Rockwell Collins announced the successful completion of microwave landing system (MLS) Category IIIb approach tests in the U.S. and Europe, with the aim of obtaining TSO approval for its multi-mode receiver (MMR) in the first quarter of this year. The single-box MMR, which can typically contain ILS, GPS and MLS precision landing guidance modules, is based on the internationally standardized avionics unit, which will be the future same-size replacement for today’s airline ILS receiver. The new design reflects the fact that tomorrow’s airports will offer ILS, GPS or MLS approaches–but rarely all three serving the same runway. The MMR allows pilots to select the landing guidance system appropriate to the runway in use.

Flown in Rockwell’s Cessna 206 and Sabreliner 50, the flight tests included more than 100 manual and auto-coupled Cat IIIb MLS approaches at 13 civil and military airports in the U.S. and Europe. U.S. airports included Savannah, Ga.; Pope AFB, N.C.; Atlantic City, N.J.; Wilmington, Del.; Cheyenne, Wyo.; Boise and Hailey, Idaho; North Bend, Ore.; and Wenatchee, Moses Lake and Pullman, Wash. European airports were Amsterdam Schiphol, The Netherlands; and Boscombe Down in England. The tests were witnessed by representatives from the FAA, the European JAA and the Netherlands National Aerospace Laboratory.

Rockwell states that the first customer for its MMR is the U.S. military–probably the Rapid Deployment Force, which operates a number of portable MLS runway systems, primarily for tactical and battlefield use. Follow-on sales could include European airlines such as British Airways, which has specified Arinc-standard MMRs for the 87 Airbus A320 variants it has on order. Rockwell Collins, Honeywell and Thales of France each plan to offer MMR units.

While the FAA is planning on a future GPS WAAS and LAAS environment, with ILS backup, Europe is gradually moving toward a mix of ILS and MLS. Earlier this year, the French Civil Aviation Directorate ordered MLS equipment for all its Cat III runways, while the UK is expected shortly to award a contract for 27 Cat III MLS installations, including four systems at Heathrow, two each at Gatwick, Stansted and Manchester and single installations elsewhere. However, UK ILS installations will remain operational for non-MLS-equipped users. The British Royal Air Force is also assessing airborne and ground MLS requirements for its 67 domestic and overseas bases, as are other NATO air forces.