Spaceship 2 Mishap

[vontresc]

Sixie, what Henning is tying to tell you is that the shock wave while passing through mach one may have had enough force to overpower the actuator and move the feather into a non locked position resulting in structual failure. This is probably the reason the OPS say not to do it until mach 1.4

 

[Checkout_my_Six]

Sixie, what Henning is tying to tell you is that the shock wave while passing through mach one may have had enough force to overpower the actuator and move the feather into a non locked position resulting in structual failure. This is probably the reason the OPS say not to do it until mach 1.4

Ya, I got that....but there was a mechanical interlock....that opened. Why? Did this flight profile have more energy....more Max Q?....and exceed structural limits?

was it a mechanical failure?

was it an uncommanded feather event?...and what are the causalities for those?


we just don't know.....

 

[ClimbnSink]

I got the impression there was in cockpit video or audio of one of the pilots unlocking the feather early. But I don't know, again I'm surprised at how fast they know it was an early interlock release, live streaming cameras and telemetry would prove that. If that exists or not I have no idea.

 

[3393RP]

I got the impression there was in cockpit video or audio of one of the pilots unlocking the feather early. But I don't know, again I'm surprised at how fast they know it was an early interlock release, live streaming cameras and telemetry would prove that. If that exists or not I have no idea.

There were four cameras in the cockpit and over a thousand telemetry channels on the craft.

This morning I read an article that said the video showed him unlocking the system, then quickly moving to try and relock it as if he had made a mistake. I can't find the article to link it.

By the way, the feather system is pneumatic. I don't know if the activation is via a manual valve or an electromechanical interface.

 

[wanttaja]

9 sec. after ignition of the hybrid rocket, the mechanism that controls the stowage of the moving tails moved from "lock" to "unlock." Two actions are required to "feather". The lock was not to be moved until mach 1.4....but was moved early at mach 1.0.

Hmmm. Was there checklist/test sheet instruction to move the lever when speed reached mach 1.4? It seems rather strange that you'd bother to unlock the tails while still in powered flight. Why wouldn't you wait until you were coasting?

We may be getting mixed up by the wording of the NTSB announcement. *Was* the co-pilot supposed to activate the lever at mach 1.4? Or is that just a statement of the minimum speed it should be activated, and the lever wasn't scheduled to be moved until much later?

Ron Wanttaja

 

[vontresc]

Hmmm. Was there checklist/test sheet instruction to move the lever when speed reached mach 1.4? It seems rather strange that you'd bother to unlock the tails while still in powered flight. Why wouldn't you wait until you were coasting?

We may be getting mixed up by the wording of the NTSB announcement. *Was* the co-pilot supposed to activate the lever at mach 1.4? Or is that just a statement of the minimum speed it should be activated, and the lever shouldn't have been moved at all?

Ron Wanttaja

My thoughts exactly... A DB Cooper Vane style safety lock would probably work...

 

[Henning]

Ya, I got that....but there was a mechanical interlock....that opened. Why? Did this flight profile have more energy....more Max Q?....and exceed structural limits?

was it a mechanical failure?

was it an uncommanded feather event?...and what are the causalities for those?


we just don't know.....

What mechanical interlock? What is the actuation process?

 

[3393RP]

well....we don't yet know if this system worked as intended. It might not have.....

Could be something with the sampling rate for that lever, an improper code initialization....who knows what went haywire?...and caused the actuation of the feathers.

The unlock command certainly did work as intended because the feathering system deployed after being unlocked. If it had not been unlocked then the booms could not have deployed.

You are muddling the unlock command with a deployment command with speculation about resonance, sampling rates, software, etc.

Not only that, the fact the co-pilot moved the lever contrary to the test card is ample evidence that high EAS, q_Max and transonic loads were likely responsible for the breakup.

The deployment system had worked without incident on previous flights. Your suppositions are highly unlikely given the fact of improper controls manipulation by the crew.

 

[Checkout_my_Six]

nope....two actions are required to "feather". Only one action was performed.

It was an "uncommanded feather".....go back and listen to the man.

 

[N801BH]

nope....two actions are required to "feather". Only one action was performed.

Obviously a system failure...

 

[Velocity173]

NTSB already said they suspect pilot error. The in cockpit video shows the Copilot releasing the lock to feather the wings. I couldn't imagine that being part of the test card. In the old Space Ship 1 Discovery documentary I never saw any test where they feathered while the engine was running. It was always after shutdown and near apogee.

 

[3393RP]

nope....two actions are required to "feather". Only one action was performed.

It was an "uncommanded feather".....go back and listen to the man.

Sigh...

The unlock command allows the booms to move, regardless of whether this happens via the pneumatic deployment system or from external forces.

Since the video clearly shows the unlock command was performed, it's obvious the lock/unlock system worked as designed.

That is the point I am making. For you to dispute that the unlock command did not perform as designed is silly...the fact the booms moved is proof they were unlocked as the lever movement intended.

We then move to the deployment. You speculate it was some ghost in the machine, a spurious phantom signal, even though the unlock command was improperly initiated at the most perilous portion of the flight envelope, the transonic/q_Max regime.

The most obvious and likely correct cause was the huge dynamic pressures associated with the fact the deployment occurred at Mach 1.0, and at a EAS of over 250 kts.

The air loads on the boom system had only to overcome the holding action of the pneumatic cylinders, and we don't even know if they were pressurized on both sides of the ram. The flight loads at 45,000' and over 250 kts EAS could easily have caused the deployment.

I find that much more likely than your fishing for some cause that probably wasn't even present in the systems considering the design philosophy.

Just to give an example of how extreme this regime was, consider that SpaceShipOne boom deployment occurred at an EAS of less than 16 kts. when the craft was at apogee.

 

[PaulS]

Sigh...

The unlock command allows the booms to move, regardless of whether this happens via the pneumatic deployment system or from external forces.

Since the video clearly shows the unlock command was performed, it's obvious the lock/unlock system worked as designed.

That is the point I am making. For you to dispute that the unlock command did not perform as designed is silly...the fact the booms moved is proof they were unlocked as the lever movement intended.

We then move to the deployment. You speculate it was some ghost in the machine, a spurious phantom signal, even though the unlock command was improperly initiated at the most perilous portion of the flight envelope, the transonic/q_Max regime.

The most obvious and likely correct cause was the huge dynamic pressures associated with the fact the deployment occurred at Mach 1.0, and at a EAS of over 250 kts.

Just to give an example of how extreme this regime was, consider that SpaceShipOne boom deployment occurred at an EAS of less than 16 kts. when the craft was at apogee.

Whatever the reason, it's a crappy design, if it is that critical not to deploy early it should have a more fail safe method of deploying. I'm willing to bet that it hadn't been considered that it would deploy with out being actuated.

 

[ClimbnSink]

Whatever the reason, it's a crappy design, if it is that critical not to deploy early it should have a more fail safe method of deploying. I'm willing to bet that it hadn't been considered that it would deploy with out being actuated.

Yes and we should safety wire the mixture rich on GA planes for the same reason. You build something cool, like I dunno a private spaceship, there is probably going to be a way for the pilots to crash it.

 

[RyanShort1]

Whatever the reason, it's a crappy design, if it is that critical not to deploy early it should have a more fail safe method of deploying. I'm willing to bet that it hadn't been considered that it would deploy with out being actuated.

I wouldn't say so. Remember, it's still in testing phase and my guess is that no one anticipated a pilot flubbing up and unlocking it too early. Crappy that does not make it.

 

[Checkout_my_Six]

Obviously a system failure...

yup....obviously.

 

[3393RP]

Whatever the reason, it's a crappy design, if it is that critical not to deploy early it should have a more fail safe method of deploying. I'm willing to bet that it hadn't been considered that it would deploy with out being actuated.

It likely hadn't been considered the co-pilot would perform an action which could cause loss of the vehicle when performed at Mach 1 and q_Max.

How "fail safe" should a test vehicle design be? There has to be a limit to such nonsense in flight test. As I said earlier, that's why highly educated and skilled crew fly such craft.

 

[PaulS]

Yes and we should safety wire the mixture rich on GA planes for the same reason. You build something cool, like I dunno a private spaceship, there is probably going to be a way for the pilots to crash it.

I didn't know GA aircraft self destruct moments after incorrectly setting the mixture.

I don't know, maybe an interlock gated to a speed indicator for this device is warranted, the interlock could have a manual override if it fails. One of the few truths in life is that people will screw up, especially when in a very high stress situation like flying space ship. An engineer should anticipate these potential situations where the craft will self destruct a few seconds after a lever is moved at an inappropriate time and build some safety into the design. Never time to do it right, always time to do it over...

 

[PaulS]

I wouldn't say so. Remember, it's still in testing phase and my guess is that no one anticipated a pilot flubbing up and unlocking it too early. Crappy that does not make it.

I think you are probably right, I bet it will be impossible to screw this up on the next flight. I still think someone should have figured this could be a problem.

 

[kyleb]

I think you are probably right, I bet it will be impossible to screw this up on the next flight. I still think someone should have figured this could be a problem.

Same as nobody figured out that 3 pilots sitting in a cockpit could have a ramp strike in SFO or ride down a fully stalled Airbus from 35k'.

There is always a way for the pilot to screw it up.

 

[PaulS]

Same as nobody figured out that 3 pilots sitting in a cockpit could have a ramp strike in SFO or ride down a fully stalled Airbus from 35k'.

There is always a way for the pilot to screw it up.

I hear you, but I think at least the stall to crash from 35k is not the same as pulling a lever a few moments early and having the ship self destruct.

 

[ClimbnSink]

I didn't know GA aircraft self destruct moments after incorrectly setting the mixture.

You can use it incorrectly inflight and shut off the motor, same as unlocking the feathers at the wrong time. You can't always have control and fail-safe at the same time.

 

[N801BH]

Same as nobody figured out that 3 pilots sitting in a cockpit could have a ramp strike in SFO or ride down a fully stalled Airbus from 35k'.

There is always a way for the pilot to screw it up.

I think there were 4 qualified pilots in that cockpit.. Which makes it even worse...

Let's see..

Capt Sum Ting Wong
Capt We Tu Lo
Capt Hol E Fuc
Capt Bing Dang Ow

 

[Henning]

Yes and we should safety wire the mixture rich on GA planes for the same reason. You build something cool, like I dunno a private spaceship, there is probably going to be a way for the pilots to crash it.

Of course, that is why aviation goes through Experimental phase testing to find deficiencies in design, both technical and human interface, and correct them before certification for commercial operations. Remember, this operation needs to be insurable. As for correcting this deficiency, not a big problem.

 

[Velocity173]

Not a flaw in the design. Not a glitch. The video shows the pilot feathered the aircraft too soon. Only question now remains, why?

 

[Henning]

You can use it incorrectly inflight and shut off the motor, same as unlocking the feathers at the wrong time. You can't always have control and fail-safe at the same time.

Oh yes you can, the only question is which has over riding authority.

 

[Henning]

Not a flaw in the design. Not a glitch. The video shows the pilot feathered the aircraft too soon. Only question now remains, why?

Which one survived?

 

[ClimbnSink]

Not a flaw in the design. Not a glitch. The video shows the pilot feathered the aircraft too soon. Only question now remains, why?

Yup. And if one of those guys can make such a simple mistake what chance do we hobby pilots have?

 

[N801BH]

Which one survived?

The one who didn't feather...

 

[PaulS]

Yup. And if one of those guys can make such a simple mistake what chance do we hobby pilots have?

Greg, our planes do not fall out of the sky if you lean too aggressively and the engine stalls...... not the same.

 

[Velocity173]

The one who didn't feather...

Correct. Pete Siebold. The PIC.

 

[ClimbnSink]

Greg, our planes do not fall out of the sky if you lean too aggressively and the engine stalls...... not the same.

There are things you have control over in your plane that can break your plane. Same as SS2.

 

[PaulS]

There are things you have control over in your plane that can break your plane. Same as SS2.

What lever that you actuate in your plane then immediately reverse will cause it to break up in flight?

 

[3393RP]

There are things you have control over in your plane that can break your plane. Same as SS2.

What lever that you actuate in your plane then immediately reverse will cause it to break up in flight?

The point being misoperation is possible in all things human, not that they will immediately destruct when this happens. When it does occur in a vehicle built to perform to the 99.9 percentile the margins are necessarily lessened.

 

[ClimbnSink]

What lever that you actuate in your plane then immediately reverse will cause it to break up in flight?

Full control deflection above VA. There are lots of ways to kill yourself by pulling the wrong lever in little airplanes. None of them as dramatic as spaceship crashes but we end up just as dead.

 

[Henning]

There are things you have control over in your plane that can break your plane. Same as SS2.

No, mixture does not break the plane, it turns off the engine, yo become a glider, you push the handle back in, you have an engine running in a perfectly fine aircraft.

 

[ClimbnSink]

No, mixture does not break the plane, it turns off the engine, yo become a glider, you push the handle back in, you have an engine running in a perfectly fine aircraft.

Stupid little levers moved at the wrong time kills pilots. As I said not as dramatic as crashing a spaceship. Of course none of us would ever be so daft as to unlock the feathers below mach 1.4.

 

[Henning]

Stupid little levers moved at the wrong time kills pilots. As I said not as dramatic as crashing a spaceship. Of course none of us would ever be so daft as to unlock the feathers below mach 1.4.

That's the point, the mistake can be made, for commercial certification that will require some form of interlock to prevent a repeat occurrence.

 

[wanttaja]

NTSB already said they suspect pilot error. The in cockpit video shows the Copilot releasing the lock to feather the wings. I couldn't imagine that being part of the test card.

Again, do we have any confirmation that the test card or checklist included unlocking the wings at that point of the flight? The NTSB announcement implies that the action was performed slightly prematurely (activated at Mach 1, instead of Mach 1.4) but it seems to me (and to others) that the unlock action shouldn't have been anywhere near that phase of flight.

If it was part of the test card, but performed slightly early, it points to a misread mach meter or a momentary lapse on behalf of the co-pilot.

But if it *wasn't* on the test card... you have to wonder what the co-pilot was thinking. Is that lever similar to another? Could he have accidentally activated it in lieu of another control?

What are the command procedures used by Scaled? Are they command-response (Pilot: Activate feather unlock. Co-Pilot: Feather is unlocked) or is each pilot executing his own checklist independently?

Going to be an interesting accident report.

Ron Wanttaja

 

[wanttaja]

That's the point, the mistake can be made, for commercial certification that will require some form of interlock to prevent a repeat occurrence.

Ummmm.... ARE there standards for commercial certification of privately-owned man-carrying spacecraft? If there aren't, then no one can force Galactic to add an interlock. It's my understanding that the FAA has waived all the normal certification rules. Without a regulatory basis, the FAA can't tell Virgin to modify their design.

But maybe the FAA has put something in place. Anybody got a link?

Ron Wanttaja