Operator error caused the 25 April crash of the US Customs and Border Patrol’s first General Atomics Predator B unmanned air vehicle, according to preliminary information from the US National Transportation Safety Board (NTSB).
A failure to follow procedure when transferring control between operator stations caused the UAV’s engine to shut down, and the Predator crashed near Nogales, Arizona.
The mistake occurred when the pilot’s operator console “locked up”, and he switched control to the payload operator’s console. The checklist requires the pilot to match the control positions on the new console to those on the station that had been controlling the UAV. The pilot failed to do this, says the NTSB.
The stop/feather control on the second console was in the fuel cut-off position when the switchover occurred. “As a result, the fuel was cut off to the UAV when control was transferred,” says the NTSB.
Unaware the Predator’s engine had been shut down during the switchover, the pilot “noticed the UAV was not maintaining altitude, but did not know why”, says the NTSB. He decided to shut down the ground control station to force the UAV to enter its autonomous lost-link procedure, but with no power the Predator continued descending until it hit the ground and was destroyed.