Virgin Galactic Accident

[brianw999]

Why in the military aviation forum?
There is another thread in the aviation safety forum.

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.

[elaw]

Brian,

Do you have any way of merging the two threads?

I imagine there's going to be a lot of discussion about this and it would stink to have it split between two threads.

[brianw999]

Certainly can merge threads. On an iPad right now, I'll see if I can do it without screwing it up.

[brianw999]

By George....I think i did it ? Wonders will never cease.

[Gabriel]

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.

Gotcha. Had missed the "space" part of this forum.

[Brainsys]

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

[Alessandro]

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 couldn´t withstand it?

[Brainsys]

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.

[Highkeas]

Yesterday's NTSB briefing is available here:

https://twitter.com/NTSB

Give a description of the "feather" system.

[Evan]

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?

[guamainiac]

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.

[Alessandro]

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.

[AVION1]

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.

[Gabriel]

NTSB press conference:

https://www.youtube.com/watch?v=vjYVhGvUSNc&feature=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?"

[Evan]

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.