by HARTFORD, Conn. — A business jet flying over New England earlier this month tilted violently up and then down, fatally injuring a passenger, after pilots responding to automatic cockpit warnings turned off a system that helps to keep the aircraft stable, US transportation investigators reported Friday.
The National Transportation Safety Board did not reach any conclusions in its preliminary report about the root cause of the deadly crash on March 3, but it did describe a number of things that went wrong before and after the plane went out of control.
Faced with several alerts in the cockpit of the Bombardier plane, the pilots followed a checklist and turned off a switch that “trims” or adjusts the stabilizer in the plane’s tail, according to the report.
The plane’s nose then rose upward, subjecting the people inside to forces roughly four times the force of gravity, then pointed downward before swinging upward again before the pilots could regain control. control, according to the report.
The pilots told investigators they found no turbulence, as the NTSB had said in an initial assessment the day after the incident.
The trim system on the Bombardier Challenger 300 twin-engine plane was the subject of a Federal Aviation Administration mandate last year for pilots to perform additional safety checks before flights.
Bombardier did not directly respond to the content of the report, saying in a statement that it was “studying it carefully.” In an earlier statement, the Canadian manufacturer said it stood behind its Challenger 300 planes and their airworthiness.
“We will continue to support and provide full assistance to all authorities as needed,” 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. One passenger, Dana Hyde, 55, of Cabin John, Maryland, was taken to a hospital where she died of blunt force injuries.
Hyde held government posts during the Clinton and Obama administrations and was a lawyer for the 9/11 Commission, formally known as the National Commission on Terrorist Attacks in the United States.
It was not clear if Hyde was buckled into her seat, or circling, in the cabin of the plane owned by Kansas City, Missouri-based Conexon. Her husband and her son, along with the pilot and co-pilot, were not injured in the incident, according to the report.
A representative for Conexon, a company specializing in rural internet, declined to comment Friday.
The report stated that the pilots aborted their initial takeoff because no one removed a plastic cover from one of the outer tubes that determine airspeed, and they took off with a rudder limiter failure alert activated.
Another warning indicated a fault in the autopilot’s stabilizer trim. The plane pitched steeply upward when the pilots moved the primary stabilizer trim switch to off while working through procedures on a checklist, according to the report.
The plane rocked violently up and down and the “stick pusher” activated, according to the report, meaning the onboard computer thought the plane was in danger of stalling.
John Cox, a former airline pilot and now a safety consultant, said there are “definitely problems” with the pilots’ pre-flight actions, but said they reacted correctly when they followed the checklist for responding to a trim failure. .
The flight crew consisted of two experienced pilots with 5,000 and 8,000 hours of flight time, and had the necessary qualifications to fly for an airline. But both were relatively new to the model plane and got their qualifications last October.
The FAA issued its directive on Bombardier Challenger 300 aircraft last year after multiple instances in which the aircraft’s horizontal stabilizer caused the plane’s nose to pitch down after the pilot tried to get the aircraft to climb.
