Article 7Contingency requirements
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 F1CAA and shall make available, through the IC allocation system, the related information to the other Mode S operators.