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Autopilot An Issue In Plane Crash

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The Associated Press

Published: February 16, 2009

Buffalo, N.Y. - As federal investigators searched the debris of Continental Connection Flight 3407, questions lingered over the use of the plane's autopilot system during icy conditions.

The downed plane, piloted by Lutz resident Marvin Renslow, crashed late Thursday as it made its way into Buffalo, killing all on board and one person on the ground.

On Sunday, a National Transportation Safety Board investigator said the plane was on autopilot until just before it went down, indicating that the pilot may have violated federal safety recommendations and the airline's own policy for flying in icy conditions. Both recommend switching to manual controls.

"You may be able in a manual mode to sense something sooner than the autopilot can sense it," said Steve Chealander, the NTSB investigator.

Despite those concerns, Chealander was careful not to criticize Renslow.

"Everything that should have been done was done, so we keep looking," Chealander said. "We keep looking, trying to find out why this happened."

In December, the NTSB issued a safety alert recommending that pilots in icy conditions turn off or limit the use of the autopilot to better feel changes in the handling qualities of the airplane.

But whether pilots should fly on autopilot or on manual controls in icy conditions is a matter of debate in aviation circles.
Federal Aviation Administration spokeswoman Laura Brown said it was too soon to say whether keeping Flight 3407 on autopilot contributed to the crash.

"We shouldn't make any conclusions at this time," she said.

Federal guidelines suggest a pilot should not engage the autopilot when flying through ice.

However, the FAA only advises pilots to disengage the autopilot when ice is accumulating. The guidance is not mandatory.

The agency considered making the guidance mandatory, but others in the aviation community argued against it, citing the capabilities of advanced planes, Brown said.

Some planes are certified to be flown on autopilot in icing conditions because doing so "may actually keep the aircraft at a steadier speed and altitude than a pilot could flying it manually," said Brown, though she did not know whether the 74-seat Q400 Bombardier Renslow flew was one of them.

If the ice is severe, Colgan Air, which operated Flight 3407 for Continental, requires pilots to shut off the autopilot. The company operates a fleet of 51 regional turboprops for Continental Connection, United Express and US Airways Express.

Flight 3407's crew noted "significant" ice buildup on the wings and windshield before it crashed. However, that doesn't correspond to any of the FAA's definitions of icing levels, the worst of which is "severe."

Severe is "the kind of icing you shouldn't be flying in," Chealander said at a news conference Sunday.

The icing conditions that beset Flight 3407 were not severe, he said.

The plane's de-icing system was turned on 11 minutes after it took off from Newark, N.J., and stayed on for the entire flight, Chealander said. Indicator lights showed that the system appeared to be working.

Chealander said the pilot was being "very conservative" by turning it on so soon.

Automatic safety devices returned the aircraft to manual control just before it fell from the sky, Chealander said.

During his Sunday briefing, Chealander described the flight's frantic last moments, which included a steep drop and rollercoaster-like pitching and rolling.

Information from the plane's flight data recorder indicates that the plane pitched up at an angle of 31 degrees in its final moments, then pitched down at 45 degrees, Chealander said.

The plane rolled to the left at 46 degrees, then snapped back to the right at 105 degrees - 15 degrees beyond vertical.

Radar data shows that Flight 3407 fell from 1,800 feet above sea level to 1,000 feet in five seconds, Chealander said. Passengers and crew would have experienced G-forces as much as twice as strong as those felt on the ground.

The plane crashed belly-first on top of a house Thursday night, killing all 49 people on board and one person on the ground.

By Sunday, authorities had recovered the remains of 15 people from the wreckage as crews raced to finish their work before a storm scheduled to hit later in the week.

Recovery efforts intensified after the arrival of additional federal workers, Erie County executive Chris Collins said. A storm forecast for Wednesday added to the urgency.

The storm could hamper recovery efforts, but "the investigation will continue, snow, rain or shine," said David Bissonette, the town's emergency coordinator.

Recovery crews could need as long as four days to remove the remains from the site. Chealander described the efforts as an "excavation."

"Keep in mind, there's an airplane that fell on top of a house, and they're now intermingled," he said.

DNA and dental records will be used to identify the remains, he said.

Once all the remains are recovered, the focus will turn to removing wreckage of the 74-seat aircraft from the neighborhood.

Tribune reporter Ray Reyes contributed to this report.

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