With questions surrounding what happened when the pilot attempted to pull his plane’s nose up for takeoff, investigators remained at Hanscom Field searching for clues in the private jet crash that killed seven people.
Efforts continued on Wednesday to document the wreck of the plane and remove it from the crash site in Bedford, Peter Knudson, a spokesman for the National Transportation Safety Board, said in a telephone interview.
The investigators are expected to continue working at the scene through the end of the week, he said. Officials have said that the plane’s flight data recorder and cockpit voice recorder have been recovered and sent to the agency’s Washington laboratory for analysis.
A preliminary accident report will probably be issued next week, Knudson said. He offered no further details.
“The course of the investigation is going to look at everything: the pilot, the environment, the machine itself,” he said.
Philanthropist Lewis Katz, co-owner of the Philadelphia Inquirer, was remembered at a service Wednesday in that city. Katz died in the crash Saturday night, along with three guests and three crew members.
Aircraft specialists said that a key question for investigators is what happened when the pilot sought to pull the nose of the jet up and take to the sky.
On Tuesday, Luke Schiada, NTSB’s lead investigator at the scene, described a normal takeoff up to the point that the copilot called out to the pilot that it was time to “rotate,” or pull the nose up.
“After the rotate callout, the [cockpit voice recorder] captured comments concerning aircraft control,” Schiada said at a briefing for reporters at the airport.
He would not elaborate on what the “comments concerning aircraft control” were. But he said the airplane never left the ground and began decelerating as thrust reversers were engaged and brake pressures rose.
The rise of brake pressures indicated that the pilots were putting on the brakes, said R. John Hansman, a professor of aeronautics and astronautics at MIT and an experienced pilot. Thrust reversers, which direct engine thrust to the front of a jet plane, are also used to slow down planes.
The moment of rotation was “the point at which the nose was supposed to come up,” Hansman said. “It sounds like there was some flight control problem. . . . They didn’t think the airplane could fly and it was preferable to go off the end of the runway.”
If the pilots could not pull the nose up, they might have been forced to decide, “I can’t fly, so I might as well try to hit something on the ground” going as slowly as possible, Bruce Landsberg, president of the Aircraft Owners and Pilots Association Foundation in Frederick, Md., said Tuesday.
The plane continued off the end of the runway, and came to rest at the bottom of a gully, where it burst into flames. The Gulfstream IV jet reached a speed of 190 miles per hour before slowing down and crashing, air crash investigators said.
• Pilots may have tried to stop plane
• Data recorders found in rubble of Hanscom crash
• Photos: Plane crash at Hanscom Field
• Audio: 911 calls made after the crash
• Lewis Katz remembered at memorial service
Martin Fincuane can be reached at martin.finucane@