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Virgin Galactic SpaceShipTwo crackup verdict: PILOT ERROR

Feathercock unlock fingered as cause of Mach 1 midair breakup

By Kat Hall, 28 Jul 2015

The National Transport Safety Board has today given its verdict on last year's fatal Virgin Galactic crash, suggesting the cause of the tragic accident was human error and a lack of safety training.

The NTSB determined that the probable cause was manufacturer Scaled Composite's failure to mitigate against the human factor of unlocking the system early. They said this set the stage for the co-pilot’s error.

The NTSB heard there had not been an emphasis on the catastrophic effects of an early unlock, with no reference made to the consequence of doing so in the pilots’ handbooks.

Christopher Hart, chairman of NTSB, said: "Many of the safety issues we will hear are not from the novelty of space flight but human factors already known [in the aviation industry]."

​The NTSB met today to determine the probable cause of the October 31, 2014 in-flight breakup of a "SpaceShipTwo" rocketplane which occurred near Mojave, California.

Manufacturer Scaled Composites, the Federal Aviation Authority, Butler Parachutes and would-be operator Virgin Galactic were party to the investigation.

Outlining some of the findings, Lorenda Ward, investigator-in-charge, said there had been a lack of human factors guidance for commercial space operators.

She said there had been missed opportunities by the FAA, including limited familiarity with commercial space operators and emergency response scenarios.

SpaceShipTwo broke up during a rocket-powered test flight last year seriously injuring the pilot and killing the co-pilot, Michael Alsbury.

Investigators took into account the safety design of the rocket, the training pilots received and whether mechanical problems could be to blame.

NTSB officials have already revealed that the co-pilot prematurely unlocked the "shuttlecock" tail booms, which had been intended to slow the craft's descent into the atmosphere at a later stage in the flight.

According to the NTSB, Alsbury manually unlocked the system around nine seconds after motor ignition. Subsequently the tail booms apparently moved themselves into the feather position, provoking a catastrophic structural failure at "just above approximately Mach 1.0".

The reason Alsbury unlocked the system early may have been because he did not want to risk aborting the flight, as the system must be unlocked prior to reaching Mach 1.8.

After the accident Scaled grounded its fleet and conducted a review, said Ward. It looked at parachute training and improved that, and identified that it did not have human factor expertise and has added that to its procedures.

Virgin Galactic has added an inhibitor so its feather locks cannot be unlocked in certain conditions.

Virgin Galactic is undeterred by the accident and will be carrying aloft its first paying customers "within 18 months to two years", according to chief executive George Whitesides. ®

Bootnotes

Alsbury had a relatively unusual background for a test pilot. The mainstream career path even for civilian test pilots typically involves military service - most commonly as a fast-jet pilot, certainly for someone testing something supersonic like SpaceShipTwo - and graduation from a dedicated military test-pilot school followed by military and civilian test flying. The relatively rare civilian test pilots will still normally attend a test-pilot school - for instance the mainly-military Empire Test Pilot School in Britain trains some civilians. Such a career will involve work within various different organisations flying many different types of aircraft.

Alsbury by contrast had reportedly joined Scaled Composites in 2001 aged 26, with just 200 flying hours logged. All his subsequent flight experience was as a Scaled flight-engineer and pilot.

SpaceShipTwo, like the Ansari X-Prize winning SpaceShipOne upon which it is based, is routinely described as a "spacecraft" and technically it is, as it can fly high enough to be said to have reached space. Neither craft is capable of reaching orbit, however, and SpaceShipTwo offers no "space" applications beyond zero-G joyrides (which can be more effectively achieved in a normal jet aircraft such as the NASA "Vomit Comet" used for astronaut training).

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