SpaceShipTwo crash: Aerospace company failed to consider human error, NTSB says

On Tuesday, the National Transportation Safety Board (NTSB) said that a co-pilot's mistake was to blame in the October 2014 crash of Virgin Galactic's SpaceShipTwo, which killed the co-pilot and injured the pilot over the Mojave Desert, where the craft was being tested.

The NTSB added that Scaled Composites, the aerospace company that had built the SpaceShipTwo craft for Virgin Galactic and employed the two pilots, did not adequately consider the consequences of a human error such as the one that occurred and did not build fail-safes into the craft to compensate for that error.

The approximate cause of the crash was determined rather quickly—not two days after SpaceShipTwo appeared to explode in the sky 10 miles up, NTSB chairman Christopher Hart faulted an early deployment of “feathering mode,” which changes the direction of the craft's wings to slow it down for descent. As SpaceShipTwo was still in powered flight, the high-drag configuration could have caused the plane to break up.

Still, why this early deployment of the feathering system happened was subject to investigation. In a series of documents made public this morning, the NTSB suggested that the co-pilot, Michael Alsbury, engaged the first part of the two-part feathering system deployment too early, at Mach .8. (The system is generally deployed at Mach 1.4.) According to Wired, “aerodynamic load overpowered the actuators holding it in place, forcing it to open and causing SpaceShipTwo to break up in flight. Alsbury was killed, [pilot Peter] Siebold was badly injured but survived.”

NTSB reports describe the environment that led to the mistake: “According to Scaled Composites engineers and test pilots interviewed, the boost phase was a high workload phase of flight and duties were divided between the pilot and copilot. The copilot would unlock the feather at 1.4 Mach, with or without a callout, as indicated on the PF04 test card. Because of the workload, the speed was not crosschecked by the pilot flying.”

The NTSB also faulted Scaled Composites for failing to realize "that a single human error could result in a catastrophic hazard," according to the Los Angeles Times.

In a statement to the LA Times, Scaled Technologies said today, "Safety has always been a critical component of Scaled’s culture and, as the NTSB noted today, our pilots were experienced and well-trained. As part of our constant and continuing efforts to enhance our processes, we have already made changes in the wake of the accident to further enhance safety. We will continue to look for additional ways to do so."