Graham Warwick/ATLANTA

US REGIONAL LONE Star Airlines is the launch customer for Lockheed Martin's autonomous precision-approach and landing system (APALS). The Fort Worth, Texas-based airline has signed a memorandum of understanding to equip its four Dornier 328 regional turboprops with the system, which uses the aircraft's radar to provide approach guidance (Flight International, 17-23 January).

Vice-president of flight operations Allen McGinnes says that the APALS is suited to Lone Star's role as a niche carrier developing new markets, which often involves serving airports equipped with non-precision approaches. Service reliability is a major factor in developing new markets, he says, requiring the ability to continue operations in reduced visibility.

McGinnes expects the APALS to enable autonomous Category I precision approaches at non-precision airports and Category II approaches at Cat I airports. The airline's 328s will be equipped with a Cat II-certificated APALS driving the aircraft's Honeywell flight-director.

Lone Star hopes to equip its 328s by mid-year with pre-production units to begin gathering the synthetic-aperture-radar maps which comprise the APALS approach databases. During an approach, ground scenes produced by the aircraft's radar are correlated with these maps to provide precise position updates to an inertial-navigation system.

Certification is expected by mid-1997. McGinnes expects Lone Star services to airports in Mexico and to ski resorts in Colorado to be the first to benefit from APALS introduction. He cites the difficult curved approach to Aspen, Colorado, as a prime candidate for the system.

Precision approaches will have to be developed for several of the airports, McGinnes says. Initially, these will be flown using the global-positioning system (GPS) for guidance, with the APALS acting as a GPS monitor, until the APALS has proved its reliability, he says.

Lockheed Martin is working with two European airlines, both flying the same type of narrowbody airliner, on plans to certificate a version of the APALS suitable for Cat III automatic landings.

Source: Flight International