LOS ANGELES (CBSLA.com) — The National Transportation Safety Board on Tuesday confirmed co-pilot error as the cause of the deadly failure of Virgin Galactic’s SpaceShipTwo spacecraft over the Mojave Desert in October.
The confirmation comes as the result of a lengthy investigation, which also identified the plane’s builders’ failure to anticipate the potential of such a mistake with a percentage of the responsibility.
The spacecraft suffered catastrophic failure and broke apart during a powered flight test, killing co-pilot Michael Alsbury and critically injuring pilot Peter Siebold. The NTSB stated in a conference on Tuesday that Albury was found to have unlocked the spacecraft’s feathering system shortly after the SpaceShipTwo had separated from its mother-ship, WhiteKnightTwo, and had fired its hybrid rocket engine.
In the feathering procedure, a pilot will unlock then deploy the stabilizers. These rotate two tail booms upward to create drag and slow the spacecraft as it aligns into a “belly-up” position before re-entry into the atmosphere.
The procedure was designed to be used as a form of descent only. In the case of SS2’s crash, it appears Alsbury unlocked the feathers early, as the spacecraft was still accelerating. NTSB says the breakup occurred after the craft passed Mach 1 — the speed of sound.
The report, read by NTSB Chairman Christopher Hart, indicates the unlocking of the feathering system was activated too early. This caused the plane to encounter an excessive amount of air resistance and ultimately leading to its disintegration.
The board also suggested that Scaled Composites, the development company that built the spacecraft, took part in the responsibility of the crash, due to its “failure to consider and protect against the possibility that a single human error could result in a catastrophic hazard to the SpaceShipTwo vehicle.”
The feathering system had been used during 10 prior test flights, after initial powered test flights began in April of 2013.
The tragedy marked the first fatality on a spacecraft during flight since the Columbia failed during re-entry after the STS-107 mission in 2003, in which seven crew members were killed.