The Global Hawk unmanned aerial reconnaissance system completed its first night mission on 17/18 September, despite the inflight failure of one of its two integrated mission management computers (IMMCs).

The aircraft left Edwards AFB, California, at 19:34 Pacific Time and suffered the IMMC failure at about 01:00. Teledyne Ryan Aeronautical, prime contractor for the Global Hawk, says the "-unaffected IMMC seamlessly took complete control of the aircraft when the malfunction occurred. It then automatically executed a preprogrammed contingency flightplan, safely returning the Global Hawk to Edwards." During the 6h flight, the aircraft achieved a maximum altitude of 58,800ft (17,950m).

The Global Hawk returned to Edwards at 01:46, landing autonomously using differential global positioning system data that guided it to touchdown and roll out close to the runway centreline. Teledyne Ryan says that programme engineers are "-now working to determine the cause of the malfunction".

The company says the IMMC incident proved the effectiveness of the aircraft's redundant controls and its autonomous contingency flightplan system.

The night flight, which was the fifth mission, was intended to be a much longer sortie to evaluate the performance of the environmental control system during a cold night flight. The Global Hawk was therefore loaded with its maximum capacity of 6,350kg (14,107lb) of fuel at take-off and landed safely, despite the heavy fuel load.

Source: Flight International