A human-factors expert will join the investigation of the fatal crash of Virgin Galactic's passenger spacecraft to study why the co-pilot prematurely unlocked a pivoting tail section of the ship during a test flight, a top safety official said on Monday.
The untimely engagement of the tail mechanism, designed to slow the vehicle's descent into the atmosphere from space, and the possibility that pilot error was to blame, were disclosed by the National Transportation Safety Board (NTSB) late on Sunday and have emerged as a main thrust of the inquiry into Friday's crash.
"We know already from having the lever move from lock to unlock that we need to get a human-factors person in here," said NTSB Chairman Christopher Hart. "The question then is why did that happen when it happened?"
Investigators have yet to determine whether releasing the tail mechanism too early caused or contributed to the crash of the space plane near the Mojave Air and Space Port, about 95 miles (150 km) north of Los Angeles, Hart said in an interview.