By Graham Warwick in Washington DC
US Customs and Border Patrol (CPB) is trying to determine why the General Atomics Aeronautical Systems MQ-9 Predator B unmanned air vehicle that crashed near the Mexican border on 24 April did not come down where it was programmed to if communications were lost and could not be re-established.
The ground station at Ft Huachuca, Arizona lost contact with the UAV at 02:50, when the vehicle was about 8.5h into a 10-12h mission patrolling the US-Mexican border at between 12,000ft (3,600m) and 15,000ft. The wreckage was found about 16km (10 miles) north of Nogales, Arizona at about 06:20.
When the communications link was lost, the Predator was supposed to fly autonomously via emergency waypoints to a safe loiter area closer to base. If, after 30min, it was unable to re-establish communications, the vehicle was then programmed to set down in a pre-determined area.
Instead, the wreckage was found close to where the link was lost, suggesting the UAV crashed soon after losing communications. There was no indication of problems with the vehicle before the link was lost, says the CBP. The lost-link recovery function is implemented in the Predator’s triple-redundant flight-control computer.
The UAV entered service with the CBP in September, and had logged 900 flight hours, operating in civil airspace but protected by a temporary flight restriction in effect along the border from 17:00 to 07:00.