failure may also elect to initiate SLOP in accordance with State AIP, including an offset of 1.8 or 3.7 km (1 NM or 2 NM) right of track.

6) Upon exiting oceanic airspace, conform to the relevant State procedures and regulations.

United States Exceptions

[14 CFR 91, §91.185]

(a) General. Unless otherwise authorized by ATC, each pilot who has two-way radio communications failure when operating under IFR shall comply with the rules of this section.

(b) VFR conditions. If the failure occurs in VFR conditions, or if VFR conditions are encountered after the failure, each pilot shall continue the flight under VFR and land as soon as practicable.

(c) IFR conditions. If the failure occurs in IFR conditions, or if paragraph (b) of this section cannot be complied with, each pilot shall continue the flight according to the following:

(1) Route.

(i) By the route assigned in the last ATC clearance received;

(ii) If being radar vectored, by the direct route from the point of radio failure to the fix, route, or airway specified in the vector clearance;

(iii) In the absence of an assigned route, by the route that ATC has advised may be expected in a further clearance; or

(iv) In the absence of an assigned route or a route that ATC has advised may be expected in a further clearance, by the route filed in the flight plan.

(2) Altitude. At the highest of the following altitudes or flight levels for the route segment being flown:

(i) The altitude or flight level assigned in the last ATC clearance received;

(ii) The minimum altitude (converted, if appropriate, to minimum flight level as prescribed in §91.121(c)) for IFR operations; or

(iii) The altitude or flight level ATC has advised may be expected in a further clearance.

(3) Leave clearance limit.

(i) When the clearance limit is a fix from which an approach begins, commence descent or descent and approach as close as possible to the expect-further-clearance time if one has been received, or if one has not been received, as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.

(ii) If the clearance limit is not a fix from which an approach begins, leave the clearance limit at the expect-further-clearance time if one has been received, or if none has been received, upon arrival over the clearance limit, and proceed to a fix from which an approach begins and commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.

Country and Airport Exceptions

Individual countries and even airports within the country may have their own peculiar routings and procedures to be used in the event of lost communications. Your Jeppesen manuals are your best source for this information but the location of the lost communications information is not consistent. You may find it on the individual airport briefing pages, the arrival/departure pages, the approach charts, or in the text pages. Among the text pages, you need to look at the ATC and Emergency pages.

The following, for example, comes from the "Emergency Procedures - Australia / ICAO Differences or State Special Procedures" page:


Note: This is just page one of three pages for Australia.

Satellite phones

Some ARINC centers allow position reports via phone lines. The person answering the phone is a radio operator and expects the normal position reporting format. The phone number is on some en route charts and the Jeppesen Airway Manual En Route pages (check current en route chart to ensure the number is current): [Jeppesen Airway Manual En Route page 101]

ARINC Center / Direct Dial / INMARSAT Code
SFO / 925-371-3920 / 436625
NYC / 631-244-2492 / 436623
Shanwick / 9-011-44-1292-692663
Gander / 1-709-651-5212

Some Satcom providers have direct lines to various radio stations. Satcom-Direct, for example, offers the following:

See Also:

14 CFR 91, Title 14: Aeronautics and Space, General Operating and Flight Rules, Federal Aviation Administration, Department of Transportation

Canadian Aviation Regulations, Transport Canada.

ICAO Annex 2 - Rules of the Air, International Standards, Annex 2 to the Convention on International Civil Aviation, July 2005

ICAO Annex 10 - Vol II - Communication Procedures, International Standards and Recommended Practices, Annex 10 to the Convention on International Civil Aviation, Vol II, October 2001

ICAO Doc 7030 - Regional Supplementary Procedures, International Civil Aviation Organization, 2008

ICAO Doc 7030, Amendment 1, International Civil Aviation Organization, 8 January 2009

Jeppesen Airways Manuals

ICAO NAT Doc 007, North Atlantic Operations and Airspace Manual, v 2018-1

Transport Canada Aeronautical Information Manual. Note: this link changes frequently, you may need to drill up a level: Transport Canada Civil Aviation Publications