Virgin Galactic Executive Summary of Submission on SpaceShipTwo Accident

http://www.parabolicarc.com/2015/07/28/ntsb-executive-summary-spaceshiptwo-accident/

by aerocapture • 11 years ago

79 37 11 years ago

"When accomplished at 1.4 Mach or greater (as required per the SpaceShipTwo checklist procedures and the PF-04 test card) the feather system remained retracted due to a sufficient closing pre-load from the feather actuators and favorable, tail-down aerodynamic loads."
"On normal rocket-powered flights, checklist procedures called for this step to occur after rocket motor burn out while in space just prior to apogee."

I still haven't seen any information on exactly why this particular flight test card called for actuating the feather mechanism at some time other than apogee. Were they trying to test the flying qualities while feathered at a particular dynamic pressure? It doesn't make any sense for the copilot to move the unlock lever while the aircraft was still accelerating unless the test card called for it. And if it did, then did the engineers and test planners fail to take this possible failure mode into account before the flight?

erobbins• 11 years ago

The feather is always unlocked during ascent, in order to make sure the unlock mechanism works. If the unlock mechanism fails at apogee, the ship will not be able to decelerate appropriately and will overspeed and break up in reentry.

robertfw• 11 years ago

The full transcripts were posted on the nasa spaceflight forum here: http://forum.nasaspaceflight.com/index.php?topic=35974.440. One user provided the following summary:

There was corporate conversational knowledge that unlocking the feather system during the transonic region would be catastrophic, but this knowledge wasn't formalized into the pilot handbook or in training. There was formal knowledge that unlocking late would lead to a flight abort, and a recent event had occurred where the unlock was late. Add to this copilot workload increases between flights, the fact that training wasn't done in the suits and equipment worn on the real flight or under the g and vibration loads in the flight, and the result was the copilot unlocked the feather early leading to the loss of the vehicle. As usual, not a single failure, but a chain of smaller failures - lack of formalization of knowledge, lack of training in the operational environment, recent events, pressure to avoid an abort, and you get an overcompensation.

narrator• 11 years ago

They should just do all this in software. Anything that that's complex and life or death should be autopilot driven.

Dylan16807• 11 years ago

And then you get an autopilot that under abnormal conditions doesn't realize it should deploy the parachute...

evanb• 11 years ago

99 Percent Invisible just had some interesting episodes on automation and autopilot, especially as it relates to air travel:

    http://99percentinvisible.org/episode/children-of-the-magenta-automation-paradox-pt-1/

and self-driving cars:

    http://99percentinvisible.org/episode/johnnycab-automation-paradox-pt-2/

tomswartz07• 11 years ago

Anything that that's complex and life or death should be autopilot driven.

What's your stance on autopilot driven cars and trucks?

Arguably, roadway accidents far, far outnumber the number per-capita of space accidents.

zapt02• 11 years ago

A little OT, but the contrast between SpaceX and The Spaceship Company is striking. Elon Musk is pushing for interstellar travel, while Branson is pushing for space tourism. Seems so petty in comparison.

nesyt• 11 years ago

Maybe space tourism increases public interest in interstellar travel?

georgemcbay• 11 years ago

Extremely likely due to the overview effect.

https://en.wikipedia.org/wiki/Overview_effect

pyre• 11 years ago

If Branson is able to make space flight mundane (b/c so many people do it) and/or put "a resort on the moon," I can't see how that wouldn't push things forward.

guelo2• 11 years ago

I don't really follow SpaceX to know what Elon Musk is pushing for, but as a practical engineer it seems unlikely that he would be pushing for something that is outside the realm of what physics considers at all possible.

djloche• 11 years ago

SpaceX has a current mission of reducing launch costs and providing low-cost launch services, with a long term goal of helping humanity settle other planets (mars being the first, perhaps only planet mentioned right now). Interplanetary is well within our realm. Interstellar, not currently.

melling3• 11 years ago

It's all good. They're bringing more money to an industry that can then fund further development. Google, for example, is mostly an ad company. They've taken all that money and built some pretty cool stuff. Among other things, we should get self-driving vehicles and futuristic robots with that money.

So, the 62 mile high space tourist plane will turn into an one orbit trip in a few years. Then to the moon in 25.

ChuckMcM2• 11 years ago

Just sort of FYI, in 1969 I was promised a tourist space station I could visit in 25 years by NASA ... (well and their lapdogs the Scholastic Press :-)

tjmc• 11 years ago

Your comment reveals stunning ignorance of Burt Rutan's contributions to aerospace.

rwallace4• 11 years ago

You're talking about different timescales. Interstellar travel is the long-term goal, but everyone understands it's not going to happen in the next decade. Thus, SpaceX is launching satellites and space station cargoes and The Spaceship Company is debugging a suborbital tourist vehicle, because these are things it is feasible to do right now.

nulltype2• 11 years ago

Why are these ships manned?

melling3• 11 years ago

You're the second guy to say this. Stop and think... Ready for it?

Because it was only months away from carrying tourists. You'll scare the tourists if you're afraid to use a human pilot.

nulltype2• 11 years ago

I bet the tourists are pretty scared now.

vilhelm_s• 11 years ago

The NTSB findings and recommendations: http://www.ntsb.gov/news/events/Documents/2015_spaceship2_BM...

znep• 11 years ago

Virgin Galactic Executive Summary of Submission on SpaceShipTwo Accident

Related Stories