Space

Human error and inadequate training blamed for SpaceShipTwo crash

Human error and inadequate tra...
The United States National Transportation Safety Board (NTSB) has blamed pilot error stemming from inadequate training for the crash of SpaceShipTwo
The United States National Transportation Safety Board (NTSB) has blamed pilot error stemming from inadequate training for the crash of SpaceShipTwo
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The new SpaceShipTwo is being built by Virgin
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The new SpaceShipTwo is being built by Virgin
Pilot Pete Siebold as he parachutes safely down to earth after the accident, with his arm up in the air to show everybody that he is alive and well
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Pilot Pete Siebold as he parachutes safely down to earth after the accident, with his arm up in the air to show everybody that he is alive and well
SpaceShipTwo team
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SpaceShipTwo team
Sir Richard Branson issuing a statement on the report
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Sir Richard Branson issuing a statement on the report
The United States National Transportation Safety Board (NTSB) has blamed pilot error stemming from inadequate training for the crash of SpaceShipTwo
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The United States National Transportation Safety Board (NTSB) has blamed pilot error stemming from inadequate training for the crash of SpaceShipTwo

The United States National Transportation Safety Board (NTSB) released the conclusions of its accident investigation into the crash of Virgin Galactic's SpaceShipTwo last year over the Mojave Desert. According to the report, the accident was due to an error by the co-pilot, who prematurely released the spacecraft's feather system, placing too much stress on the fuselage and causing it to break up.

At about 10:07 PDT on October 31, 2014, SpaceShipTwo (SS2-001) broke up in midair 13 seconds after being dropped from the WhiteKnightTwo mothership, resulting in the death of the co-pilot Michael Alsbury and severe injury to the pilot, Peter Siebold, who was thrown clear as the craft disintegrated. It was the 55th test flight and fourth powered flight of the suborbital spacecraft built by Scaled Composites, a wholly-owned subsidiary of the Northrop Grumman Corporation, for Virgin Galactic.

The spacecraft uses a hybrid rocket system to propel it on a suborbital trajectory into outer space. Key to this design is a feather system for reentry, which uses a pair of tail boom structures that pivot upright, so the spacecraft spirals down into the Earth's atmosphere like a maple seed.

Pilot Pete Siebold as he parachutes safely down to earth after the accident, with his arm up in the air to show everybody that he is alive and well
Pilot Pete Siebold as he parachutes safely down to earth after the accident, with his arm up in the air to show everybody that he is alive and well

The flight during which the accident occurred was supposed to see the spacecraft reach an altitude of 135,000 ft (41,000 m) and a speed of Mach 2. The planned program included testing of a new polyamide-based hybrid rocket motor fuel and the first supersonic deployment of the feathering system. After being dropped by WhiteKightTwo, SpaceShipTwo fired the engine and operations were normal until the feathering booms deployed prematurely. This produced high g-forces, which tore the craft into several pieces that scattered over a five-mile (8-km) area near Koehn Dry Lake, California.

The Board had access to video, on-board and telemetry data recorded during the flight, and on Tuesday released its findings and made its recommendations to the Federal Aviation Administration and the Commercial Spaceflight Federation.

According to the report (PDF), the co-pilot made an error under time pressure, vibrations and loads that he had not previously experienced. The tailboom was unlocked while SpaceShipTwo was still in the boost phase. The velocity was Mach 0.9, when the safe minimum speed for unlocking was Mach 1.4. The specifications state that, at speeds above Mach 1.4, the air pressure on the boom keeps it in place with the aid of the actuators. When the speed is lower, the boom can press up with too much force for the actuators to overcome.

SpaceShipTwo team
SpaceShipTwo team

The investigation found that the co-pilot unlocked the booms 14 seconds early when the craft was travelling at only Mach 0.92 and the low-velocity caused the boom to deploy without any action by the pilot, resulting in the destruction of the craft. This was "indisputably confirmed by telemetric, in-cockpit video and audio data." In addition, the Board found no indication of misleading display indicators and that all information in the cockpit was accurate.

The reason given for the error was that the co-pilot hadn't received sufficient training regarding how to safely unlock the boom, hadn't had enough simulation trainings, and that in flight had been confused by the time pressure and the unexpected vibration and pressure of the rocket firing.

Regarding responsibility, the Board found no mechanical shortcomings with the spacecraft. The engine performed above expectations and all systems operated as designed up until the spacecraft broke apart. The only major mechanical problem that the Board identified was the need for an automatic safety lock to prevent the booms from being unlocked below the safe speed.

Sir Richard Branson issuing a statement on the report
Sir Richard Branson issuing a statement on the report

The Board also blamed Scaled Composites for not doing enough to prevent pilot error. It said the pilots had inadequate training and experience in the operation of the craft and the danger of prematurely unlocking the booms had only been discussed once, three years before the accident.

The Board says that the FAA had noted some software and human error shortcomings, but had waived them in issuing a flight permit to them due to the experimental nature of the craft. It recommended a challenge/response routine by the crew for unlocking the booms and providing pilots with explicit warnings about improper procedures.

"Manned commercial spaceflight is a new frontier, with many unknown risks and hazards," says NTSB Chairman Christopher A. Hart. "In such an environment, safety margins around known hazards must be rigorously established and, where possible, expanded."

"Every new transformative technology requires risk, and we have seen the tragic and brave sacrifice of Mike and the recovery of injured surviving pilot Pete Siebold," said Virgin Galactic CEO Sir Richard Branson in the wake of the report. "Their tremendous efforts are not in vain and will serve to strengthen our resolve to make big dreams come true."

The video below is the statement by Sir Richard.

Source: NTSB

Richard Branson Statement 28.7.15

6 comments
VirtualGathis
I'm very glad it wasn't a complete show stopper, that the mechanical system wasn't at fault. It is disappointing that the pilots were not better trained and the challenge response was not implemented properly prior to the test flight. Mike and Pete's families should be generously compensated by scaled composites and Virgin Galactic for their oversight and the resulting injury and death. That said with the validation of the hardware's overall safety the program will continue and the dream of low cost commercial space flight with it. I hope they take the lesson to heart as this is the second death in the operation of this program. Safety must come first as the consequences of even small errors are enormous.
Kevin Ritchey
Bad stuff happens to even the best of us. Mistakes are made and sometimes sad eventualities result. I hope this doesn't dissuade the project engineers from continuing the quest for success.
habakak
'...prematurely released the spacecraft's feather system, placing too much stress on the fuselage and causing it to break up....' Can't it be said that knowing this limitation, a failsafe should have been built into the system to PREVENT it from being released prematurely (below Mach 1.4)? As always with aviation, the human is always blamed. If a human can make this mistake, shouldn't some automation be put in place to prevent this, or at least point out the consequences to the intended actions and requiring override or confirmation? Always easier to say our planes are safe, the pilot is the variable. And if a lack of training was the issue, isn't it the companies responsibility to ensure a well trained pilot/co-pilot is at the helm? Either way Virgin Galactic, this looks bad for you. You come across as being without a care about putting your passengers on a vehicle with untrained (or not sufficiently trained) pilots. Yeah, the pilot is to blame....
obscura1xero
The conclusion reached by the board, in blaming pilot error and inadequate training, is all too common in aviation. It's easy, but in this case, it's flat out wrong. Michael Alsbury is one of the pilots used in the building and testing of SpaceShipOne when Scaled Composites was going after the X-Prize. I cannot conceive of a scenario where he was "inadequately trained" by the company he had been testing and engineering for for at least 13 years on both of the projects SpaceShipOne and SpaceShipTwo. According to his short Wikipedia page, he had 1800 hours of flight time, 1600 of those with Scaled Composites alone. It's a hurtful and defamatory brush off.
Stephen N Russell
Update training, estd parameters, use Sim more, use data from shuttles as guide, Update facilities Use Remote Control for testing SS3. Change VG or we never see Space.
Calson
It was a combination of user error and inadequate design by the engineers. Good design makes it easier for the individual to do something the right way and more difficult if not impossible to do it the wrong way. My truck will not allow me to shift out of park unless I have the brake pedal depressed. This same truck will not allow me to unlock the doors while the vehicle is moving. This is not rocket science, only good design and engineering.