‘Event’ Made Plane Roll, Crash, Investigator Says

Everything appeared normal on a Comair commuter flight before an unexplained “event” that started a roll and nose dive into a snowy field that killed all 29 people aboard, a federal investigator said Saturday.

Though the National Transportation Safety Board has yet to complete its analysis of the plane’s “black boxes,” its investigation so far has found that something unusual happened as the plane approached Detroit.

“Approximately one minute after leveling off at 4,000 feet, an event took place and normal operations ceased and the airplane crashed shortly thereafter,” said NTSB member John Hammerschmidt.

One witness told investigators that the plane had made several of what Hammerschmidt described as “axle rolls.” Two others said the plane’s wings had been rocking shortly before the crash.

“They all indicated that the airplane stabilized, then the nose of the aircraft abruptly pitched and descended vertically to the ground.”

The twin-engine turboprop Embraer 120 that flew out of Cincinnati plummeted into the field Thursday about 18 miles short of its destination of Detroit Metropolitan Airport.

Hammerschmidt said the plane’s pilot and co-pilot reported nothing unusual during the flight, and air traffic controllers said nothing seemed amiss.

Also, the captain and first officer who had flown the plane on four legs before the crash “both reported that the plane flew quite satisfactorily,” he said.

When the plane crashed, there had been two warnings about “moderate, occasional, severe turbulence,” Hammerschmidt said. Winds were light and visibility was 1 to 3 miles.

A DC-3 pilot in the area made a report shortly after the crash of moderate, mixed icing at 5,000 feet, he said.

“What’s significant about that is that the DC-3 was about 25 miles southwest of Detroit Metropolitan Airport. But that’s just another piece of information to plug into the equation,” Hammerschmidt said.

Icing disrupts airflow over the wings and can cause planes to stall or roll.

A preliminary investigation at the accident site showed that both engines appeared to have been rotating when the plane hit the ground, and all eight propeller blades appear to have been rotating on impact, Hammerschmidt said.