Development of Further Policy on Radio Failure Procedures

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Development of Further Policy on Radio Failure Procedures

34TH ANNUAL CONFERENCE, Jerusalem, Israel, 27-31 March 1995

WP No. 83

Development of Further Policy on Radio Failure Procedures


The aim of the RTF policy is to reduce workload in the air and on the ground, through the development of simple, clear and standard procedures. These procedures, considered as basic for adoption in the event of RTF, should be collated and issued in a single ICAO document. Any other particular procedures for local application should be published in state AIP in conformity with an approved ICAO model, taking into account the necessity to produce a standardised format in single terms for both pilot and controller.

Today’s situation is quite different, and the recent ATS airspace classification’ has further need for clarification, hence the reason for this item on the work study programme.

The results of the questionnaire are substantially unchanged in respect of our former report contained in WP No. 94 Ottawa. They demonstrate the necessity of having a clear ICAO basic procedure particularly within lower airspace ( TMA’s and CTR’s). Evidence of this is by the large number of ‘specific’ national and/or local RTF procedures established in the vicinity of major airports, which generally follow principles contrary to the RTF procedures (e.g. descent in VMC for VFR traffic).

With reference to the ICAO regulation contained in Annex 2, Annex 10 and Doc 4444

The provision of ATC to other flights operating in the airspace where an RTF has occurred is based on the provision that the RTF aircraft will comply with Annex 2 para This is subject to IMC or marginal meteorological conditions only. Under the new ‘ ATS airspace classification’, the provisions of Doc 4444 (…..”separation shall be maintained….”) apply to VFR flights , when a VFR flight is operated as a controlled flight in class B,C,D. Annex, Annex 11 3.1.) According to Doc. 4444 and to the requirement that separation should always be applied, is therefore recommended that ICAO investigate the current set of RTF rules taking into account, among other above mentioned aspects, the different minima for VMC established for different airspace classification. Some interesting considerations can be expressed with reference to the all-classes application of RTF procedures in VMC when it occurs just after take off. May be, it should be necessary to ‘split’ the general rules and consider that ‘exceptions’ can be made for operation at particular aerodromes when so prescribed by the appropriate ATS authority (e.g. consideration of the ATC planning possibility offered by the three types of ‘ alternative aerodrome and their respective utilisation’). All pertinent Doc 4444 para (e.g. part III 17.8, 17.3, 17.5 ) should, accordingly be modified and/or integrated as deemed necessary by ICAO.

Forthcoming ( and somewhere ‘existing’) technology permits and more and more will permit the availability of primary and alternative means of ground-air-ground communication. (e.g. Mode S Data-link). This ‘state of the art ‘ ATC technology should be considered by ICAO to establish a common basic procedure to permit the implementation of some national regulations to comply with Doc 4444 part III 17.4 obligation (‘….a different action may be taken by ATC units through the use of electronic or other aids…… without impairing safety….’).

Finally, a clear distinction should also be made between radar and non-radar environment, for the RTF procedure application.

To Conclude

There appears to be a difference between the official ICAO RTF rules and the present situation in ATC, particularly with reference to the new ATS airspace classification and related procedure in RTF situation. Consideration should be given to RTF procedures in the lower airspace. ICAO basic procedures appear to be unspecified and generally not applicable, especially with regard to SVFR-VFR operated as controlled flight and IFR in VMC operating in the vicinity of a major airport. A new comprehensive set of RTF rules should be examined by ICAO, taking into account radar and non-radar environments as well as the ‘state of the art’ of ATC equipment. The use of specific electronic aids in order to resolve RTF should be investigated to permit the use of such technology by ATC in a safety manner. It is requested that Conference decide in light of the conclusions drawn as the results should be passed to ICAO for further action.

Last Update: September 28, 2020  

February 12, 2020   231   Jean-Francois Lepage    1995    

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