WASHINGTON (AP) - The National Transportation Safety Board concluded Tuesday that the developer of a commercial spacecraft that broke apart over the Mojave Desert last year failed to protect against the possibility of human error, specifically the co-pilot's premature unlocking of a braking system that triggered the in-flight breakup of the vehicle.
In its recommendation, the board took pains to make clear Scaled Composites, an aerospace company that has partnered with Virgin Galactic to develop the spacecraft, should have had systems in place to overcome the co-pilot's mistake.
NTSB Chairman Christopher Hart said he didn't believe the company took shortcuts that compromised the spacecraft's safety. Rather, he said, it didn't consider the crew would make such a mistake.
"The assumption was these highly trained test pilots would not make mistakes in those areas, but truth be told, humans are humans," Hart said after the hearing's conclusion. "And even the best-trained human on their best day can make mistakes."
At the onset of the hearing, investigators told the board that the co-pilot unlocked the braking system and the resulting forces caused the brakes to actually be applied. The "aerodynamic overload" caused the ship to break-up, though Hart said protections have been put in place since.
"We are confident that the steps they have taken would prevent this accident from happening," Hart said.
The spaceship broke apart over the Mojave Desert during a test flight 10 months ago. The accident killed the co-pilot and seriously injured the pilot.
In determining the probable cause of the accident, board members were focused on how well officials prepared for the worst. Scaled Composites developed the craft for Virgin Galactic, and NTSB member Robert Sumwalt said the company "put all their eggs in the basket of the pilots doing it correctly."
"My point is that a single-point human failure has to be anticipated," Sumwalt said. "The system has to be designed to compensate for the error."