# Commission Regulation (EC) No 262/2009 of 30 March 2009 laying down requirements for the coordinated allocation and use of Mode S interrogator codes for the single European sky (Text with EEA relevance), Article 7: Contingency requirements

Extent: E+W+S+N.I.

1. Air traffic service providers shall assess the possible impact on air traffic services of interrogator code conflicts, and the corresponding potential loss of Mode S target surveillance data from the impacted Mode S interrogators, taking into account their operational requirements and available redundancy.
2. Unless the potential loss of Mode S target surveillance data has been assessed to have no safety significance, Mode S operators shall:
(a) implement monitoring means to detect interrogator code conflicts caused by other Mode S interrogators impacting eligible Mode S interrogators they operate on any operational interrogator code;
(b) ensure that the interrogator code conflict detection provided by the implemented monitoring means is achieved in a timely manner and within a coverage that satisfy their safety requirements;
(c) identify and implement as appropriate, a fallback mode of operation to mitigate the possible interrogator code conflict hazards on any operational code, identified in the assessment referred to in paragraph 1;
(d) ensure that the implemented fallback mode of operation does not create any interrogator code conflict with other Mode S interrogators referred to by the interrogator code allocation plan.
3. Mode S operators shall report any identified interrogator conflict involving an eligible Mode S interrogator they operate on any operational interrogator code to the CAA and shall make available, through the IC allocation system, the related information to the other Mode S operators.

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Source: https://www.legislation.gov.uk/eur/2009/262/article/7 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-262/article-7
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.