Virgin Galactic: 'Single human error' led to catastrophic crash, NTSB says

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Source: Los Angeles Times

Federal safety officials Tuesday blamed the builder of Virgin Galactic's SpaceShipTwo for failing to anticipate the copilot error that caused the aircraft's disintegration during a test flight nine months ago.

The staff of the National Transportation Safety Board, at a meeting in Washington, initially listed the probable cause as copilot Michael Alsbury's premature unlocking of the space plane's "feather system," or movable tail.

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But after a discussion, the NTSB staff revised the probable cause, placing most of the blame on Scaled Composites, which had designed and built SpaceShipTwo for Virgin Galactic.

The NTSB blamed Scaled for failing to consider "that a single human error could result in a catastrophic hazard."

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Read more: http://www.latimes.com/business/la-fi-ntsb-virgin-20150727-story.html

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1. NTSB: Scaled's Failure To Protect Against Human Error Led to Loss of SpaceShipTwo

http://www.spacepolicyonline.com/news/ntsb-scaleds-failure-to-protect-against-human-error-led-to-loss-of-spaceshiptwo

NTSB: Scaled's Failure To Protect Against Human Error Led to Loss of SpaceShipTwo

Marcia S. Smith
Posted: 28-Jul-2015
Updated: 28-Jul-2015 03:06 PM

The National Transportation Safety Board (NTSB) voted today to adopt its final report on the October 31, 2014 SpaceShipTwo (SS2) accident that killed one of the spaceplane's two pilots. The Board agreed to 17 findings and 10 recommendations, along with a statement of probable cause that focused on the failure of Scaled Composites to "consider and protect against" the possibility that a single human error could doom the vehicle and its crew.

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It was immediately evident from telemetry and cockpit video that Alsbury had prematurely moved one of two levers that activate a feathering system intended to slow the spaceplane during descent, creating aerodynamic instability that tore the plane apart. Why he did so and why the feathering system deployed even though the second lever was not activated were among the subjects of the investigation.

The findings and recommendations span a wide range of concerns about government and private sector actions, many of which were leveled at the FAA's Office of Commercial Space Transportation (AST), but the statement of probable cause is aimed at Scaled, which built SS2 and was in charge of the test flight.

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The National Transportation Safety Board determines that the probable cause of this accident was Scaled Composites' failure to consider and protect against the possibility that a single human error could result in a catastrophic hazard to the SpaceShipTwo vehicle. This failure set the stage for the copilot’s premature unlocking of the feather system as a result of time pressure and vibration and loads that he had not recently experienced, which led to uncommanded feather extension and the subsequent aerodynamic overload and in-flight break up of the vehicle.

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One focus of the investigation was the training the pilots received including human factors and the information formally conveyed to them by Scaled about the dangers of premature deployment of the feathering system. The NTSB found that the copilot (Alsbury) was experiencing high workload as a result of recalling tasks from memory while performing under time pressure and with vibration and loads that he had not recently experienced, which increased the possibility for errors. NTSB found that Scaled "did not ensure that pilots correctly understood the risks of unlocking the feather early" and missed opportunities to mitigate against the consequences of human error in its design.

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