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Space Technology

SpaceShipTwo's Rocket Engine Did Not Cause Fatal Crash 150

astroengine writes It wasn't SpaceShipTwo's hybrid rocket motor — which was flying on Friday with a new type of fuel — that caused the fatal crash, the head of the accident investigation agency said late Sunday. The ship's fuel tanks and its engine were recovered intact, indicating there was no explosion. "They showed no signs of burn-through, no signs of being breached," Christopher Hart, acting chairman of the National Transportation and Safety Board, told reporters at the Mojave Air and Space Port in Mojave, Calif. Instead, data and video relayed from the ship show its hallmark safety feature — a foldable tail section designed for easy re-entry into the atmosphere from space — was deployed early, causing the in-flight break-up.
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SpaceShipTwo's Rocket Engine Did Not Cause Fatal Crash

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  • by rossdee ( 243626 ) on Monday November 03, 2014 @09:00AM (#48300445)

    Why does it need a foldable tail? Its not like it reenters at orbital velocities...

    • Re:Foldable tail? (Score:5, Informative)

      by LWATCDR ( 28044 ) on Monday November 03, 2014 @09:04AM (#48300471) Homepage Journal

      Because you do not need to be anywhere near orbital velocities for friction to be an issue. The SR-71 cruises at around 1/9th orbital velocity and had a lot of heat issues to deal with.
      It needs the foldable tail to create a stable, high drag configuration to get it safely down to denser air.

    • Re:Foldable tail? (Score:4, Informative)

      by trout007 ( 975317 ) on Monday November 03, 2014 @09:17AM (#48300573)

      The main issue is the aerodynamic forces are enough that if you aren't pointed in the right direction it could destroy the aircraft. The worry was during reentey but if this report is correct it shows you how the wrong orientation can cause breakup.

    • Re: (Score:3, Informative)

      by AlecC ( 512609 )

      Because the foldable tail puts into a very stable configuration, removing the need for attitudinal jets, because reasonable sized flaps would not work in the very thin atmosphere.

    • Confused Reporter (Score:3, Insightful)

      by sycodon ( 149926 )

      What the reporter states doesn't make sense.

      If there was a structural failure related to the tail, one would imagine it would be because it was deployed while the vehicle was traveling faster than the design speed for the tail, causing greater than planned aerodynamic stresses. Saying it failed because they were going slower than the normal deployment speed just doesn't make sense. Things break when you overstress them, not when you under-stress them.

      Am I missing something?

      • by trout007 ( 975317 ) on Monday November 03, 2014 @09:33AM (#48300711)

        The tail is supposed to be deployed during rentey at an altitude where the air is thin. So even though you are going faster the air is thin so the loads are less.

      • What the reporter states doesn't make sense.

        ... Saying it failed because they were going slower than the normal deployment speed just doesn't make sense.

        I was first thinking along the same line also but the air density at 15km is much higher than at 100km. Even so I was under the impression that the feather is deployed at a slower speed near the apex of the flight.

        • by TWX ( 665546 )
          Stoichiometry bitches!

          Seriously, the tail was designed to function with a certain amount of pressure applied to it. That pressure happens to be that which is seen at a certain altitude at a particular range of vehicle speeds. For that to function at a lower altitude with higher ambient air pressure, the speed must be reduced. Try it when the speed is too high and this happens.
          • by Anonymous Coward

            Stoichiometery has to do with chemical reactions, not pressure/drag/etc. There is literally nothing in this story or your explanation that has anything to do with stoichiometery.

            • by TWX ( 665546 )
              Okay, so I messed up. I meant STP. It's morning and I haven't had my coffee yet.
      • >> What the reporter states doesn't make sense.

        I've seen even worse coverage of this. A local TV station bubblehead read the text of the Virgin accident story against the video of the Antares rocket exploding. (No footage of the Virgin crash, no tie-in between Antares and Virgin explained, just "private space death" story audio over the biggest explosion they could find.)

      • Not "deployed", "unlocked". Presumably there is an "arm" step and then a "deploy" step.

        • Re: (Score:2, Informative)

          by Anonymous Coward

          Indeed. From The Guardian [theguardian.com]:

          Christopher Hart, the acting chairman of the US National Transportation Safety Board, told a press conference on Sunday night that the co-pilot, Michael Alsbury, had unlocked the feathering system, but that the second stage of the process, which moves the wings into the feathering position, happened “without being commanded”.

          And here's a short video from the press conference [bbc.co.uk].

      • Re: (Score:3, Interesting)

        by Anonymous Coward

        Supposed SOP was to unlock (NOT DEPLOY, unlock) the feather at Mach 1.4.

        Logic being that if it doesn't unlock, thrust is cut and the flight aborted. Past that point you are committed to climbing at such speed that the re-entry without the feathering system could be fatal.

        Actual deploy would happen only past apogee and the feather mode would stabilize the fall and give high drag before the craft enters denser parts of the atmosphere.

        For some reason the deploy happened uncommanded right after unlock and Bad T

        • Re:Confused Reporter (Score:5, Informative)

          by ConfusedVorlon ( 657247 ) on Monday November 03, 2014 @12:35PM (#48302361) Homepage

          the video seems to state:

          1) SOP is to unlock at 1.4
          2) the co-pilot moved the lever to unlock at 1.0

          "the lock unlock is not to be moved into the unlock position until acceleration up to mach 1.4. Instead, that occurred at approximately mach 1.0"
          http://www.bbc.co.uk/news/worl... [bbc.co.uk] (2:50)

          I don't know if that difference is significant. It sounded to me like 'we're not casting blame formally yet, but look over here at this pilot error'

          • I am wondering if anything holds the mechanism in place if it is unlocked. Otherwise the aerodynamic forces should deploy the mechanism if they try to pull the ship up.
          • by Kevin Fishburne ( 1296859 ) on Monday November 03, 2014 @04:12PM (#48304451) Homepage
            Maybe I've been watching too much Star Trek (okay, not maybe), but shouldn't the execution of operations that could single-handedly destroy the craft require an override when being executed outside safe parameters? I understand the danger of having the computer prevent you from doing what you think needs to be done at the time, but having an "are you sure?" prompt when the computer thinks you're fucking up sounds like a good idea to me.
      • by Luckyo ( 1726890 )

        Air pressure.

        Tail is designed to deploy in extremely thin atmosphere to stabilize the aircraft. Deploying it in much thicker atmosphere causes far more drag than deploying it in extremely thin atmosphere at much higher speed.

    • Its not like it reenters at orbital velocities...

      Okay, I'm irritated at the world today...

      Pedant Mode...ON.

      "Orbital SPEEDS" is probably the phrase you were groping blindly for when you typed the above.

      Given sufficient speed, the direction vector that would turn that "speed" into "velocity" only has to meet one requirement - that it not intersect the ground.

      And even that is technically moot - even if your "orbit" intersects the ground, it's still technically a ballistic orbit as long as the forces actin

    • The shuttlecock-like folding tail is a key design element in both ApaceShip One and Two: it provides a simple way of decelerating during atmospheric re-entry without the need for complex control electronics. This will be even more important in an orbital design.

    • Re:Foldable tail? (Score:4, Informative)

      by sjbe ( 173966 ) on Monday November 03, 2014 @10:09AM (#48301011)

      Why does it need a foldable tail? Its not like it reenters at orbital velocities...

      Because it assists with the descent. The craft falls back to earth something like a badminton shuttlecock. Not a perfect analogy but it's a fairly clever way to ensure flight stability in a very simple manner.

  • "The engine burn was normal up until the extension of the feathers," said Hart.

    Normally, the feather system wouldn’t be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound.

    Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said.

    [...]

    The accident claimed the life of Scaled Composites test pilot Mike Alsbury, who was serving as the spaceship co-pilot, Scaled’s website shows. Pilot Pete Siebold, who was able to parachute to the ground, survived with a serious shoulder injury.

    This will be amusing to watch the fallout. (Note: the incident itself is not amusing, but rather the nutjobs who will come up with some, shall we say, interesting theories.)

    In other news, I've got some gently used chemtrails for sale. Just $20/gram! Get yer chemtrails!

    • shift inter-locks (Score:5, Insightful)

      by bill_mcgonigle ( 4333 ) * on Monday November 03, 2014 @09:20AM (#48300605) Homepage Journal

      Normally, the feather system wouldn't be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound.
      Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said.

      Modern cars have a feature where you can't take the key out of the ignition if you forget to put the thing in park. This feature saves me from stupid about twice a year. Humans are error-prone - there's a whole field, poka yoke [wikipedia.org] dedicated to preventing these sorts of errors.

      Test pilots are the best of the best. If one of them can make a catastrophic mistake then so can any commercial pilot.

      Now, they may have figured that that sort of safety gear was "for later" and test craft are often bare-bones, and test pilots are often relied on to not make those kinds of mistakes. Assuming the premise here, we might see more automation early in the design process going forward. Virgin might be able to survive a year-long investigation but that kind of delay is an ongoing liability. It may turn out to be faster and cheaper in the long run to add in those costs up front, if delays are calculated into the cost.

      • by Anonymous Coward

        THANK YOU!

        (first genuinely useful signature I've seen)

      • It's always a tricky design decision though. Certainly, the best of us can make mistakes, and the operator is the most unpredictable component.

        But then the designers are stil in the debugging stage. It is possible that there's an unforseen circumstance where activating the feather system at the wrong time is exactly what the pilot needs to do, and he doesn't want the system telling him not to do that.
        • by FlyHelicopters ( 1540845 ) on Monday November 03, 2014 @11:25AM (#48301599)

          It is possible that there's an unforseen circumstance where activating the feather system at the wrong time is exactly what the pilot needs to do, and he doesn't want the system telling him not to do that.

          This...

          As a commercial pilot, I can tell you that automatic everything is nice, when it works...

          But you always want to have a manual reversion mode just in case...

          And when all else fails, a professional crew who can think can do amazing things:

          http://en.wikipedia.org/wiki/U... [wikipedia.org]

          • Railway signalling (Score:5, Interesting)

            by M0HCN ( 2981905 ) on Monday November 03, 2014 @02:49PM (#48303681)

            There is an interesting counterpoint to this in victorian era railway signalling systems.

            Now the operator interface for these consisted of banks of levers that worked the signals and points by means of a system of wires running over pullys, visibility from the signalboxes was not always brilliant and especially in fog keeping track of what was where was problematic.
            In a fit of absolute genius it was realised that the (mechanical) logic could be implemented so as to prevent a signal being set at green if the segment was occupied and also to prevent the points in an occupied section being moved (this in an age before Turing, you will note). This was clearly a good thing, right?

            Well, the signal men protested that sometimes they had to do the unusual and that they were highly experienced professionals (all the usual) and the system was modified so that a special key could be used to override the interlock logic, this key being held by the supervisors office.
            So many train crashes over the following few years featured that key, that it ended up being UK practise that any collision between trains that caused a fatailty would automatically result in the signalman being arrested on suspicion of manslaughter.

            It is a fine line between stopping the professional applying an override to fix a critical situation and leaving them able to tear the wings off by accident.

            Regards, Dan.

            • It is a fine line between stopping the professional applying an override to fix a critical situation and leaving them able to tear the wings off by accident.

              How DARE you come here and post a reasonable, well thought out response, don't you know this is the Internet! :)

              Kidding aside, you're right... Do keep in mind that those "safety systems" were also designed by the same humans that want override switches. No system is perfect.

            • So many train crashes over the following few years featured that key, that it ended up being UK practise that any collision between trains that caused a fatailty would automatically result in the signalman being arrested on suspicion of manslaughter.

              Of course the problem with that policy it is tends to change the behavior of signalmen in ways you might not expect.

              If you tell me that any use of the red key will cause me to be charged with manslaughter in the event of an accident, then my incentive is to never use it, regardless of the situation.

              --------

              What I will say is that any "fail-safe" system is designed by humans, and thus imperfect. After all, even drones crash sometimes...

              So the question becomes, what is the best balance to be had?

          • by Kjella ( 173770 )

            Which is a fair point, if you're on a regular flight with passengers. Not that pilots can't make a bad situation into an even worse cock-up. But on a test flight any percentage chance of failure with human pilots will have a higher risk of casualties than an unmanned flight. The US fly drones all over the place, there's autoland systems for airplanes and unmanned rockets go up quite often. Does this rocket plane really require pilots? And human creativity is often limited by the practical choices available

            • Re:shift inter-locks (Score:4, Interesting)

              by FlyHelicopters ( 1540845 ) on Monday November 03, 2014 @03:59PM (#48304321)

              Does this rocket plane really require pilots?

              No, probably not... most airplanes no longer "require" pilots in the sense that computers can do the job better, cheaper, and more reliability for the most part...

              The question becomes, how many passengers TODAY would get onto an airplane with no human pilots? I would, because I know better. But most people don't know any better.

              For a self-driving car I'm guessing the right emergency response is 90% braking, 9% turning, 0.9% accelerating to get out of harm's way and maybe 0.1% getting creative like unbuckling and bailing because the car's going over a cliff.

              Self-driving cars are likely to be far safer and more reliable than human-driven cars. But tell that to the mother of the dead child killed in a self-driving car? She doesn't care that 20,000 fewer people are dead in these new cars, she only cares that HER child is dead.

              Take helicopters... Here is an odd fact for you... More people are injured and killed practice autorotations than we have engine failures in helicopters.

              An autorotation is what you do when the engine quits, it lets the helicopter glide to a safe landing (sort of glide, mostly drop, but it does work).

              Frank Robinson, the owner of Robinson Helicopters (who makes the R-22 which is the most common training helicopter today) has said that he would prefer that practicing for this was no longer done for most pilot training.

              And he is right, fewer people would die if we simply accepted that anyone in a helicopter that lost the engine would just die with 100% certainty than by requiring helicopter pilots to keep practicing this over and over.

              Fully 1/4 of helicopter pilot training is practicing for losing an engine, something that doesn't actually happen to most pilots over their entire careers. Lots of pilots are hurt during training while practicing it however.

              But humans have a problem with picking any path that has a 100% certainty of death, regardless of how many people actually die on the path that is not certain.

              • by GNious ( 953874 )

                We had a lead developer visit us in Copenhagen, and as we walked past a metro entrance, he stated that he will not get in the metro cars, as they are fully automated, and he knows programmers.

      • Now I'm wondering if the feather unlock was part of the test? ugh
      • shift inter-locks (Score:3, Insightful)

        by Anonymous Coward

        Normally, the feather system wouldn't be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound.
        Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said.

        Modern cars have a feature where you can't take the key out of the ignition if you forget to put the thing in park. This feature saves me from stupid about twice a year. Humans are error-prone - there's a whole field, poka yoke [wikipedia.org] [wik

        • by Matheus ( 586080 )

          This may be considering the system as slightly less intelligent than it should be designed. There are also 2 different functions being considered:

          1) Automation: If the ship is programmed to engage feathering automatically then it requires all of the sensor input to know when to properly deploy. This needs to be very accurate as it is attempting to perform the deploy exactly when it needs to be performed with flexibility for atypical scenarios. The more data collected the better the AI at handling the craf

      • Commercial pilot here: There is a LONG tradition of blaming dead pilots for systemic flaws, so it may well be something happened other than pilot error. Having done a few test flights myself, having a copilot jsut randomly push buttons without asking would be fairly unusual to say the least.
      • by Snufu ( 1049644 )

        Human error. Humans are both the most expensive and weakest link in manned space travel.

        Unmanned space investigation can tell us more about the universe than manned projects, at a fraction of the cost.
        Why are we so determined to put meat into places where it cannot survive?

  • by T.E.D. ( 34228 ) on Monday November 03, 2014 @09:06AM (#48300485)

    Last week saw the Orbital Sciences Antares explosion on Tuesday [slashdot.org], this fatal Virgin Galactic crash on Friday, and a plane crash in Wichita [nytimes.com] on Thursday that killed 4 (The pilot, and 3 in the building it crashed into).

    Hopefully we have some good weeks ahead to balance this.

    • by I'm New Around Here ( 1154723 ) on Monday November 03, 2014 @09:14AM (#48300545)

      The three in the building were in a flight simulator. How horribly ironic.

      "You can learn to fly in this machine. It's just like the real jet, except you cannot die."

      • Well, the article says the building that was destroyed housed flight simulators, but not if they were in use. However the name of the company is FlightSafety International, which is also ironic.

      • The three in the building were in a flight simulator. How horribly ironic.

        "You can learn to fly in this machine. It's just like the real jet, except you cannot die."

        Only in an infinite universe will there exist people who were killed in a plane accident while on the ground in a flight simulator.

      • The three in the building were in a flight simulator. How horribly ironic.

        "You can learn to fly in this machine. It's just like the real jet, except you cannot die."

        Up to the moment it ceased functioning it unexpectedly became the most realistic flight simulator ever.

  • A missing detail (Score:5, Informative)

    by jbmartin6 ( 1232050 ) on Monday November 03, 2014 @09:12AM (#48300531)
    For those who won't read the article, it was unclear why the tail was deployed early. Pilot error was one possibility:

    Normally, the feather system wouldn’t be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound. Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said. “I’m not stating that this is the cause of the mishap,” he added. “We have months and months of investigation to determine what the cause was.” In addition to the possibility of pilot error, Hart said the NTSB is looking a variety of other issues that may have caused or contributed to the accident

    • Re:A missing detail (Score:4, Interesting)

      by Charliemopps ( 1157495 ) on Monday November 03, 2014 @09:30AM (#48300683)

      Right, he may very well have been trying to save it by doing that. Or scrambling unsuccessfully to find the eject lever.

    • How dare an article not jump to a conclusion before they are facts to back it up. You must be watching too much Cable News.

      I know we live in the internet age where we demand information right away. However some things takes time.

      Make sure they are keeping the investigation productive, but stop pressuring people to find who to blame so we can do a token fire of that person, then carry on like nothing has happened.
       

    • Normally, the feather system wouldn’t be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound. Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said. “I’m not stating that this is the cause of the mishap,” he added. “We have months and months of investigation to determine what the cause was. If we find the problem right away, we don't get paid nearly as much. I've been told we need to generate about $2 Million in billables before we can write up any conclusions ” In addition to the possibility of pilot error, Hart said the NTSB is looking a variety of other issues that may have caused or contributed to the accident

      I presume others read my added words as well?

      • by bledri ( 1283728 )

        Normally, the feather system wouldn’t be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound. Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said. “I’m not stating that this is the cause of the mishap,” he added. “We have months and months of investigation to determine what the cause was. If we find the problem right away, we don't get paid nearly as much. I've been told we need to generate about $2 Million in billables before we can write up any conclusions ” In addition to the possibility of pilot error, Hart said the NTSB is looking a variety of other issues that may have caused or contributed to the accident

        I presume others read my added words as well?

        Only people that are so blinded by their ideology that they assume they know "the truth" without having to bother with real world facts.

    • by swell ( 195815 )

      I'm not suggesting that this is the case at this early point in the investigation; but an industry insider who personally studies every airline 'incident' informs me that the months of investigation almost always conclude that 'pilot error' was the cause.

      He has found evidence, buried in 5000 pages of dull analysis, that in fact many crashes were due to errors in design or manufacturing. So why blame the pilot? Well, for one thing the pilot is dead and can't testify in most cases. For another, admitting mech

  • KSP (Score:5, Funny)

    by Thanshin ( 1188877 ) on Monday November 03, 2014 @09:14AM (#48300549)

    Typical KSP. You click the wrong button, unfold the lander module's legs during take off and everything goes to heck.

  • The part I don't get is why one would unlock the feathering system at the start of the burn, well before it is expected to be used -- something that the in-flight videos apparently show. I can see that keeping the feathering system locked would be a safe thing to do before the release, but was the feathering system designed to be used while SpaceShipTwo was in powered flight? I was under the impression that it was not, so it would seem prudent to keep it locked until the burn was complete. Am I missing s

  • SpaceShipTwo's Rocket Engine Did Not Cause Fatal Crash

    All they've said so far is that indications are that it was most likely not the engine that caused the crash.

    Instead, data and video relayed from the ship show its hallmark safety feature — a foldable tail section designed for easy re-entry into the atmosphere from space — was deployed early, causing the in-flight break-up.

    Who has said this?

    We can blame the headline on TFA, since it's been copied-and-pasted, but it appears that the latter is the invention of the submitter.

    So, is someone making shit up, or what?

    • To continue my rant, the article even includes this quote:

      “I’m not stating that this is the cause of the mishap,” [Hart] added.

      No-one knows why SS2 crashed yet.

      • I'll tell you exactly why it crashed. It hit the ground before it was supposed to. When it does that, it's a crash. Don't need no fancy, schmancy NTSB to arrive at that conclusion.

    • by LWATCDR ( 28044 )

      Actually all the news services said that it "exploded" and most blamed the engine.
      It was funny because when I heard this at work I was surprised since I could not figure out how a hybrid rocket could "explode". Lots of ways it could fail but explode did not make a lot of sense to me.
      A co worker said, "well I guess it can".
      I guess I should always trust my physics and chemistry classes over reporters.

      • I guess I should always trust my physics and chemistry classes over reporters.

        Frankly it's a wonder you've stayed sane this long if you've only just realised this.

        That's assuming you have stayed sane, of course.

        • by LWATCDR ( 28044 )

          Frankly I am well educated in aviation, chemistry, physics, and computer science.
          I am terrified by the fact that new services almost always get really stupid things wrong like Newsweek saying that Earhart ran out of jet fuel! If they get that wrong how much other stuff is just wrong that I am not an educated in? I mean that is a simple fact that anybody could check just by looking at the picture of her plane!
          As far as my sanity... Well that is a matter of opinion.

          • I am terrified by the fact that new services almost always get really stupid things wrong like Newsweek saying that Earhart ran out of jet fuel!

            I managed to miss that one.

            So now you have to make me aware of a new realm of stupidity in media. Gee, thanks....

          • I am terrified by the fact that new services almost always get really stupid things wrong like Newsweek saying that Earhart ran out of jet fuel!

            Well, you do have to admit that Earhart had zero reserve margin of jet fuel. Of course, she also had sufficient jet fuel supplies onboard to support a flight around the world 100 times...

  • by _bug_ ( 112702 ) on Monday November 03, 2014 @10:38AM (#48301225) Journal

    Why unlock the feathers during powered flight?

    Because if you get into space and find you can't unlock them, the aircraft is going to burn up on reentry. So you unlock them during powered flight. If they don't unlock, you can shut down the engines and still have enough atmosphere to control the aircraft and direct it out of its trajectory into space.

    Why do this during powered flight and not before, perhaps just before the aircraft is released from its carrier?

    Because the aerodynamics and stress on the aircraft at engine start are dynamic to say the least. Once under stable, powered flight there's much less risk in unlocking the feathers. The aerodynamic loads should not be high enough that they would overcome the hydraulics keeping the feathers in place after being unlocked.

    The big question right now is why did the feathers deploy. The NTSB says they saw nothing to indicate the pilots had tried to deploy them; the handle used to do this was untouched based on the internal cockpit video they have.

    It's way too early to even speculate that it even might be pilot error. That the unlock happened a couple seconds early should not have caused the feathers to deploy on their own. Unless the transition to supersonic speed induces stresses that could overcome the hydraulics and force the feathers to deploy and the unlock happened just before or during that transition.

    We need to find out why the feathers deployed before we start blaming anyone or anything.

    • I think you may be onto to something there. What I've heard is that the unlocking took place at Mach 1 when it should have been at Mach 1.4. The transition from subsonic to supersonic flight is often kind of bumpy.

  • by TheSync ( 5291 ) on Monday November 03, 2014 @12:50PM (#48302529) Journal

    This is a horrible event, but for the future of Virgin Galactic it is one of the better scenarios for the failure not to be in the rocket engine itself (which is always a challenging situation, putting the strength of materials at the edge of breaking), but instead on a faulty deployment of the feathering system. Hopefully it should be simply to work out a solution to avoid pre-mature feathering.

  • by Spy Handler ( 822350 ) on Monday November 03, 2014 @01:44PM (#48303087) Homepage Journal

    I'll bet the cause will be something really simple and stupid and mundane, like a technician installing a bolt or a relay upside down.

    I read in Bob Hoover's book, in the 50's a number of F-86's crashed when their ailerons locked up if the wings flexed a certain amount. It was due to an aileron bolt mounted upside down. They traced the source to one technician at North American factory who, when interviewed said of course he knows how those damn bolts are supposed to go, he's been doing it that same way for 15 years, ever since before WW2!

    They didn't have the heart to tell that guy how many pilots he killed.

    Coincidentally in Chuck Yeager's book, he tells the story of a pilot in his F-86 squadron -- at the time Yeager was the squadron commander -- named Emmett Hatch. (Hatch was the lone black pilot in the squadron). He was coming down on approach one day, was feeling good so he did some rolls. Then his ailerons locked up, lost all control and had to eject.

    The wing commander was a man named Col. Ascani, a really meticulous numbers guy who was obsessed with keeping the accident numbers down. When the Col. heard about this accident he went ballistic and poor Emmett was going to have his azz court-martialed. So when the Col. asked Yeager, "Why the hell was Hatch doing a roll down so low?"

    Yeager replied, "All ours pilots do that, we do a roll on final approach to make sure we're not landing on top of somebody else." And so he saved Emmett's career.

    • Yeager replied, "All ours pilots do that, we do a roll on final approach to make sure we're not landing on top of somebody else." And so he saved Emmett's career.

      And Yeager had good reason to say this: airplanes do land on top of each other [telegraph.co.uk], especially when a high-wing plane is doing a low approach and a low-wing plane is doing a steep approach. It's also a somewhat common midair collision scenario, of a high-wing plane climbing into a low-wing plane, because of the same visibility problems inherent in the two designs.

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