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Virgin Galactic pilot recalls colleague's crash

44 points by Robadob 11y ago

Shivetya 11y ago
I had not realized how delayed this project had become, crash or no crash. It does seem odd that something so vital to the safety of the craft wasn't protected by systems to warn the pilots. It might be, but I am thinking along the lines of treating it like stall warnings or such or having an interlock that cannot be thwarted easily
PaulRobinson 11y ago
There is a really good piece from Newsnight on Virgin Galactic: https://www.youtube.com/watch?v=M-gxmqUfQ80 https://www.youtube.com/watch?v=M-gxmqUfQ80 I would encourage you to watch all of if you're interested in Virgin Galactic. It is pretty clear to me that they have one last chance to get this right. If they suffer another catastrophic failure any time in their next 4-5 flights, they will need to shut down. The fact they do not seem to be addressing design flaws concerns me. If I were a customer I'd be seeking a refund. I hope my pessimism proves to be unfounded and they usher in a new era, but right now it must be hard for all of them over there.
- 7952 11y ago
  I am not an engineer, but it occurs to me that high-velocity aerodynamic flight is still a seriously difficult problem; and one best avoided if not actually neccessary. The resemblance to an aicraft hides the fact that it is something completely different at various stages of its flight. And in all these stages there are different problems that could occur, and limited experience of those issues.
  - Gravityloss 11y ago
    Looking at it from another angle, configuration changes are often a source of problems. So here the plane has two aerodynamic configurations, aircraft mode and shuttlecock mode. (Technically being carried is also one, and being a rocket vs glider is debatable.) Now the wrong mode was entered at the wrong time, more precisely at the wrong dynamic pressure (altitude and speed) and disaster struck. It'd be nice to avoid having to have such modes but with current power sources it's probably unavoidable to have some. Staging is a mode change as well. (If you were powered by say, antimatter, you could make the rocket a big stainless steel ball with just a powerful engine that could take anything and fly in any attitude, almost at any speed at any altitude without breaking up. Aerodynamic moments would be tiny.) Airplanes also have mode limitations, like that you can't extend the landing gear at high speeds.
codeulike 11y ago
No new info there. We've known for ages that one of the pilots unlocked the feathering system at the wrong time.
Already__Taken 11y ago
I'm sceptical how the co-pilot somehow did the single most wrong thing to this aircraft possible (unhinging the wing). There must be some interesting report to be had on how design can kill if that is what went wrong. It's a fun exercise think about how this kind of failure can be compensated while always having to ask, what if that compensation also fails. The flight computer could easily work out that the wing can only be unlocked AFTER the violent acceleration only during a complete free-fall, but then it's no problem thinking of a hundred ways that computer could fail. Plus you probably want a manual override anyway to the lock etc. If that was actually my job I'd never sleep easy.
- codeulike 11y ago
  Its an experimental aircraft doing test flights, I don't think they spend a lot of time trying to make it blunderproof. Theres a million things the test pilots could do to endanger the craft. I imagine they mostly just assume that the pilots will not mess up.
  - xanderstrike 11y ago
    Exactly. A pilot could also fly it into the ground, or into a building, or into WKII. Do we need physical safety mechanisms to prevent this? Or can we depend on pilot training?
- tjradcliffe 11y ago
  More importantly, there are a bunch of scenarios where the wing needs to swing that don't involve the pre-conditions you've specified. No one knows what they are, but we know they exist--because they always do--and the last thing needed is for the computer to tell the pilot, "I'm sorry I can't do that Dave" when the pilot tries to do something it has been programmed to not allow. At that point a software developer's imagination is flying the aircraft, which is never a good thing. That we can't imagine those scenarios right now is irrelevant to this point: we can't imagine the correct physics beyond the standard model, either. That doesn't mean we won't discover it as we gather more data. But in the aircraft industry "more data" often involves dead people. We generally find it easy to reason like, "In context X do (or don't do) Y until condition Z." The hard part is figuring out what consquences that will have in context P, Q or R... each of which is likely to have a very low probability, but one of which is almost certain to happen eventually.
imglorp 11y ago
I'm curious what's the government restriction to photography of the assembly process. Is this an export controls thing? First, you can already see this stuff on youtube. And second, there are some advancements here but they seem of more commercial interest than military. And third, they're still having engine trouble (they just did a major tech pivot) so it's not clear you'd want to copy it anyway.
- vermontdevil 11y ago
  It's the ITAR: https://www.pmddtc.state.gov/regulations_laws/itar.html https://www.pmddtc.state.gov/regulations_laws/itar.html
- Tloewald 11y ago
  My guess is it's Richard Branson's knack for self promotion.
ohitsdom 11y ago
What's with the title? No details have emerged (although the full report is due in a few months). Even BBC's title is misleading. "Virgin Galactic pilot recalls colleague's crash"- he said he couldn't see anything.
- sctb 11y ago
  We changed the title from "Virgin Galactic crash details emerge" to that of the article.
  - Robadob 11y ago
    That was the original title at the time of submission, they appear to have updated the title (and maybe the article) since.
throwaway12357 11y ago
Reading this I can't help comparing it against SpaceX. SpaceX is actually 2 years older than Virgin. But SpaceX is Getting Things Done at warp speed for some years now, while Virgin Galactic keeps having multiple crashes. Despite SpaceX having a harder mission. Is it all due to the Elon Musk effect? What's the secret?
- deleted 11y ago
  [deleted]
- 7952 11y ago
  Why is the SpaceX missions harder? Only a couple of aeroplanes have ever gone more than mach 3, and with significant difficulty. In comparison there are numerous rocket launch vehicles with thousands of successful launches. The atmosphere is a very hostile place and aerodynamic control is not trivial.
  - mikeash 11y ago
    Getting stuff into a suborbital trajectory is basically a subset of getting stuff into orbit. It's basically like, if you can drive from NYC to LA, you can drive from NYC to Chicago. It could very well be that Virgin's chosen approach is more difficult because they are using airplanes instead of rockets. But nothing forced them to choose that approach, and it's not the mission. If you find it harder to get to Chicago than I do to get to LA because I'm driving a car and you're using a kayak, that doesn't mean your mission is harder.
    - _mulder_ 11y ago
      Except a car costs $30,000 and a Kayak costs $300 with much lower running costs. Virgin are not trying to be the first to get into Space, they're trying to reduce the cost and make it more affordable.
      - mikeash 11y ago
        Lower cost of access to space is SpaceX's big goal as well. So far they're doing much better at it. I wouldn't be surprised if SpaceX could meet Virgin's price for a suborbital trip, if they felt it was worth their while. But they have vastly larger fish to fry.
nedwin 11y ago
It's a tough problem to solve but Virgin Galactic have claimed they will be ready for passengers "in less than 2 years) every year since they launched. In 2004.

44 points by Robadob 11y ago

I had not realized how delayed this project had become, crash or no crash. It does seem odd that something so vital to the safety of the craft wasn't protected by systems to warn the pilots. It might be, but I am thinking along the lines of treating it like stall warnings or such or having an interlock that cannot be thwarted easily

PaulRobinson 11y ago

There is a really good piece from Newsnight on Virgin Galactic: https://www.youtube.com/watch?v=M-gxmqUfQ80 https://www.youtube.com/watch?v=M-gxmqUfQ80 I would encourage you to watch all of if you're interested in Virgin Galactic. It is pretty clear to me that they have one last chance to get this right. If they suffer another catastrophic failure any time in their next 4-5 flights, they will need to shut down. The fact they do not seem to be addressing design flaws concerns me. If I were a customer I'd be seeking a refund. I hope my pessimism proves to be unfounded and they usher in a new era, but right now it must be hard for all of them over there.

7952 11y ago
I am not an engineer, but it occurs to me that high-velocity aerodynamic flight is still a seriously difficult problem; and one best avoided if not actually neccessary. The resemblance to an aicraft hides the fact that it is something completely different at various stages of its flight. And in all these stages there are different problems that could occur, and limited experience of those issues.
- Gravityloss 11y ago
  Looking at it from another angle, configuration changes are often a source of problems. So here the plane has two aerodynamic configurations, aircraft mode and shuttlecock mode. (Technically being carried is also one, and being a rocket vs glider is debatable.) Now the wrong mode was entered at the wrong time, more precisely at the wrong dynamic pressure (altitude and speed) and disaster struck. It'd be nice to avoid having to have such modes but with current power sources it's probably unavoidable to have some. Staging is a mode change as well. (If you were powered by say, antimatter, you could make the rocket a big stainless steel ball with just a powerful engine that could take anything and fly in any attitude, almost at any speed at any altitude without breaking up. Aerodynamic moments would be tiny.) Airplanes also have mode limitations, like that you can't extend the landing gear at high speeds.

codeulike 11y ago

No new info there. We've known for ages that one of the pilots unlocked the feathering system at the wrong time.

Already__Taken 11y ago

I'm sceptical how the co-pilot somehow did the single most wrong thing to this aircraft possible (unhinging the wing). There must be some interesting report to be had on how design can kill if that is what went wrong. It's a fun exercise think about how this kind of failure can be compensated while always having to ask, what if that compensation also fails. The flight computer could easily work out that the wing can only be unlocked AFTER the violent acceleration only during a complete free-fall, but then it's no problem thinking of a hundred ways that computer could fail. Plus you probably want a manual override anyway to the lock etc. If that was actually my job I'd never sleep easy.

codeulike 11y ago
Its an experimental aircraft doing test flights, I don't think they spend a lot of time trying to make it blunderproof. Theres a million things the test pilots could do to endanger the craft. I imagine they mostly just assume that the pilots will not mess up.
- xanderstrike 11y ago
  Exactly. A pilot could also fly it into the ground, or into a building, or into WKII. Do we need physical safety mechanisms to prevent this? Or can we depend on pilot training?
tjradcliffe 11y ago
More importantly, there are a bunch of scenarios where the wing needs to swing that don't involve the pre-conditions you've specified. No one knows what they are, but we know they exist--because they always do--and the last thing needed is for the computer to tell the pilot, "I'm sorry I can't do that Dave" when the pilot tries to do something it has been programmed to not allow. At that point a software developer's imagination is flying the aircraft, which is never a good thing. That we can't imagine those scenarios right now is irrelevant to this point: we can't imagine the correct physics beyond the standard model, either. That doesn't mean we won't discover it as we gather more data. But in the aircraft industry "more data" often involves dead people. We generally find it easy to reason like, "In context X do (or don't do) Y until condition Z." The hard part is figuring out what consquences that will have in context P, Q or R... each of which is likely to have a very low probability, but one of which is almost certain to happen eventually.

imglorp 11y ago

I'm curious what's the government restriction to photography of the assembly process. Is this an export controls thing? First, you can already see this stuff on youtube. And second, there are some advancements here but they seem of more commercial interest than military. And third, they're still having engine trouble (they just did a major tech pivot) so it's not clear you'd want to copy it anyway.

vermontdevil 11y ago
It's the ITAR: https://www.pmddtc.state.gov/regulations_laws/itar.html https://www.pmddtc.state.gov/regulations_laws/itar.html
Tloewald 11y ago
My guess is it's Richard Branson's knack for self promotion.

ohitsdom 11y ago

What's with the title? No details have emerged (although the full report is due in a few months). Even BBC's title is misleading. "Virgin Galactic pilot recalls colleague's crash"- he said he couldn't see anything.

sctb 11y ago
We changed the title from "Virgin Galactic crash details emerge" to that of the article.
- Robadob 11y ago
  That was the original title at the time of submission, they appear to have updated the title (and maybe the article) since.

throwaway12357 11y ago

Reading this I can't help comparing it against SpaceX. SpaceX is actually 2 years older than Virgin. But SpaceX is Getting Things Done at warp speed for some years now, while Virgin Galactic keeps having multiple crashes. Despite SpaceX having a harder mission. Is it all due to the Elon Musk effect? What's the secret?

deleted 11y ago
[deleted]
7952 11y ago
Why is the SpaceX missions harder? Only a couple of aeroplanes have ever gone more than mach 3, and with significant difficulty. In comparison there are numerous rocket launch vehicles with thousands of successful launches. The atmosphere is a very hostile place and aerodynamic control is not trivial.
- mikeash 11y ago
  Getting stuff into a suborbital trajectory is basically a subset of getting stuff into orbit. It's basically like, if you can drive from NYC to LA, you can drive from NYC to Chicago. It could very well be that Virgin's chosen approach is more difficult because they are using airplanes instead of rockets. But nothing forced them to choose that approach, and it's not the mission. If you find it harder to get to Chicago than I do to get to LA because I'm driving a car and you're using a kayak, that doesn't mean your mission is harder.
  - _mulder_ 11y ago
    Except a car costs $30,000 and a Kayak costs $300 with much lower running costs. Virgin are not trying to be the first to get into Space, they're trying to reduce the cost and make it more affordable.
    - mikeash 11y ago
      Lower cost of access to space is SpaceX's big goal as well. So far they're doing much better at it. I wouldn't be surprised if SpaceX could meet Virgin's price for a suborbital trip, if they felt it was worth their while. But they have vastly larger fish to fry.

nedwin 11y ago

It's a tough problem to solve but Virgin Galactic have claimed they will be ready for passengers "in less than 2 years) every year since they launched. In 2004.