Question NW2042 to the Minister of Transport

Reply:

South African Civil Aviation Authority (SACAA)

a (i) (ii) (iii) The Air Navigation Service Provider (ANSP) and in this case the Air Traffic and Navigation Services (ATNS) is required to maintain Air Navigation Systems (Instrument Landing Systems (ILS), Very High Frequency Omni-directional Radio Range (VOR) and Distance-Measuring Equipment (DME) in accordance with ICAO Standards and Recommended Practices, Part 171 of the Civil Aviation Regulations and the SA-CATS 171. One of the SA-CATS 171 requirements is that all Air Navigation Systems must be subjected to periodic flight calibration, which is 150 days for the ILS and one (1) year for the VOR and DME. Each stipulated period has an automatic tolerance of 30 days. On expiry of the tolerance period, the ANSP can apply for 25 days extension if flight calibration of the system is not possible and provided that the system proved to be stable during three (3) consecutive flight calibrations which were conducted by an approved Flight Inspection Organisation. If flight calibration of the system is still not possible after expiry of the extended period, the ANSP can apply for an exemption for a period not exceeding 180 days.

b) The ANSP is required to switch off any Air Navigation System which cannot be operated in accordance with the prescribed standards and notify all users of the facility to avoid its usage in air navigation. This may result in some airports being downgraded. In addition, a NOTAM must be published to notify air crews of the status of facilities in the airports so that they plan their flights safeiy in relation to this status. Lastly the result of switching off the ILSes at airports means that pilots may not be able to land at airports when there are inclement weather conditions. However, operations at the airports can continue as required as there are prescribed safety standards that must be followed by pilots.