The UK Civil Aviation Authority's ongoing regulatory impact assessment on a potential requirement for all aircraft to be fitted with Mode S transponders continues to raise hackles in the UK general aviation leisure flying sector.

The CAA argues that the pressures on airspace from rising traffic provide an imperative, either to extend controlled airspace or to fit light aircraft and gliders with transponders that enable airborne collision avoidance systems (ACAS) to "see" them, and so that accurate traffic advisories can be provided to aircraft using radar services. The agency has had promising responses from the avionics industry to its request for the development of a lightweight, low-cost Mode S transponder.

Source: Flight International