A lock-unlock lever on the doomed Virgin Galactic SpaceShipTwo was moved earlier than it should have been, the National Transportation Safety Board said Sunday night.
But the agency's acting chairman stressed it was unclear whether pilot error, mechanical problems or a host of other possibilities caused the spacecraft to disintegrate in the air.
"We are still a long way from finding a cause. We are months and months away," NTSB Acting Chairman Christopher Hart said.
And despite a debris field spanning 5 miles, investigators have found almost all the parts of the spacecraft needed for the investigation, Hart said.
The accident killed co-pilot Michael Tyner Alsbury, 39. A memorial fund has been set up for him.
Co-pilot alert and talking
The surviving co-pilot is "alert" and speaking, the company that partnered with Virgin on the test flight program said Sunday.
"Peter Siebold, the director of flight operations at Scaled Composites, was piloting SpaceShipTwo. He is alert and talking with his family and doctors," the company said in a statement.
"We remain focused on supporting the families of the two pilots and all of our employees, as well as the agencies investigating the accident."
NTSB investigators have yet to interview Siebold.
"We have not because doctors did not recommend we do an interview at this stage," Hart said.
Inflight breakup?
SpaceShipTwo disintegrated Friday, just two minutes after the space plane separated from the jet-powered aircraft that carried it aloft.
At the time, it was about 45,000 feet above, and about 20 miles northeast, of Mojave, California.
SpaceShipTwo helmed by experienced pilots when flight failed
While the NTSB hasn't determined what broke the test aircraft apart, "when wreckage is dispersed like that, it indicates the likelihood of in-flight breakup," Hart said.
A team of 13 to 15 investigators from the National Transportation Safety Board will be on site in the Mojave Desert for about a week. But analyzing the data from the test aircraft will take much longer.
(CNN)