US authorities are investigating what caused a Boeing A160T Hummingbird unmanned aircraft system to crash at Victorville airport in California on 28 July.

The Pratt & Whitney PW207D-powered long-endurance helicopter auto-rotated to the ground and rolled on to its side during the incident, which happened within airport traffic airspace and about 4.4nm (2.4km) away from the planned landing point, Boeing says. The company declines to release further details pending the investigation.

Designated A007, the crashed aircraft is owned by the Army Aviation Applied Technology Directorate, which is using the Hummingbird for envelope expansion tests.

It was not immediately clear whether the accident could affect other A160T flights, but the US Special Operations Command says it is checking on the status of its eight-strong fleet. Two of its UAS were expected to be deployed to South America.

Boeing's two versions of the A160 have encountered several mishaps while in flight-testing in the past decade. The gas-powered version crashed three times in 36 flights, while a turbine-powered A160T A008 crashed in December 2007. The latter incident was blamed on a software error.

Source: Flight International