Two US labour organisations are calling for collision-avoidance systems to be compulsory on freighter aircraft. In a separate move, US freight carriers are promoting a change directly to global-positioning-system (GPS)-based automatic-dependent-surveillance- broadcast (ADS-B).

The US Teamsters union, which represents many airline employees, including cabin crew, and the US Independent Pilots Association, representing the pilots of US freight carrier UPS, have called for the US Federal Aviation Administration to end the regulatory anomaly which allows cargo aircraft of any size to operate without traffic-alert and collision-avoidance systems (TCAS). The system is compulsory for passenger-carrying commercial airliners. In Europe, TCAS or an equivilant will be mandatory from 2000.

UPS is leading the push for the adoption of GPS-based ADS-B for collision-avoidance purposes, reports Flight International's sister publication Air Navigation International. The US Air Freight Association (AFA) is discussing with the FAA, a proposal to allow cargo aircraft to use ADS-B. The AFA believes that the ADS-B could rapidly provide a collision-avoidance function equivalent to the TCAS I, then evolve to a system comparable to the TCAS II and provide full ADS-B capabilities when that concept is ready for widespread implementation.

While the TCAS relies on Mode-S data linking, the ADS-B uses GPS data, and is seen as the basis for the "free-flight" airspace concept. The concept is still some way from being introduced into service, but UPS says that the necessary technology is available.

Meanwhile UPS is installing five Boeing 727-100QF freighters with TCAS, as the aircraft are being modified to be operated, as quick- change passenger aircraft. They also will be equipped with GPS receivers and head-up displays, making them Category 3A capable.

Air Navigation International reports that the US Air Force is the most likely candidate to launch the Boeing 757 future air- navigation system avionics programme, on VIP aircraft ordered this year.

Source: Flight International