News Virgin Galactic SpaceShipTwo accident during powered test flight

[Linguofreak]

I've been thinking about this particular point a lot today. Does it count as a "successful bail out" when the ship simply disintegrates around you?

And I've been wondering whether this really counts as a spacecraft accident, as everybody keeps saying. Given that the vehicle is not capable of reaching orbit, regardless of its zoom climb capabilities has never left the atmosphere, and was not scheduled to leave the atmosphere on this flight, this really strikes me as more of a mundane aircraft accident (to the extent that accidents with fatalities are ever "mundane").

All that engineering work that went into Apollo-style LES towers that (thankfully) never needed to be used, and the first successful ejection required no real planning at all other than equipping the pilots with parachutes that automatically open.

Those Apollo-style LES towers *did* need to be used. Unfortunately, on January 28th of 1986, we were flying the STS stack instead of Apollo++ on a Saturn IB derivative, and the LES tower was unavailable.

 

[statickid]

It saved lives once.
Only thing they had to worry about in the capsule is to switch off the CVR for modesty's sake.
Soyuz Launch Escape Tower System - YouTube

That guy in the middle... scratching the back of his neck :lol:

KEEP IT TOGETHER MAN!!

on a different note, that looks like one heck of a chest-crushing mega-G escape!

---------- Post added at 08:53 AM ---------- Previous post was at 08:34 AM ----------

And I've been wondering whether this really counts as a spacecraft accident, as everybody keeps saying. Given that the vehicle is not capable of reaching orbit, regardless of its zoom climb capabilities has never left the atmosphere, and was not scheduled to leave the atmosphere on this flight, this really strikes me as more of a mundane aircraft accident (to the extent that accidents with fatalities are ever "mundane").



Those Apollo-style LES towers *did* need to be used. Unfortunately, on January 28th of 1986, we were flying the STS stack instead of Apollo++ on a Saturn IB derivative, and the LES tower was unavailable.

just found this interesting article:

http://www.space.com/6564-edge-space.html

 

[Quick_Nick]

From NTSB on Twitter:
" …the copilot, who was in right seat, moved the lock/unlock handle into unlock position; he did not survive accident."
I don't know why Hart redacted that assessment at the briefing. (not that it matters)
So ignore what was thought to be the most important part of the final media briefing. Hart apparently did not speak in error originally, though yesterday seemed to have thought he did.

 

[C3PO]

Maybe there was a slight doubt about the accuracy of the statement, and that's why they retracted it. But later they confirmed it.

 

[garyw]

Presumably, the time Mach 1.4 is reached, SS2 has already gained altitude, where the air is subsequently thinner, and it is past the maximum aerodynamic loads on the ascent, so switching to a feather configuration is safe.

AFAIK, the booms are feathered at apogee, after a coast from MECO.

This is my understanding as well, at Mach 1.4 SS2 would be around 75,000 to 80,000ft. I do suspect that wind forces acting on the boom caused the boom to break whatever was holding it in place once the mechanical locks were released.

 

[C3PO]

This is my understanding as well, at Mach 1.4 SS2 would be around 75,000 to 80,000ft. I do suspect that wind forces acting on the boom caused the boom to break whatever was holding it in place once the mechanical locks were released.

:hesaid:
The checklist stated that the locks shouldn't be released below Mach 1.4. I'm guessing that the actuators were overcome by aerodynamic forces once the locks were released.
We don't have enough (public) data yet to make any assumption abut the reason for the early release, but the forming of the 'Human Performance Group' indicates that they could looking at pilot error possibly linked to displays that can be misinterpreted. It's very much a (read: my) subjective opinion and not really built on anything else but the feeling I got during the last press conference.

 

[Andy44]

And I've been wondering whether this really counts as a spacecraft accident, as everybody keeps saying. Given that the vehicle is not capable of reaching orbit, regardless of its zoom climb capabilities has never left the atmosphere, and was not scheduled to leave the atmosphere on this flight, this really strikes me as more of a mundane aircraft accident (to the extent that accidents with fatalities are ever "mundane").

Well, if Apollo 1 counts than so does this. At least this one was flying under power...

 

[C3PO]

And the name of the craft is SpaceShip2!

 

[rhoude57]

If the feathers were allowed to go to the unlocked condition while in a flight condition under which it was clearly unsafe to do so, I would see that as a major failure of the SpaceShipTwo safety analysis process.

 

[C3PO]

If the feathers were allowed to go to the unlocked condition while in a flight condition under which it was clearly unsafe to do so, I would see that as a major failure of the SpaceShipTwo safety analysis process.

Remember that we're talking about a prototype here. Adding a system to prevent premature unlocking adds complexity and (at least) one more thing that can fail. Imagine not being able to deploy the feather because the safety system has jammed. When you add safety systems you run the risk of creating new problems. Not to mention weight, which is every spacecraft's worst enemy.

Regular aircraft don't have any system to prevent flap deployment at high speeds. They do have systems to prevent spoiler deployment during flight, and our local airline lost a [ame="http://en.wikipedia.org/wiki/Atlantic_Airways_Flight_670"]BAe 146[/ame] when that system failed.

A better option IMHO is to provide pilots with reliable readouts that shows when it's safe to unlock the feather mechanism. In this accident we know that the crew unlocked the feather early, so the question here is what lead them to take that action. That's why I believe that the NTSB is going to spend quite some time investigating the display system on SS2.

 

[Thunder Chicken]

Remember that we're talking about a prototype here. Adding a system to prevent premature unlocking adds complexity and (at least) one more thing that can fail. Imagine not being able to deploy the feather because the safety system has jammed. When you add safety systems you run the risk of creating new problems. Not to mention weight, which is every spacecraft's worst enemy.

Also, along the vein of it being a prototype air/spacecraft, the test pilots are expected to know the systems and are generally allowed more control authority than would be found in a production vehicle, even if that authority might endanger the vehicle if utilized improperly or at the wrong time. You don't want to be caught in a corner of the test flight envelope and not have control.

As for this situation, I don't know what to suggest as a completely fool-proof safety system for the feather. If it deploys during powered flight - loss of vehicle and crew. If it *fails* to deploy on re-entry - loss of vehicle and crew. Any sort of safety interlock for this cannot have a default failure mode (e.g. when in doubt or broken, feather (or not)). It is like the Apollo LEM ascent stage - it simply must work without fail. That's a tall order even for simple mechanisms.

---------- Post added at 07:34 PM ---------- Previous post was at 07:11 PM ----------

It seems rather strange that there is so much question about who was pilot or co-pilot. In every winged aircraft I've flown, the pilot in command sits in the left seat, co-pilot in the right seat. Is the confusion in which seats the pilot or copilot were sitting, or who was actually pilot or copilot (they couldn't identify the individuals in the left/right seats from the video)?

In the shuttle they used pilot/commander crew assignments such that the "pilot" is in the right seat, "commander" in the left seat, but in essence the roles are the same - commander = pilot in command, pilot = assistant pilot or copilot.

 

[pattersonlee]

At the end of the briefing, they ran a correction that said "the co-pilot seated in the right seat actuated the lock/unlock lever. And that the co-pilot did not survive the crash." So I think the NTSB confused themself and they in fact do know who unlock the feather.

Does anyone know if the locking mechanism is a physical latch-type of arrangement or is it just an electrical lock-out of the actuators?

Finally, do you interpret the NTSB statement that the feather fully deployed or was only starting to move into a feather position. Does anyone know at what velocity and altitude the feather remains in the cocked position on reentry? Wouldn't forces be similar to the test scenario?

 

[Quick_Nick]

Finally, do you interpret the NTSB statement that the feather fully deployed or was only starting to move into a feather position.

That certainly wasn't clear from the briefings. But my gut says it would have started pitching out of control well before the feathers could reach full deployment. Further, the feathers seem to have ripped off, so perhaps they didn't reach full extension before detaching. I don't know how long they normally take to deploy. There's only a two second window for them to have moved.

 

[pattersonlee]

The correction on the statement of the co-pilot appears as a text statement after the briefing and the Q&A. the You Tube video of a previous launch shows the feather movement to take a about 3-4 seconds to fully articulate.

 

[Kyle]

Finally, do you interpret the NTSB statement that the feather fully deployed or was only starting to move into a feather position.

It wasn't fully deployed, from the activation of the "unlock" switch to the feather's being deployed and the vehicle being destroyed was 2 seconds, which isn't enough time to reach the fully deploy the feathers.

 

[rhoude57]

Remember that we're talking about a prototype here. Adding a system to prevent premature unlocking adds complexity and (at least) one more thing that can fail. Imagine not being able to deploy the feather because the safety system has jammed. When you add safety systems you run the risk of creating new problems. Not to mention weight, which is every spacecraft's worst enemy.

Regular aircraft don't have any system to prevent flap deployment at high speeds. They do have systems to prevent spoiler deployment during flight, and our local airline lost a BAe 146 when that system failed.

A better option IMHO is to provide pilots with reliable readouts that shows when it's safe to unlock the feather mechanism. In this accident we know that the crew unlocked the feather early, so the question here is what lead them to take that action. That's why I believe that the NTSB is going to spend quite some time investigating the display system on SS2.

This "prototype", as you call it, was meant to take on passengers within a year. When it comes to lifes, you add the complexity you need to add to keep those lifes safe... and twice as true when you are flying passengers that have some expecrations of making it back home in one piece and healthy. Point final!
This possible serious safety flaw is even more disturbing when you know the craft was in the hands of Top Gun test pilots.I dread to think what other dangerous stunts your average Joe Blow space cadet could pull on that craft.

---------- Post added at 05:29 AM ---------- Previous post was at 05:25 AM ----------

Also, along the vein of it being a prototype air/spacecraft, the test pilots are expected to know the systems and are generally allowed more control authority than would be found in a production vehicle, even if that authority might endanger the vehicle if utilized improperly or at the wrong time. You don't want to be caught in a corner of the test flight envelope and not have control.

As for this situation, I don't know what to suggest as a completely fool-proof safety system for the feather. If it deploys during powered flight - loss of vehicle and crew. If it *fails* to deploy on re-entry - loss of vehicle and crew. Any sort of safety interlock for this cannot have a default failure mode (e.g. when in doubt or broken, feather (or not)). It is like the Apollo LEM ascent stage - it simply must work without fail. That's a tall order even for simple mechanisms.

---------- Post added at 07:34 PM ---------- Previous post was at 07:11 PM ----------

It seems rather strange that there is so much question about who was pilot or co-pilot. In every winged aircraft I've flown, the pilot in command sits in the left seat, co-pilot in the right seat. Is the confusion in which seats the pilot or copilot were sitting, or who was actually pilot or copilot (they couldn't identify the individuals in the left/right seats from the video)?

In the shuttle they used pilot/commander crew assignments such that the "pilot" is in the right seat, "commander" in the left seat, but in essence the roles are the same - commander = pilot in command, pilot = assistant pilot or copilot.

That's what a properly conducted Safety Analysis program is meant to achieve: safe spacecraft and systems designs and safety mechanisms that minimize the risk of failure while not inducing others.

 

[Keatah]

"Top Gun" test pilots?? I don't think so. And they were NOT stunting around.

 

[PhantomCruiser]

I've known many, many pilots while I was an airedale, several went to the Test Pilot School at Pax River (where I met most of them), several went to Fighter Weapons School (mostly known as Top Gun).

None of them ever screwed around. They might be able to pound beer and booze run like a frat boy in heat in their off time, but they were all business in the cockpit.

Of all of them, I only know of one (and I worked for this guy, he was really pretty cool), but he never would get to be a LtCdr because of a drunken golf cart incident while on a deployment to AUTEC. He was a heck of a pilot too.

 

[Evil_Onyx]

It seems rather strange that there is so much question about who was pilot or co-pilot. In every winged aircraft I've flown, the pilot in command sits in the left seat, co-pilot in the right seat. Is the confusion in which seats the pilot or copilot were sitting, or who was actually pilot or copilot (they couldn't identify the individuals in the left/right seats from the video)?

In the shuttle they used pilot/commander crew assignments such that the "pilot" is in the right seat, "commander" in the left seat, but in essence the roles are the same - commander = pilot in command, pilot = assistant pilot or copilot.

It has been discussed on this forum about pilot/co-pilot seating, There is no rule that the pilot in command sits in the left or right seat, it is a hang over from the first airlines training practices. It is a common practice to stick to left seat Pilot in command as it makes training crews easier, which is why most aircraft instruments are set up to give the pilot in the left as much info as possible (within budgetary and technical limits).

 

[rhoude57]

It has been discussed on this forum about pilot/co-pilot seating, There is no rule that the pilot in command sits in the left or right seat, it is a hang over from the first airlines training practices. It is a common practice to stick to left seat Pilot in command as it makes training crews easier, which is why most aircraft instruments are set up to give the pilot in the left as much info as possible (within budgetary and technical limits).

Also, when all fails, and you are down to essential equipment, the right seat equipment is sacrificed and left seat equipment is that which remains in control and powered from emergency power, if necessary.