July 23, 2014
The remotely piloted Air National Guard drone that crashed last November into Lake Ontario was flying with equipment that likely couldn’t function properly in cold weather.
Besides some clouds on November 12th last year, crew members recalled to accident investigators that it was a nice day for flying. But it was a cold, late fall day; just below freezing on the ground at Fort Drum, where the Air National Guard launches its remotely piloted aircraft, for training missions over upstate New York.
The MQ-9 Reaper had been in the air for nearly two hours, under the control of 174th Attack Wing pilots at Hancock Airfield in Syracuse. Then it began to experience problems.
“It was kind of a perfect storm how this thing happened.”
Air Force Colonel Dana Hessheimer wrote the Accident Investigation Board report into the crash. It was finished earlier this month. The nearly 700 page report was obtained by WRVO through a Freedom of Information request.
In it, the Air Force cites multiple navigation system failures for the crash. Two of the three navigation systems on board, known as EGIs, failed and the pilots lost contact with the aircraft. That sent it into an emergency, pre-programmed flight: flying circles far over Lake Ontario.
A launch and recovery crew at Fort Drum then tried to regain control of the aircraft. Hessheimer says they did. But just as the pilot entered a right turn, he says the plane’s autopilot “zeroed out,” or stopped functioning.
“If he had waited another 20 seconds, it would of probably came back and then it would of flown back just fine,” says Hessheimer.
Instead, the Reaper inverted and ended up in a flat spin.
“Kind of like, if you remember Top Gun, when Goose died? That’s kind of like what the airplane was doing."
It plunged into Lake Ontario, falling at a rate of more than 80 feet per second. A few pieces of wreckage washed up on shore, but most of the plane was never found.
MQ-9’s carry three navigation systems - in case one fails. But this wasn’t the first time that particular aircraft had navigation problems for the 174th. Twice in the weeks before the crash, maintenance crews removed and replaced EGIs.
“Yeah, maybe a little bit of a red flag for it…”
Hessheimer writes in the summary of his report that he also considered if air temperature played a role in the crash. But he writes there was not enough evidence to say it was a substantial factor.
However, during a conference call, reporters pressed Colonel Hessheimer on the issue.
“But can you say, can you rule out that temperature played any role in this?”
“No, I can’t rule it out.”
He wouldn’t elaborate, other than to say it was a software problem.
At 18,000 feet, where the drone was flying that November afternoon, the air temperature hovered -34 degrees Fahrenheit.
“Pretty cold. I would think that’s pretty darn cold.”
Agamemnon Crasssidis is an engineering professor at the Rochester Institute of Technology. And he’s the academic leader for upstate New York’s private drone research consortium, NUAIR. He reviewed the accident report for WRVO.
He says aircraft must be able to adjust to air temperatures, or they won’t perform properly.
“Everything’s temperature dependent, because that changes the density of the air around it,” says Crassidis.
Crassidis says cold weather could have impacted the navigation software in two ways. One, it could have slowed the system’s ability to run the processors fast enough to operate the software. Or, the EGI couldn’t properly compute air temperature information in order to calibrate the aircraft’s movements.
The MQ-9 is manufactured by General Atomics. The company tested the two navigation systems previously pulled from the drone that crashed and exposed them to cold weather flight conditions. One of them failed “multiple times.”
General Atomics says it doesn’t comment on accidents. The Air Force also acknowledges in the accident report those versions of the Reaper’s navigation system can fail at cold temperatures.
Honeywell Aeronautics, the maker of the navigation systems, declined to answer specific questions. However, spokesman Scott Sayres says they provided a software upgrade for the navigation systems in June of 2012, more than a year before the 174th’s Reaper crashed.
“So we provide the upgrade to General Atomics. If it was implemented or what they did with it, you’d need to talk to G.A. about that,” says Sayres.
Colonel Hessheimer, with the Air Force, says the problem was identified within days of the accident and the Air Force sent out a world-wide recall for all MQ-9s.
“It’s kind of like G.M. lately," says Hessheimer, "I guess they’re in the news. They do a recall. They did the same thing in the Air Force. It’s called an alert bulletin."
It ordered different versions of the software be installed. Both the Air Force and General Atomics say running a different version of the software has prevented further cold-weather flight problems since the 174th‘s MQ-9 fell out of the sky one afternoon last November.