Sunday, November 9, 2014

Report: Pilot Error Responsible for SpaceShipTwo Loss

A Wall Street Journal report claims that the SpaceShipTwo VSS Enterprise co-pilot unlocked the feathered wing deploy mechanism without being commanded to do so by the pilot.

(If the WSJ pay wall blocks you from seeing the entire article, use Google to search the headline, “Commander of Virgin Galactic Craft Didn’t Order Tail Surfaces Unlocked Before Crash.” That usually circumvents the pay wall.)

The co-pilot of the Virgin Galactic LLC rocket ship that crashed during a test flight last week unlocked movable tail surfaces earlier in the flight than normal without being instructed to do so by the craft’s commander, according to people familiar with the investigation ...

The latest information buttresses the theory that [Michael] Alsbury acted unilaterally to unlock the tail surfaces, contrary to normal timing and procedures the two aviators discussed during a briefing before the accident. A second lever is used to actually deploy the feathering system, which is designed to slow the craft as it returns from space and to set it up for a safe glide back to Earth.

The article reports that pilot Peter Siebold still hastn't been interviewed by the National Transportation Safety Board investigators due to his physical condition. According to the article, Mr. Siebold remains on heavy painkillers, and the NTSB wants to wait until his medications are reduced.

Despite early Internet rumors blaming a new motor design for the accident, the article states, “The motor performed as expected, these people said, including shutting down once sensors detected problems with the flight.”

I will note that the article's co-author, Andy Pasztor, has a reputation for writing inaccurate articles about NewSpace companies.


  1. he father of the Virgin Galactic pilot who survived the crash has hit out at the ‘rush’ to blame human error.
    Within days of the tragedy, National Transportation and Safety Board (NTSB) staff claimed co-pilot Michael Alsbury, who died, wrongly flicked a safety switch controlling the rocket’s folding wings.
    That would cause them to deploy at an unsafe speed and ‘feather’ – slowing down the rocket. But Dr Klaus Siebold, father of surviving pilot Peter Siebold, claimed a second switch would have had to be deployed to cause feathering.
    Dr Siebold, himself a pilot and flight instructor, said: ‘Turning the safety lever won’t automatically feather the tail.
    ‘The fact that the tail was feathered without a pilot ordering it to do so suggests a mechanical problem, not pilot error.
    ‘It’s really irresponsible for the NTSB to suggest a possible explanation for the accident with months of investigation still to come.

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  2. Marek, I tend to agree. The feathers shouldn't deploy just because they've been unlocked. As I noted, Mr. Pasztor has a reputation for inaccurate reporting, writing articles that protect the vested interests of certain parties. That's why I noted his reputation in the article.

    1. One clue that NTSB gave was creation of a special human-machine interface group - I think they suspect that the way displays of SS2 are designed contributed to (or even caused) the error. I cannot believe that a very experienced pilot flying a test flight would accidentally make such an error.