Virgin Space crash

[Rodan 0]

philh

Anyone know the highest ever deployment of a canopy? If he deployed anywhere near the 50,000 ft altitude of the accident, maybe thats a record?

This story reminds me a lot of a book I read many years ago:

"The Man Who Rode the Thunder"

http://www.amazon.com/The-Man-Who-Rode-Thunder/dp/0135482712

"An account of a nine mile fall through space, thunder, lightning, rain, hail, made by the author in July, 1950. He reviews the years of professional military training, from joining the Marines in 1940, through boot training, war in the Pacific, graduation to wings, training in jets. It was the culmination of this that made possible his survival of a fantastic 35 minute ordeal, when forced to abandon his Crusader jet at almost 50,000 feet."

[rmarshall234 13]

Yep, great story. William H Rankin is The Man That Rode The Thunder. Although he ejected above 47K ft his automatic opener deployed his canopy at 10K ft. Went for a hell of a ride after that though. The rapid decompression seemed to be one of the biggest problems. I suspect Peter Siebold had a similar experience with rapid decompression. It's amazing that he survived "being blown out of a rocket ship". Sure would like to hear that story over a beer someday.

[ryoder 1,384]

Much more detail than I've seen before: http://www.theguardian.com/science/2014/nov/07/virgin-galactic-tragedy-revealed-spaceshiptwo-disaster

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[Calvin19 0]

ryoder

Much more detail than I've seen before: http://www.theguardian.com/science/2014/nov/07/virgin-galactic-tragedy-revealed-spaceshiptwo-disaster

Good share, lots of new info there. Thank you.

[rmarshall234 13]

Peter Siebold is a really impressive guy. Not a military test pilot, he came up through the civilian ranks. And he's been there since the beginning, making these Space Ship I/II test flights. Now he has this, possibly the most amazing tale of survival in aviation history. My hat is off to that guy.

[pchapman 261]

rmarshall234

Now he has this, possibly the most amazing tale of survival in aviation history. My hat is off to that guy.

Well, unlike Sgt. Nicholas Alkemade (and a few others) he was a bit of a wuss in that he did have the advantage of a parachute on his back. That's ok since he wasn't over deep drifted snow and pine trees.

But yeah, still pretty good bit of luck.

There are some other pretty amazing tales out there.

At 50,000' one has about 11% of sea level pressure. Not quite space but not good for breathing. It would be interesting to figure out what kind of freefall time Siebold might have had. Some part might be faster if still strapped in to a seat or other wreckage.

People have managed to survive ultra low pressures. E.g., "For example, in 1965 a technician inside a vacuum chamber at Johnson Space Center in Houston accidentally depressurized his space suit by disrupting a hose. After 12 to 15 seconds he lost consciousness. He regained it at 27 seconds, after his suit was repressurized to about half that of sea level."

But once past a minute and a half, or maybe 3 minutes, who knows, things get very iffy.
(Ref: Scientific American http://www.scientificamerican.com/article/survival-in-space-unprotected-possible/ )

Still when you wake up it may take some time to become usefully aware and able to take action.

I seem to recall the record for highest intentional civilian skydive without oxygen was de Gayardon at 41,700'.

[Phillbo 11]

The SpaceShipTwo was torn apart when the copilot who died activated a mechanical air braking system at Mach 1. Investigators are now looking into how such an error could occur with a highly trained individual.

http://blogs.discovermagazine.com/lovesick-cyborg/2014/11/08/the-mystery-of-virgin-galactics-pilot-error/

[rmarshall234 13]

Has anyone heard how Peter Siebold is doing? The press report of a "shoulder injury" is a pretty vague description after surviving a catastrophic airframe failure at Mach 1. Wishing him the best.

[cpoxon 0]

pchapman

At 50,000' one has about 11% of sea level pressure. Not quite space but not good for breathing. It would be interesting to figure out what kind of freefall time Siebold might have had. Some part might be faster if still strapped in to a seat or other wreckage.

More detailed account. Seems it was a CYPRES save

Skydiving Fatalities - Cease not to learn 'til thou cease to live

[pchapman 261]

Finally with the NTSB documents there are more facts out there about the accident.

From one of the many docket reports, one called "SURVIVAL FACTORS GROUP CHAIRMAN’S FACTUAL REPORT", it shows the parachuting related items to be:

Butler model HX-500/24 (with the 'Sombrero' slider)

CYPRES 2 Aircrew (with 10' arming lanyard, and set to a minimum 5-7 sec time delay, activation altitude of 13000' at standard pressure curves, and 35 m/s)

The HX-500 has some interesting high speed features in addition to the slider:

Quote

If the speed was high enough (roughly more than 160 knots depending on weight and altitude) the pilot chute tie would break followed by the zip-strip and eventually the pilot chute would disconnect. Otherwise, the pilot chute would remain attached. The parachute was also equipped with a sacrificial “four-leaf” vent cap that was tied together with break cord and was designed to open or blow at high speeds to minimize the opening shock. At low speeds the vent cap would remain closed to increase the pressure inside the canopy and accelerate the inflation.

For Siebold, the vent cap stayed closed and the pilot chute remained attached, consistent with a normal freefall speed activation.

There are plenty of interesting details in the reports, but one issue was that Siebold wasn't able to activate the bailout oxygen. It isn't clear whether he was grabbing the right thing, but he tried multiple times. Because of faulty memory and going in and out of consciousness, he doesn't remember exactly at what stage he was doing that.

There was an issue that the force needed to activate the oxygen bottle could be 40-50 lbs, which can make it tough for a one handed pull. (His right arm was broken in multiple places, including breaking off the head of the humerus. Sounds like wind flail injuries to me, having the arm wrenched over the side of the seat, as military ejectees sometimes have happen.) The handle on the Butler rig resembled a cutaway handle, in a similar position on the rig. Scaled Composites and Butler Parachute Systems had done some work on reducing the pull forces but there were limitations due to the way the bailout bottles are designed.

As for the parachute opening:

Quote

Analysis of the data provided by Airtec engineers indicated that the pilot’s AAD activated at 11,590 feet [9] MSL and that the device’s cutters, which allowed the parachute to release, activated at 10,870 feet MSL. The pilot’s average vertical velocity after the device’s activation and prior to the activation of the cutters was 135 miles per hour (approximately 60 meters/second or 200 feet/second).

[9] The AAD activation would have been triggered by the detachment of the 30 inch yellow lanyard that was affixed to the 10 foot static line connecting the pilot’s parachute to his seat.

It is a little unclear how the numbers match up, given the altitudes, speeds, and AAD timer delays listed above.

But in any case the crucial thing is that Siebold woke up during freefall and undid his seatbelt, freeing himself from the seat, which would also pull the long lanyard attached to the seat to arm the Cypres. He said he did go back unconscious (or not usefully conscious), and so did not pull the ripcord. The next thing he knew he felt opening shock.

The reports make it sound like the 11,590' event was when he separated from the seat and the Cypres was armed. So he wouldn't have had much time to pull the ripcord anyway, as a few seconds later the AAD would fire after a short delay (designed to let a crewmember clear the aircraft and slow down closer to normal freefall speeds).

As for ground elevations, Mojave airport some distance away is at 2800', making the deployment somewhere very roughly around 8000' AGL. Photos from an Extra aerobatic aircraft being used as a chase plane show Siebold descending under the parachute.

The front cockpit section, without any parts of the stub wings, must have hit the ground at high speed based on the descriptions, with the copilot still strapped in his seat. He was the one who unfortunately turned the feather unlocking handles at just after Mach 0.8, forgetting to wait for Mach 1.4 when the forces on the tails wouldn't prematurely cause the actual 'feathering' to take place. The background as to why the error happened is still a little murky to me and would take some discussion so I won't get into that.

[pchapman 261]

I have since read the Aircrew Cypres 2 manual, which is a bit vague but helps understand things a bit.

It does operate differently than a regular Cypres. The Cypres button is just for a ground self test that is a highly recommended procedure but doesn't seem essential for flight. It does not seemingly stay on. It turns on or is "hot" (or "sharp" as used in the manual - probably the original German term) for 14 hours if a velcroed orange cushion is pulled out. Reinserting the cushion and its cable shuts the Cypres off again.

It doesn't actually say what kind of a delay there is after pulling the orange cushion, so I don't know if it matched what the NTSB wrote about, 5-7 seconds, or if it might be less. The static line lanyard on the Butler rig would be set up to pull that Cypres cable to turn it on.

I'm guessing that because it isn't turned on normally before flight, the activation altitude is therefore just 13000' at normal pressure and temperature conditions above sea level, something suggested by the NTSB reports. It wouldn't calibrate itself to that day's conditions or takeoff level.

(And curiously, while the Aircrew AAD still has a 12.5 year limit, maintenance is due only at the 5 and 10 year intervals!)

In the previous post I wrote that based on the NTSB info it makes it sound as if the lanyard were pulled at 11,590' ASL, with the Cypres firing soon after once it had done its activation delay. But the firing at 10,870' doesn't quite match the "5-7 second" delay that's also mentioned.

So an alternative might be to put more weight on some other statements by Siebold, who admits that he drifted in and out of consciousness and couldn't recollect the exact sequence of events. But he felt like he woke up after the breakup, at a high altitude above the desert, and separated himself from the seat then. His next memory was the canopy openin

But what "high altitude" really was is not clear. Was this around 10,000' and the AAD fired just seconds later, or was this up at very high altitude, and he went back unconscious for a long time? I previously suggested the scenario where the lanyard wasn't pulled until near activation altitude, but it is also possible it was pulled at very high altitude.

Either way it was critical that Siebold woke up for a short period of time and thought to release the seatbelt.

[cpoxon 0]

pchapman

Either way it was critical that Siebold woke up for a short period of time and thought to release the seatbelt.

ParabolicArc

Because he considered this a “high-risk” flight he stated that he took extra precautions and took time to think through scenarios that might happen and how he would rapidly respond in an emergency and activate his parachute and oxygen cylinder. About 10-15 minutes prior to release there was a period of low workload when he was able to physically feel for the parachute D-ring rip cord, oxygen activation pud, and the dual-lever seatbelts to improve his “muscle memory” in the event of an emergency. This was not a written procedure, but something he personally did on some flights.

Smart

Skydiving Fatalities - Cease not to learn 'til thou cease to live