News Virgin Galactic SpaceShipTwo accident during powered test flight

[RGClark]

Some other problems with the flight procedure become apparent from the video I posted in post #150. During that flight in September, 2013, the feathering was unlocked at about 16 seconds into the engine burn, and the feathering deployed correctly only later after engine cutoff.

But in the failed flight the catastrophic unlocking occurred only 9 seconds into the engine burn. That leaves a scant less than 7 second window to perform this action of unlocking that will lead to mission success or complete destruction of the vehicle. It's very disconcerting to know this would be the procedure as well for the passenger carrying flights.

Another key problem from listening to the video is that the pilots are not calling out the speed and altitude during the burn. The only time they call out the altitude is a few seconds after the engine cutoff when they are close to max altitude. Note that when landing jet airliners when speed and altitude are both critical to a safe landing the pilots are calling these out to ensure they are within the correct range. The SS2 pilots should also be calling out both speed and altitude during the engine burn to insure this mission critical step of the unlocking is done only at the right time.

Bob Clark

 

[pattersonlee]

That was my point. Mission success depends entirely on a human to flip a switch within a 7 second period of time when they are pinned back in the seat of a rocket powered vehicle under power.

What does that pilot watch to determine when to flip the non-fatal/fatal switch, a speed indicator.

I just can not imagine that is the design and limits of safety/success/failure they implemented.

It's more like a crap shoot than engineering.

 

[llarian]

"Engineering" has had a lot of successful crap shoots. "Engineering" has also had a lot of "not successful" crap shoots.

 

[statickid]

7 Seconds is a long time. Every common driver faces death and catastrophic vehicle failure every time they approach a stop light. What if you waited 7 seconds before applying the brakes after seeing a traffic light turn red? What if you waited 3 seconds? 16 seconds?

 

[C3PO]

Not to mention the amount of possible mistakes pilots can make during a bad weather landing that can have fatal consequences. Calling the engineering a "crap shoot" when the investigation is barely underway is not in any way productive. This is why we have the NTSB (AIB in my case). They will draw the conclusions once they have done the analysis', and then make recommendations if there's something that needs to change.

This was still a test flight and if this particular craft hadn't crashed and went on into service, there would have been changes made to it before passengers would fly on it. Scaled still have some research to do before entering service, and this test flight was a part of that. Test pilots earn their money by flying "outside the envelope". You can't equate a passenger flight and a test flight like this. Test pilots do things that would never be accepted on a passenger flight.

The NTSB may recommend some changes to the feather mechanism or maybe they don't. We have to wait for the analysis of this accident to be completed before we make judgments about the engineering.

 

[Donamy]

7 Seconds is a long time. Every common driver faces death and catastrophic vehicle failure every time they approach a stop light. What if you waited 7 seconds before applying the brakes after seeing a traffic light turn red? What if you waited 3 seconds? 16 seconds?

Depends on how fast I was going, and how far away.

 

[n122vu]

7 Seconds is a long time. Every common driver faces death and catastrophic vehicle failure every time they approach a stop light. What if you waited 7 seconds before applying the brakes after seeing a traffic light turn red? What if you waited 3 seconds? 16 seconds?

What if you were first in line at the light at a busy intersection and hit the accelerator 7 seconds before it turned green?

 

[Urwumpe]

More important is the question there: Can a mechanism do this really better and more reliable?

 

[C3PO]

More important is the question there: Can a mechanism do this really better and more reliable?

And that's one of the things the NTSB is going to look at. Remember that EVERY engineering decision is some kind of compromise, and only hindsight can tell if it was the correct one. Real life hasn't got a cheat-sheet! Only a lot of differing opinions.

 

[RGClark]

7 Seconds is a long time. Every common driver faces death and catastrophic vehicle failure every time they approach a stop light. What if you waited 7 seconds before applying the brakes after seeing a traffic light turn red? What if you waited 3 seconds? 16 seconds?

Actually, it's less than a 7 second time window in the SS2 flight, since the 9 second unlocking was too soon. Perhaps the time window is only 3 to 4 seconds wide.
In the stop light case thousands if not millions of people every year don't make that decision in the needed time frame, many times with fatal results. That is also a reason why there are yellow lights.

But actually I'm inclined to think the pilots were not apprised of the fact there would be catastrophic results by unlocking early. It's possible Scaled Composites was not aware of this as well.

Bob Clark

 

[rhoude57]

As Bob states, the SS2 pilots probably assumed the feather actuators were strong enough to keep the feathers n the horizontal position. I'm sure the NTSB want to have a close look at them to figure out what happened.

 

[Thunder Chicken]

Another consideration, these guys were flying a new engine. That would be some incentive to maybe be proactive (maybe too proactive) on enabling abort capability.

Does anybody know anything about Peter Siebold's condition? Here's hoping he's recovering OK.

 

[pattersonlee]

Seibold is home from the hospital. Goggle latest news for him and you get an interesting interview with him and his father. He blacked out from the altitude and came to decending on his chute. The launch plane circled him and he was alert enough to give them a thumbs up. Incredible story.

Has not spoken to NTSB yet.

 

[Thunder Chicken]

Peter Siebold is actually recovering at home. :thumbup:

http://www.nydailynews.com/news/national/virgin-galactic-spaceshiptwo-survivor-miracle-article-1.2004352

It sounds like he has potential for a full recovery.

 

[ADSWNJ]

Thumbs-up to a chase plane as he was falling back to Earth:

http://www.dailymail.co.uk/sciencet...pace-pilot-came-way-gave-thumbs-say-m-OK.html

It's so sad for the families of both the test pilots. That gnawing feeling of why did one survive and the other didn't must be immense the deal with, regardless of which family.

 

[Andy44]

Thumbs-up to a chase plane as he was falling back to Earth:

http://www.dailymail.co.uk/sciencet...pace-pilot-came-way-gave-thumbs-say-m-OK.html

It's so sad for the families of both the test pilots. That gnawing feeling of why did one survive and the other didn't must be immense the deal with, regardless of which family.

According to that article Siebold still had the base of his seat strapped to him, which I guess means the seat back got loose. That's probably why his chute worked and Alsbury's didn't since he was strapped to his seat when they found his body.

It also says his eyes haven't recovered from being exposed to -60 deg air, yikes! Lucky to be alive.

On a side note, the commenters on that article are strangely obessesed with the pay scales for VG test pilots...but that's what I get for reading online comments.

 

[Frilock]

According to that article Siebold still had the base of his seat strapped to him, which I guess means the seat back got loose. That's probably why his chute worked and Alsbury's didn't since he was strapped to his seat when they found his body.

It also says his eyes haven't recovered from being exposed to -60 deg air, yikes! Lucky to be alive.

On a side note, the commenters on that article are strangely obessesed with the pay scales for VG test pilots...but that's what I get for reading online comments.

Scary, scary place the interwebs be.

 

[Proximus]

Could SS2 survive it's proposed flight plan (with paying customers aboard) if the feathers were to remain locked after apogee?
Basically if it was to remain in accent mode?

 

[C3PO]

Could SS2 survive it's proposed flight plan (with paying customers aboard) if the feathers were to remain locked after apogee?
Basically if it was to remain in accent mode?

That's very unlikely. If that was the case there is no reason to have them. The 'feathers' change the aerodynamically stable attitude to "bottom-forward" and that helps slow the craft before it reaches the dense air at lower altitude. If the craft reaches denser air on a pure ballistic track, the high angle + velocity would most likely mean a similar outcome as the last flight.

 

[Proximus]

It's a difficult situation for Virgin to have a vehicle so far along its design pipeline to suffer such a tragic accident.