Sir -It is stated in the article "Wavionix speeds up design of air-traffic flight patterns" (Flight International, 24-30 January, P23) that en route airways flightpaths are designed according to criteria laid down by the International Civil Aviation Organisation (ICAO) aircraft operations manual.

ICAO Document 8168 - Procedures for Air Navigation Services: Aircraft Operations (PANS OPS) contains the criteria for the design and construction of visual and instrument flight procedures. The current edition of this document does not contain any criteria for the design and construction of en route airways flightpaths.

This has been a longstanding omission from the PANS OPS, although I understand that proposals for design criteria have been forwarded by the Air Navigation Commission to the ICAO Council.


Wellington, New Zealand

Source: Flight International