NTSB: Pilot Error a Major Factor in the Loss of SpaceShipTwo

Only two days in to an investigation which was expected to take up to a year,  the National Safety Transportation Board team looking in to Friday’s Virgin Galactic crash at the Mojave spaceport has made a surprising discovery, one which overturns almost all of the early assumptions about what led to the disaster. Speaking at press conference Sunday evening, the NTSB’s Christopher Hart revealed that “uncontrolled feathering” led to the mid air break-up of SpaceShipTwo. Ordinarily, initiating the feathering maneuver, which is used to increase drag and slow the vehicle as it begins its descent is a two step process which begins with unlocking the feather brake, followed by engaging a separate control which places the twin boom fins into the “feather” position.

Based on telemetry, which includes video feed from the cockpit, investigators can conclusively say that Scaled Composites co-pilot Michael Alsbury, who died in the crash, prematurely unlocked the feather brake.  Instead of occurring at Mach 1.4 as planned, the action took place at Mach 1.0. Seconds later, and without the second control being actively engaged, feathering fins extended, and the aircraft broke up. In short, pilot error was a major contributor to Friday’s accident.

Investigators have stressed that this discovery is not being labelled as the cause of the accident, and that the ongoing investigation will still require many months of work, with the team taking a hard look at training and the overall safety culture which has been called into question.  Nevertheless, the news appears to buttress Richard Branson’s Saturday allegations that some elements were reaching “irresponsible” conclusions in the absence of facts. While no less saddened by the outcome, the Virgin founder is likely taking some comfort in the fact that the NTSB team also determined that there was no burn-though of the nylon based hybrid rocket, and in fact the entire propulsion system appeared to have worked exactly as designed. It should be pointed out however, that even if those initial conclusions are validated, it does not necessarily change the basic facts around what has been a problematic development path for SpaceShipTwo, and in particular its hybrid motor. Questions will remain, but a path forward may be coming into view.

Although Virgin is still facing the loss of its first spaceplane, an ongoing investigation which will be asking tough questions and a likely multiyear setback to its operations, the sun which rises over the California desert today may offer a ray of encouragement which was nowhere to be found in the immediate aftermath of the accident.

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