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Thread: Virgin Galactic Accident

  1. #21
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    The BBC is reporting "Air safety chief Christopher Hart said the "feathering" device, designed to slow the craft on re-entry, activated without a command from the pilots. But he said it was too soon to confirm any possible cause of the crash.

    Looking back at the photos the 'wings' do seem far out compared with the recessed configuration on release. While that could be the effect of an explosion the bits that fell to earth don't seem to have suffered too badly from burn marks.

    So it might not have been the motor. Shows the danger of jumping to 'obvious' conclusions. Time will tell.

    http://www.bbc.co.uk/news/world-us-canada-29876154

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    Quote Originally Posted by Brainsys View Post
    The BBC is reporting "Air safety chief Christopher Hart said the "feathering" device, designed to slow the craft on re-entry, activated without a command from the pilots. But he said it was too soon to confirm any possible cause of the crash.

    Looking back at the photos the 'wings' do seem far out compared with the recessed configuration on release. While that could be the effect of an explosion the bits that fell to earth don't seem to have suffered too badly from burn marks.

    So it might not have been the motor. Shows the danger of jumping to 'obvious' conclusions. Time will tell.

    http://www.bbc.co.uk/news/world-us-canada-29876154
    Too violent shaking and the component couldnīt withstand it?
    "The real CEO of the 787 project is named Potemkin"

  3. #23
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    More from The Register:

    “About nine seconds after the rocket engine ignited, the telemetry data showed us that the feather parameters changed from lock to unlock," Hart explained. "In order for this action to be commanded by the pilots, two actions must occur: the lock/unlock handle must be moved and the feathering handle must be moved to the feather position."

    According to Hart, cockpit video showed that co-pilot Michael Alsbury manually unlocked the feather system but didn't then select feather mode on the feathering handle. However the tail booms nonetheless folded upwards and the craft cracked up.

    “Approximately two seconds after the feathering parameters indicated that the lock/unlock lever was moved, the feathers moved toward the extended position, even though the feather handle itself had not been moved," Hart went on. "This occurred at a speed just above approximately Mach 1.0. Shortly after the feathering occurred, the telemetry data terminated and the video data terminated."


    More here: http://www.theregister.co.uk/2014/11..._tragic_crash/

    If it were caused by an unscheduled deployment then the cause (software or mechanical) should be straightforwardly fixable. Unlike a dodgy rocket motor. That may make it more likely that the programme is technically recoverable. Though whether the market in rich superstars has been smashed with the airframe is another matter.

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    Yesterday's NTSB briefing is available here:
    https://twitter.com/NTSB
    Give a description of the "feather" system.

  5. #25
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    Quote Originally Posted by guamainiac View Post
    It looks like the engine continued on unless that is a smudge or distortion
    The early report today suggests that they configured it for the glide while still accelerating under thrust and apparently this caused the airframe to fail. There is something like an unlock lever and a deploy lever and the copilot deployed the unlock lever and then the configuration deployed without the second lever being touched. Part pilot error, part system malfunction, apparently. I guess the good news is that the engine and fuel were not at fault and the system malfunction should be fairly easy to fix.

    Does anyone know if this was their only 'spaceworthy' airframe?

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    Is it at all possible with such an engine, as opposed to a solid fuel motor, that such a slow down may cause a momentary surplus of unburnt fuel that suddenly ignites.

    It also sounds like they have a very basic problem with cockpit ergonomics if such a control fell so readily to hand. A friend of mine worked on part of the instrument placement for a B-1 component and if it was looked at by one it was looked at by 20 engineers before the pilots got to tear it apart so as to avoid such errors.
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    Quote Originally Posted by guamainiac View Post
    Is it at all possible with such an engine, as opposed to a solid fuel motor, that such a slow down may cause a momentary surplus of unburnt fuel that suddenly ignites.

    It also sounds like they have a very basic problem with cockpit ergonomics if such a control fell so readily to hand. A friend of mine worked on part of the instrument placement for a B-1 component and if it was looked at by one it was looked at by 20 engineers before the pilots got to tear it apart so as to avoid such errors.
    Well, their budget is a tad bigger than this project.
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    Quote Originally Posted by brianw999 View Post
    Either or really. The craft is designed to go into space so this would be the most appropriate forum. More important really about all this is that another person has lost their life advancing the bounds of aviation.
    I agree with you Brian. This accident reminds me the two Space Shuttle Accidents (Columbia and Challenger) and also a reminder that Space exploration is not accident free.
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    NTSB press conference:
    https://www.youtube.com/watch?v=vjYV...ature=youtu.be

    Main points, in chronological order:
    - The ship released normally from the mother ship.
    - The engine ignited normally.
    - The "lock-unlock" lever for the feather position was moved by the copilot from the locked to the unlocked position (confirmed by telemetry and in-cockpit video), when the speed was about M 1.0. He was not supposed to do that until they reached M 1.4 at a higher altitude (which, I presume, regardless of the higher speed, would impose lesser aerodynamic forces due to the lower air density, but this act by itself should not result in the feathers moving anyway).
    - The "feather" handle was not moved (conformed by in-cockpit video). For the feathers to be moved into the "feather" position both actions are required by design (at least as intended): That the "lock-unlock" lever is moved to "unlocked" and that the "feather" lever is moved to the "feather" position.
    - Yet, the feathers moved uncommandedly to the "feather" position (confirmed by telemetry and video from outside).
    - The ship broke apart 2 seconds later.
    - The fuel tank, oxidizer tank and engine were recovered intact with no signs of breach or burn through.

    I loved the last question: "Can this happen to another airplane?"

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  10. #30
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    In answer to my own question, this was reportedly their only operational testbed. A number of others are being assembled but no word on when they will have another testbed to proceed.

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    This site gives a good description of the planned flight trajectory for Spaceship Two. The "feathers" are used only after the vehicle has reached apogee.
    http://blogs.scientificamerican.com/...ed-tails-work/

    To rotate the "feathers" through 90 degrees then return them there must be an actuator mechanism. My guess is that this mechanism either failed or it received a premature activation signal.

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    Quote Originally Posted by Evan View Post
    In answer to my own question, this was reportedly their only operational testbed. A number of others are being assembled but no word on when they will have another testbed to proceed.
    The report I read (sorry cannot recall the source) was that another spaceframe(?) was 65% complete and they would continue building. I guess one of the issues is that the investigators must want to see what a real cockpit looks and feels like. Something you can't always get from drawings or computer simulations. Especially if human factors are at issue here - the premature unlock.

    As for unscheduled deployment - do we presume the 'shock' around mach 1.0 may have triggered something? A reason to keep it locked till safely through that zone?

  13. #33
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    So, this is a two-barrier system. There is a "lock/unlock" lever and another "feather" lever and you have to move both of them, in sequence, to go to the feather configuration. According to the NTSB, the first lever was moved but the second not, and per intended design the feather should have stayed in the normal position with that action alone. If that's correct, then pilot error" alone doesn't explain it (even if we narrowly look just for the immediate cause).

    I wonder if the "lock/unlock" handle just locks the "feather" handle to prevent that the "feather" lever is unintentionally moved (but moved) by the crew, or it actually mechanically locks the feather in the "normal" position to prevent a known potential failure mode that would cause the ship to go in the feather config even without touching the feather lever.

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  14. #34
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    Quote Originally Posted by Gabriel View Post
    I wonder if the "lock/unlock" handle just locks the "feather" handle to prevent that the "feather" lever is unintentionally moved (but moved) by the crew, or it actually mechanically locks the feather in the "normal" position
    IMHO the answer should be "both"! Given the apparent serious consequences when the system deploys at the wrong time.

    On an unrelated note: does anyone know what the criteria/rules are for when the NTSB does or does not investigate an accident such as this?

    They obviously investigate airplane accidents, but I don't think they've ever investigated one involving a NASA spacecraft, nor do I think they're investigating the recent Antares rocket failure.
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    Is amazing one of the crew member survived a plunge from 50,000 Ft. with a parachute. Parachutes are not designed for such altitudes, and their flight suits were not designed for this kind of cold atmosphere.
    I remember Chuck Yeager jumped from an F-105 from 70,000 ft., during an emergency. And a test pilot from the SR-71 jumped from 60,000 ft when the airplane broke in pieces, in 1966.
    But still, they need a "space suit" designed for this kind of altitudes. Something the crew of the Virgin Galactic didn't have.
    Amazing!
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    Quote Originally Posted by elaw View Post
    On an unrelated note: does anyone know what the criteria/rules are for when the NTSB does or does not investigate an accident such as this?

    They obviously investigate airplane accidents, but I don't think they've ever investigated one involving a NASA spacecraft, nor do I think they're investigating the recent Antares rocket failure.
    This was not a rocket in the Antares sense but an aircraft with a rocket pack - as are often (ok not exclusively) used on some conventional aircraft to assist with take off etc. The plane was airborne due to lift on the body/wings, control was, presumably, through aileron type surfaces. Indeed the whole flight envelope is just like those 'weightless' experience flights with a little more whoomph. The wreckage also had N- (US) aircraft registrations. Do NASA rockets have those?

    More interestingly - was the old shuttle a plane too? Or because it could stay in space be regarded as a spacecraft?

    I do find it challenging to regard SS2 as a spacecraft. Indeed is there really not that much difference between the experience it gives and a high flying ride in a MIG-29 skimming either side of a notional division between space and atmosphere?

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    I wonder if the FO took a short cut anticipating the actuation of the feathers by lifting the protective cover ahead of time?

    I live not too far from a Naval Air weapons practice range and a few years back we had a pilot riddle an elementary school with cannon fire when the pilot lifted the cover from the "pickle" before he "went over the top" on his gun run. Apparently he hit some turbulence and he brushed the button to fire. No one injured but with luck it was after school and the custodians just finished cleaning that wing; lots of holes in the roof and smashed desks.

    Probably not, but the premature lifting of the cover reminded me of that.
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  18. #38
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    Quote Originally Posted by AVION1 View Post
    Is amazing one of the crew member survived a plunge from 50,000 Ft. with a parachute. Parachutes are not designed for such altitudes, and their flight suits were not designed for this kind of cold atmosphere.
    I remember Chuck Yeager jumped from an F-105 from 70,000 ft., during an emergency. And a test pilot from the SR-71 jumped from 60,000 ft when the airplane broke in pieces, in 1966.
    But still, they need a "space suit" designed for this kind of altitudes. Something the crew of the Virgin Galactic didn't have.
    Amazing!
    I don't think an F-105 could ever make it to 70,000 ft. AVION1. F-105's most likely had a service ceiling of between 45,000 to 50,000 ft.

    Perhaps you are thinking of an F-104 (Starfighter?) I believe one or two F-104's were converted to fly up to extremely high altitudes with the assist of an added rocket engine installed in the tail?

  19. #39
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    OK here we go. I took a moment to check to be sure of my comment. It must have been the F-104, the conversion was called the NF-104A.

    The link below also makes mention of Chuck Yeager ejecting from an NF-104A.

    I am not aware of any F-105's that were converted to rocket planes for extreme altitude flying? Any one?

    Link:

    http://en.wikipedia.org/wiki/Lockheed_NF-104A
    Last edited by Rick G; 11-06-2014 at 03:08 AM. Reason: Spelling correction

  20. #40
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    I don't know the NTSB charter exactly.

    But the NTSB is the National TRANSPORTATION Safety Board (not the National Aviation Safety Board). They investigate not only aviation accidents, but also highway, railroad, maritime and even pipelines.

    I know that military accidents are specifically excluded.
    I don't know how NASA accidents qualify in all this.

    But in this specific case, remember that it was a commercial endeavor in the development of a vehicle to take passengers on an entertainment flight to the boundaries of the atmosphere for a fee. It looks quite appropriate that the NTSB is investigating.

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