Abstract:
A flight test was conducted by the U.S. Army Degraded Visual Environment Mitigation (DVE-M) program in an EH-60L helicopter at Yuma Proving Ground. The pilots used an integrated combination of multispectral terrain/obstacle sensors, pilot cueing, and improved flight control to accomplish 64 landings and 55 precision hover maneuvers in heavy brownout conditions. Approach guidance was provided as a target horizontal speed and target vertical speed on the pilot's displays. Sensor-driven guidance was developed but not used due to the large number of false-positive returns. All 64 landings were safe. Landings were all within 22 ft (mean 5.8 ft) of the target landing point as measured with the EGI inertial sensor. Lateral speed at touchdown was always within 1.5 knots (mean 0.3 knots). Vertical speed at touchdown was always within 180 ft/min (mean 97 ft/min). Six go-around maneuvers due to pilot performance were conducted safely by the pilots using the cueing. Pilots reported that they had little spare capacity to interpret the sensor image since they were focused on following the approach guidance cues on the display. Hover and landing maneuvers were compared with and without coupled collective. Pilots reported a major reduction in workload with coupled collective as measured on the Bedford scale for both landing and hover. With coupled collective hover position keeping improved. Heading hold was available and used on all maneuvers. Aural cueing was rated highly as implemented in this test. Tactile (vibrating seat, waist belt, and shoulder strap) was rated poor as implemented on this test on the subjective usability questionnaire. In particular, pilots requested that only one axis be active at a time, and that tolerances be loosened.