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Poor Pilot Training Blamed For Virgin Galactic Crash
astroengine writes: SpaceShipTwo co-pilot Michael Alsbury was not properly trained to realize the consequences of unlocking the vehicle's hinged tail section too soon, a mistake that led to his death and the destruction of the ship during a test flight in California last year. Responsibility for the accident falls to SpaceShipTwo manufacturer Scaled Composites, a Mojave, Calif., company owned by Northrop Grumman Corp, the National Transportation Safety Board (NTSB) determined at a webcast hearing on Tuesday (PDF). Poor oversight by the Federal Aviation Administration, which oversees commercial spaceflights in the United States, was also a factor in the accident, the NTSB said.
If there was a criteria for safe unlocking of the hinged tail section then why wasn't it interlocked until the criteria was satisfied?
A bigger error here is reliance on operator training. It's the least reliable form of ensuring a certain outcome.
From the report:
The unlocking of the feather during the transonic region resulted in uncommanded feather operation because the external aerodynamic loads on the feather flap
assembly were greater than the capability of the feather actuators to hold the assembly in the unfeathered position with the locks disengaged.
So maybe the copilot thought that he was preparing for the future feathering operation by unlocking it, and he did not think he was initiating the feathering. Usually an "unlock" switch is only a permissive, and it does not initiate the actual operation.
That's pretty standard for all aviation training. Flying is easy, much easier than driving in a lot of ways. Not killing yourself is a lot harder. That's why pilots have reams and reams of checklists covering pretty much every conceivable problem that can happen. Similarly when training in a simulator, the operators can pretty much throw the book at you to see how you react to losing all your instruments and a wing while flying through a thunderstorm.
NASA's generic rulebook is over 2000 pages long and is well worth a flick through if you're a space geek http://www.jsc.nasa.gov/news/c...
You're an experienced test pilot of a rocket powered ship and you have to be specifically trained to anticipate the effects of slamming on the brakes while traveling at supersonic speed?
As touched on in a comment above, he didn't deploy them, he unlocked them. As I understand it, he unlocked them too early, so the deployment mechanism was unable to prevent them from deploying under the stress of supersonic flight at relatively low altitude.
You want to unlock them early, because, if you can't unlock them, you can still cut the engine and glide back. You don't want to unlock them too early, because this happens.
No laws were broken. There is no way to levy a fine. The NTSB is not in the business of fining individuals or organizations for violating rules or laws. That's the job of the FAA and other various agencies that oversee road vehicles, trains, and boats.
The NTSB does their best to identify the probable cause(s) of the incident, what factors led up to that incident, and, most importantly, what measures to take to prevent any future incidents. It's up to agencies, like the FAA in this case, to implement suggestions from the NTSB.
In this case, most of the blame appears to fall on the FAA.
It appears that deploying the feather was a multi-step operation. The flap covering the feather is unlocked, then the flap is opened, then the feather is deployed. The pilot probably knew that the feather could not be deployed at the speed they were going, but did not know/understand that the flap could not stay closed if unlocked at the speed they were going. Thus, the pilot unlocked the flap, and from there, whatever other latch that made step 2 work broke, the flap opened and the feather deployed on its own.
Maybe the button will be renamed "Remove Restraints Holding Feather Flap Closed During Transonic Region".
I have read the NTSB Executive Summary. As far as I have seen, the full report has not yet been made available.
The claim made by the report is the accident was the result of human error because one of the pilots unlocked the feather prematurely and that the actuators that control movement of the feather were overcome by aerodynamic forces (while going through trans-sonic speeds) and the feather moved. Deploying the feather is a two-step process, unlocking, which one pilot can do, and commanding it to move, which require both pilots to take action.
What I didn't see in the Executive Summary was whether Scaled Composites expected the actuators to be able to control movement of the feather while the vehicle was going trans-sonic.
Just after the accident, there were statements attributed to Scaled that the actuators should have been able to hold the feather in position after it was unlocked. If the people working on and with the vehicle thought this, how could it be human error for the feather to be unlocked when it was?
If it turns out that those earlier statements were incorrect and Scaled knew that it was a bad idea to, say, unlock while going through trans-sonic, then the Executive Summary should have indicated that. I just find it odd that it doesn't say anything about what Scaled had communicated to its pilots about the capabilities of the actuators for the feather once it was unlocked.