HARTFORD, Conn. – A business jet flying over New England earlier this month violently rocketed up and then down, fatally injuring a passenger, after pilots responded to automated cockpit warnings and disabled a system that helps keep the plane stable, U.S. transportation investigators reported Friday.
The National Transportation Safety Board, in its preliminary report, did not reach conclusions about the root cause of the March 3 fatal accident, but described a series of things that went wrong before and after the plane spun out of control.
Faced with several warnings in the Bombardier jet’s cockpit, pilots followed a checklist and turned off a switch that “trimmed” or adjusted the stabilizer on the plane’s tail, the report said.
The plane’s nose then swung upward, subjecting the people inside to forces about four times the force of gravity, then pointed downward before pivoting back up before pilots could regain control, the report said.
Pilots told investigators they had not experienced turbulence, as the NTSB said in an initial assessment the day after the incident.
The trim system on the Bombardier Challenger 300 twin-engine jet was the subject last year of a Federal Aviation Administration mandate that pilots perform additional pre-flight safety checks.
Bombardier did not immediately comment on the contents of the report, saying in a statement that it was “carefully studying” it. In an earlier statement, the Canadian manufacturer said it stands behind its Challenger 300 jets and their airworthiness.
“We will continue to fully support all authorities and provide assistance where necessary,” the company said on Friday.
The two pilots and three passengers were traveling from Keene, New Hampshire, to Leesburg, Virginia, before diverting to Bradley International Airport in Connecticut. A passenger, Dana Hyde, 55, of Cabin John, Maryland, was taken to a hospital where she died of blunt force injuries.
Hyde held government positions during the Clinton and Obama administrations and was counsel to the 9/11 Commission, formally known as the National Commission on Terrorist Attacks Upon the United States.
It was unclear whether Hyde was strapped into her seat or upright in the cabin of the Conexon aircraft, based in Kansas City, Missouri. Her husband and their son, as well as the pilot and co-pilot, were not injured in the incident, the report said.
A representative of Conexon, a company specializing in rural internet, declined to comment Friday.
The report indicated that the pilots aborted their first takeoff because no one had removed a plastic cover from one of the outer tubes that determine airspeed, and that they took off with a rudder limiter error message on.
Another warning indicated a failed autopilot stabilizer trim. The plane rocketed abruptly as the pilots moved the stabilizer trim switch from primary to off as they worked through procedures on a checklist, the report said.
The plane oscillated violently up and down and the “stick pusher” activated, the report said, meaning the onboard computer thought the plane was in danger of stalling too aerodynamically.
John Cox, a former airline pilot turned safety consultant, said there were “certainly issues” with the pilots’ pre-flight actions, but he said they responded correctly when they followed the checklist for responding to trim errors.
The cockpit crew consisted of two experienced pilots with 5,000 and 8,000 flight hours and had the necessary qualifications to fly for an airline. But both were relatively new to the aircraft model and earned their ratings last October.
The FAA issued its guidance on Bombardier Challenger 300 jets last year after multiple instances where the horizontal stabilizer on the planes caused the plane’s nose to drop after the pilot attempted to climb the plane.