Communication Failure Procedure

7/28/2019 Communication Failure Procedure

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Article Information

Category:Air GroundCommunication

Contentsource:

SKYbrary

Contentcontrol:

EUROCONTROL

Communication Failure: Guidance forControllers

ategories:Air Ground Communication |Aircraft Emergency and Unusual Situations

This article is based on ICAO provisions regarding

ommunication failure as well as on best practice identified byEUROCONTROL.

here is no set of ready "out-of-the-box" rules to be followedniversally. As with any unusual or emergency situation,ontrollers should exercise their best judgment and expertise

when dealing with the consequences related to radioommunication failure (RCF) to aircraft in any stage of flight.generic checklist for handling unusual situations is readily

vailable from EUROCONTROL but it is not intended to bexhaustive and is best used in conjunction with local ATCrocedures.

Contents

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1 Description2 Useful to Know3 Anticipated Impact on Crew4 What to Expect5 What to Provide

5.1 Partial Communication Failure5.2 Complete Communication Failure

6 ASSIST Principle7 Defences8 Related Articles9 Further Reading

Description

his article provides guidance for controllers on what to expect and how to act when dealing with onboaRCF situations. There are some considerations which will enable the controller, not only to provide as muupport as possible to the aircraft concerned, but also maintain the safety of other aircraft in the vicinitynd of the ATC service provision in general.

Useful to Know

Radio communication failure is an eventuality that pilots as well as air traffic controllers are well preparemanage. Although the complete loss of communication is an extremely rare event due to duplication ofquipment, there are several areas which contribute most commonly to full or partial communicationreakdown:

Airborne or ground radio equipment malfunction;
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ry.aero/index.php/Communication_Failure:_Guidance_for_Controllers#http://www.skybrary.aero/index.php/EUROCONTROLhttp://www.skybrary.aero/index.php/Emergency_or_Abnormal_Situationhttp://www.skybrary.aero/index.php/Category:Aircraft_Emergency_and_Unusual_Situationshttp://www.skybrary.aero/index.php/Category:Air_Ground_Communicationhttp://www.skybrary.aero/index.php/Special:Categorieshttp://www.skybrary.aero/index.php/EUROCONTROLhttp://www.skybrary.aero/index.php/About_SKYbraryhttp://www.skybrary.aero/index.php/Category:Air_Ground_Communication


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Sleeping Receiver;Stuck microphone selector.

t is important to note that the applicable RCF procedures are expected to conform to the established ICSARPS) and Procedures (See the list of ICAO documents in Further Reading; for detailed list of factors aircumstances leading to RCF, see the dedicated SKYbrary article: Loss of Communication)

Anticipated Impact on Crew

wide range of practical problems could arise following RCF:

Crew may not be immediately aware of the communication loss;Increased workload in the cockpit - crew must determine the time the RCF occurred and actaccordingly by:

attempting to establish radio telephony (RT) contact on the last frequency and other radiofrequencies established for the flight route;attempting to establish RT contact with other aeronautical stations or aircraft or attempting toestablish communication with the relevant ATC unit by any alternate available means;if RT contact cannot be established with the responsible ATC, the crew will follow procedures RCF failure as described by their operational manual and all other applicable documents;adherence to the appropriate RCF emergency procedures depending on the flight conditions -

VMC or IMC.

What to Expect

he aircraft shall comply with the voice communication failure procedures of Annex 10, Volume II, and wuch of the following procedures as are appropriate. The aircraft shall attempt to establish communicatio

with the appropriate air traffic control unit using all other available means. In addition, the aircraft, whenorming part of the aerodrome traffic at a controlled aerodrome, shall keep a watch for such instructions

may be issued by visual signals.

n aircraft equipped with an SSR transponder is expected to operate the transponder on Mode A Code 7

o indicate that it has experienced air-ground communication failure. AnADS-B equipped aircraftxperiencing radiocommunication failure may transmit the appropriate ADS-B emergency and/or urgency

mode. An aircraft equipped with other surveillance system transmitters, including ADS-C, might indicate oss of air-ground communication by all of the available means.

f the aircraft fails to indicate that it is able to receive and acknowledge transmissions, separation shall bmaintained between the aircraft having the communication failure and other aircraft, based on thessumption that the aircraft will:

InVMC:1. Continue to fly in visual meteorological conditions;2. Land at the nearest suitable aerodrome; and

3. Report the arrival by the most expeditious means to the appropriate air traffic control unitIn IMC or when conditions are such that it does not appear likely that the pilot will complete theflight in accordance with the prescribed VMC RCF procedures above:

1. Unless otherwise prescribed on the basis of a regional air navigation agreement, in airspacewhere procedural separation is being applied, maintain the last assigned speed and level, orminimum flight altitude if higher, for a period of 20 minutes following the aircrafts failure toreport its position over a compulsory reporting point and thereafter adjust level and speed inaccordance with the filed flight plan; or

2. In airspace where an ATS surveillance system 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 ominutes following:
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i) The time the last assigned level or minimum flight altitude is reached; orii) Time the transponder is set to Code 7600 or the ADS-B transmitter is set to indicate loss of air-ground communications; oriii) The aircrafts failure to report its position over a compulsory reporting point;whichever is later and thereafter adjust level and speed in accordance with the filed fligplan;

3. When being vectored or having been directed by ATC to proceed offset using RNAV without aspecified limit, proceed in the most direct manner possible to rejoin the current flight plan rou

no later than the next significant point, taking into consideration the applicable minimum flighaltitude;4. Proceed according to the current flight plan route to the appropriate designated navigation ai

fix serving the destination aerodrome and, when required to ensure compliance with 5), holdover this aid or fix until commencement of descent;

5. Commence descent from the navigation aid or fix specified in 4) at, or as close as possible tothe expected approach time last received and acknowledged; or, if no expected approach timhas been received and acknowledged, at, or as close as possible to, the estimated time of arresulting from the current flight plan;

6. Complete a normal instrument approach procedure as specified for the designated navigationor fix; and

7. Land, if possible, within 30 minutes after the estimated time of arrival specified in 5) or the la

acknowledged expected approach time, whichever is later.

What to Provide

When first indications for probable RCF are received, the controllers should determine whether the event

Partial communication failure (one way RCF), orComplete communication failure (two way RCF) by

etermining whether or not the aircrafts receiver is functioning by instructing the aircraft on the channelar used to acknowledge by executing a specified manoeuvre which can be observed on the ATSurveillance system display, or to transmit, if possible, a specified signal in order to indicatecknowledgement (e.g. instructing the aircraft to activate IDENT or to squawk specified SSR code and/oDS-B transmission changes).

f the action prescribed above is unsuccessful, it shall be repeated on any other available channel on whis believed that the aircraft might be listening, including the emergency frequency 121.5 Mhz channel.

Partial Communication Failure

Where it has been established that the aircrafts radio receiver is functioning, continued control can beffected using SSR code/ADS-B transmission changes or IDENT transmissions to obtain acknowledgemenf clearances issued to the aircraft.

ny manoeuvring instructions shall be such that the aircraft would regain its current cleared track afteraving complied with the instructions received. Special attention to avoid misinterpretation should be pa

when the aircraft is located near an airway turn.

Complete Communication Failure

When a controlled aircraft experiencing complete communication failure is operating or expected to opern an area and at flight levels where an ATS surveillance service is applied, separation minima based on urveillance systems may continue to be used.
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owever, if the aircraft experiencing the communication failure is not identified, separation shall be applietween identified aircraft and all unidentified aircraft observed along the expected route of the aircraft whe communication failure, until such time as it is known, or can safely be assumed, that the aircraft witadiocommunication failure has passed through the airspace concerned, has landed, or has proceededlsewhere.

ction taken to ensure suitable separation shall cease to be based on the assumption that the aircraftollows ICAO SARPs when:

it is determined that the aircraft is following a procedure differing from ICAO SARPs (VMC and IMCRCF procedures above)through the use of electronic or other aids, air traffic control units determine that action differing frthat required by VMC and IMC RCF procedures may be taken without impairing safety; orpositive information is received that the aircraft has landed.

s soon as it is known that two-way communication has failed, appropriate information describing thection taken by the air traffic control unit, or instructions justified by any emergency situation, shall beransmitted blind* for the attention of the aircraft concerned, on the frequencies available on which theircraft is believed to be listening, including the voice frequencies of available radio navigation or approaids. Information shall also be given concerning:

meteorological conditions favourable to a cloud-breaking procedure in areas where congested traffmay be avoided; andmeteorological conditions at suitable aerodromes.

ertinent information shall be given to other aircraft in the vicinity of the presumed position of the aircrafxperiencing the failure.

s soon as it is known that an aircraft which is operating in its area of responsibility is experiencing anpparent RCF, an air traffic services unit shall forward information concerning the RCF to all air trafficervices units concerned along the route of flight. The ACC in whose area the destination aerodrome isocated shall take steps to obtain information on the alternate aerodrome(s) and other relevant informatpecified in the filed flight plan, if such information is not available.

f circumstances indicate that a controlled flight experiencing a communication failure might proceed toone of) the alternate aerodrome(s) specified in the filed flight plan, the air traffic control unit(s) serving lternate aerodrome(s) and any other air traffic control units that might be affected by a possible divershall be informed of the circumstances of the failure and requested to attempt to establish communicatio

with the aircraft at a time when the aircraft could possibly be within communication range. This shall apparticularly when, by agreement with the operator or a designated representative, a clearance has beenransmitted blind to the aircraft concerned to proceed to an alternate aerodrome, or when meteorologicaonditions at the aerodrome of intended landing are such that a diversion to an alternate is consideredkely.

When an air traffic control unit receives information that an aircraft, after experiencing a communicationailure has re-established communication or has landed, that unit shall inform the air traffic services unit

whose area the aircraft was operating at the time the failure occurred, and other air traffic services unitsoncerned along the route of flight, giving necessary information for the continuation of control if theircraft is continuing in flight.

ASSIST Principle

est practices identified by EUROCONTROL and embedded in the ASSIST principle could be followed (Acknowledge; S - Separate, S - Silence; I - Inform, S - Support, T - Time) by air traffic controllers in caf RCF:
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A - acknowledge the RCF, determine if it is a partial or complete RCF;S - separate the aircraft (accordingly, identified vs. unknown traffic) and if necessary, allow long finkeep the active runway clear of departures, arrivals and vehicles;S - silence the non-urgent calls (as required), look for means to establish possible relay by otherstationsI - inform the supervisor and all concerned ATC units as well as airport authorities at the destinatioor alternative aerodromeS - support the flight by transmitting blind and providing any information considered necessary sucas type of approach, runway length and aerodrome details, etc.

T - provide time for the crew to assess the situation and adhere to the RCF procedures

Defences

When known that an aircraft which is operating in the area of responsibility is experiencing an apparentRCF, be ready to:

As Approach/Departure controller: action to be taken by an aircraft experiencing air-groundcommunication failure in the event the aircraft has been radar vectored away from the route specifin its current flight plan to comply with the one prescribed on the basis of a regional air navigationagreement and included in the SID description or published in AIPs. This scenario is valid whereclearances for departing aircraft containing no time or geographical limit for an initial or intermedialevel are used.

As Area/Enroute controller: During the application of the 93 km (50 NM) separation, when an aircrafails to report its position, take action within 3 minutes to establish communication. If communicathas not been established within 8 minutes of the time the report should have been received, takeaction to apply an alternative form of separation. (ICAO requirements for applying longitudinaldistance-based separation minima in an RNP environment not using ADS-C)Make use of other aircraft to relay messages when you believe aircraft is operating at extreme rangor in conditions of poor propagation.If attempts to restore two-way communications with the aircraft are unsuccessful, inform theappropriate military authorities. Keep the military authorities informed of action taken by the ATS uas well as any further action intended.

As Tower controller: transmit an ARR (arrival) message:for a landing at the destination aerodrome:

to all ATS units concerned with the flight during the period of the communication failureandto all other ATS units which may have been alerted;

for a landing at an aerodrome other than the destination aerodrome:to the ATS unit serving the destination aerodrome; this unit shall then transmit an ARRmessage to other ATS units concerned with the flight during the period of thecommunication failure.

Notes of the SKYbrary Editor *Blind transmission- a transmission from one station to another inircumstances where two-way communication cannot be established but where it is believed that the catation is able to receive the transmission.

Related Articles

Loss of CommunicationProlonged loss of communication

ADS-BCommunication Equipment Technical ProblemsSleeping ReceiverStandard PhraseologyRead-back or Hear-back
http://www.skybrary.aero/index.php/Loss_of_Communicationhttp://www.skybrary.aero/index.php/Prolonged_loss_of_communicationhttp://www.skybrary.aero/index.php/ADS-Bhttp://www.skybrary.aero/index.php/Communication_Equipment_Technical_Problemshttp://www.skybrary.aero/index.php/Sleeping_Receiverhttp://www.skybrary.aero/index.php/Standard_Phraseologyhttp://www.skybrary.aero/index.php/Read-back_or_Hear-backhttp://www.skybrary.aero/index.php/Read-back_or_Hear-backhttp://www.skybrary.aero/index.php/Standard_Phraseologyhttp://www.skybrary.aero/index.php/Sleeping_Receiverhttp://www.skybrary.aero/index.php/Communication_Equipment_Technical_Problemshttp://www.skybrary.aero/index.php/ADS-Bhttp://www.skybrary.aero/index.php/Prolonged_loss_of_communicationhttp://www.skybrary.aero/index.php/Loss_of_Communication


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Further Reading

ALLCLEAR? Toolkit

CAO

Annex 2 - Rules of the Air, paragraph 3.6.5.2 Communication failureDoc 4444 Air Traffic Management (PANS-ATM) (Especially 15.3 Air-Ground Communication Failure

8.8.3 Failure of equipment)Doc 8168, Aircraft Operations (PANS-OPS) - Flight Procedures - Volume 1 (Especially 1.5Communication Failure Procedures)Doc 7030 EUR Regional Supplementary Procedures (SUPPS) (6.2.4.2)

UROCONTROL

Guidelines for Controller Training in the Handling of Unusual/Emergency Situations, EUROCONTROLAGC Briefing Note 3 - Loss of CommunicationInvestigation into Loss of Communication
http://www.skybrary.aero/index.php/Solutions:ALLCLEARhttp://www.skybrary.aero/bookshelf/books/15.pdfhttp://www.skybrary.aero/bookshelf/books/111.pdfhttp://www.skybrary.aero/bookshelf/books/826.pdfhttp://www.skybrary.aero/bookshelf/books/826.pdfhttp://www.skybrary.aero/bookshelf/books/111.pdfhttp://www.skybrary.aero/bookshelf/books/15.pdfhttp://www.skybrary.aero/index.php/Solutions:ALLCLEAR

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Communication Failure Procedure