NASA/FAA Flight-Test Investigation of Helicopter Microwave Landing System Approaches

The first of a series of joint NASA/FAA helicopter Microwave Landing System (MLS) flight-test investigations was conducted during the spring and summer of 1979 to provide the FAA statistical data with which to establish Terminal Instrument Procedures (TERPS) criteria and to provide NASA a performance data base for development of advanced MLS guidance concepts. Specific test objectives were to determine MLS airspace requirements, weather minima, and pilot acceptability. Fourteen pilots from various elements of the helicopter community flew 140 manual (without stability augmentation) dual-pilot simulated instrument approaches in a Bell UH-1H helicopter, The angle-only (glideslope and localizer) approaches were made using raw data without a flight director or Distance Measuring Equipment (DME). Missed approaches and landings were conducted for 3°, 6°, and 9° glideslope approaches on runway centerline to decision heights of 50, 100, and 150 ft, respectively. A 3° glideslope approach on a 20° lateral offset to a decision height of 200 ft was also flown. This paper presents the results of the flight-test investigation.