4:51pm

Wed July 2, 2014
Drones

"Common problem" caused Air National Guard's drone to crash

An unmanned aircraft expert says a "not uncommon problem" caused an Air National Guard drone to smash into Lake Ontario last November.

The Air Force says multiple communication and navigation failures lead to the crash of an MQ-9 Reaper drone, piloted by the Syracuse-based 174th Attack Wing of the Air National Guard.

No one was hurt when the multi-ton aircraft plummeted into the lake 12 miles offshore, late last year.

(Read more on what caused the accident here.)

Agamemnon Crassidis is a mechanical engineering professor at the Rochester Institute of Technology and the academic director of upstate New York’s private drone research alliance, NUAIR. He reviewed the crash's accident report for The Innovation Trail.

GPS and internal navigation system failures on drones are their most common issue, he says. 

"I’m assuming what happened was, once it lost its location, it caused the drone to go into an emergency mode and it looks like those emergency system backup modes failed as well," he said.

The drone’s emergency backup autopilot mode is designed to steer away from populated areas on its way back to base, but Crassidis says with navigation systems down, some luck may have factored into the drone still being over water when it went down.

"In terms of the sensor not being able to locate the position, then essentially the unmanned aircraft system had no idea where it was," he said, "and we got lucky it didn’t crash into a populated area."

"I can't recover it," the pilot said as the MQ-9 went into a flat spin.
Credit U.S. Air Force accident report

The Air Force says a bad right turn while on autopilot sent the drone into an unrecoverable flat spin.

Crassidis says a drone under computer control is only as good a flyer as the sensors it has on board. 

"If that sensor fails, the autopilot has no chance," he said.

An Air Force review board released its report on the crash this week. It ruled there was no pilot error in the accident and the drone had passed a pre-flight inspection.

The MQ-9 had been in the air on a training mission upon take off from Fort Drum for about two hours when it encountered problems. It was just over 15 minutes from error to crash impact.