Investigators say the violent movements that killed a Maryland woman aboard a private jet this month were multiple times the pull of gravity and were not caused by the weather.

The National Transportation Safety Board said the aircraft experienced a force about four times the pull of gravity when the pilots disabled a setting that is used to stabilize the aircraft. The pilots were in the process of resolving warning messages from the aircraft.

“As soon as the switch position was moved, the airplane abruptly pitched up,” the preliminary report said.

One of the pilots “immediately with both hands regained control of the airplane in what he estimated to be a few seconds after the airplane’s pitch oscillated up and down.”

The plane pitched up and down like a rollercoaster several times: First 3.8Gs upward, then 2.3Gs downward, followed by 4.2Gs upward.

The Bombardier CL30 jet departed from Dillant-Hopkins Airport in Keene, New Hampshire, on March 3 and was headed to Leesburg Executive Airport in Virginia when it was diverted to Bradley International Airport in Windsor Locks, Connecticut, after “encountering severe turbulence,” the Federal Aviation Administration wrote in a statement to CNN at the time.

The pilots had received multiple alerts from the aircraft prior to the incident, and even aborted their first takeoff attempt because of an issue with the aircraft. They discovered a protective cover used when the aircraft is parked was left on the plane, the report said.

After restarting the plane, they received additional alerts from the aircraft but proceeded with the takeoff and flight because the alerts did not meet the threshold for grounding.

At the time of the incident, the pilots were attempting to resolve the issues by using a checklist for a failure of the primary stabilizer trim, the report said.