Teledyne Ryan Aeronautical (TRA) is investigating a hydraulic failure which marred the otherwise successful third flight of the Global Hawk unmanned air vehicle (UAV).
The aircraft lost hydraulic pressure on approach to the runway at Edwards AFB, California, after the 5h 22min flight on 30 May. The landing gear was lowered using the back-up blow-down system and the UAV executed a normal touchdown, but the back-up pneumatic braking system could not stop the vehicle, which left the runway at low speed having completed its landing roll-out. Only superficial damage was sustained, TRA says. The aircraft is to make its fourth flight as scheduled in early July.
The Global Hawk reached 51,200ft (15,600m) on its third flight, covering a 4,000km (2,200nm) flightpath at speeds of up to 360kt (670km/h). A total of 16 flights is planned, using two air vehicles. The second Global Hawk will be shipped later this month.
Funding has been provided for an initial five air vehicles and Congressional committees have added funds to the 1999 budget to build more Global Hawks to bridge the gap between the demonstration phase and production.
Source: Flight International
