OK, everybody.
The NTSB just completed its final media briefing on the SpaceShipTwo investigation. And this story got stranger.
During the Q&A, NTSB Acting Chairman Christopher Hart appeared to back off his claim yesterday that it was co-pilot Mike Alsbury, who died in the crash, unlocked the feather mechanism at Mach 1.0 instead of Mach 1.4. The unlocking of the mechanism in the heavier air during powered acceleration caused the twin tail booms to move in conditions they were not designed to perform in. The tail booms ripped off the ship in two seconds, causing SpaceShipTwo to disintegrate.
Hart indicated that he was mistaken in his statement on Sunday night, and that officials were not sure who the pilot in the right-hand seat was who unlocked the feather mechanism. He ended the briefing without clarifying how such a mistake could have been made. Pilots are always in the left-hand seats while co-pilots sit in the right-hand one.
After the briefing, one of Hart’s deputies clarified his statement. The deputy said the co-pilot was in the right-hand seat, the co-pilot unlocked the feather, and the co-pilot did not survive the accident. That would be Alsbury, as Hart had indicated on Sunday.
So, what’s going on here? That’s where things got really interesting.
The Washington Post has a story on its website tonight that likely explains what Hart was trying to say. Under flight rules, the decision to unlock the feather mechanism is not the co-pilot’s alone but involves communication with the pilot — in this case, Peter Siebold, who survived the crash. I’ve added emphasis to the relevant text.
Employees at Scaled Composites, the firm that designed the space plane, on Friday were able to watch video camera feeds from inside the cockpit and outside the spaceship during its flight.
“There are dozens of reasons why mistakes like this one could be made,” said another Scaled test pilot.
That pilot went on to explain that there was a rule that anyone flying the spaceship could not re-configure the vehicle without the verbal acknowledgment of both pilot and co-pilot. It is unclear whether that protocol was followed. Normally, the co-pilot would announce when Mach 1.4 had been reached — the proper speed to unlock the feather. The pilot would acknowledge and command the co-pilot to unlock the feather. Once the feather was unlocked, the co-pilot would announce the maneuver had been completed.
A number of sources, who spoke on the condition of anonymity because the company has forbidden interviews with the media, described seeing Alsbury unlock the feather and then appear to realize there was an error, moving quickly as if he was trying to shut off the motor, but it was too late.
These sources said that within the company, there is a growing recognition that Alsbury, the co-pilot, unlocked the feather early, although it is not clear why. Colleagues say Alsbury was one of the sharpest test pilots on the team, with more than 1,600 hours of flight experience in more than nine different aircraft.
The first 15 seconds of the burn are incredibly chaotic for the pilot and co-pilot. Lighting the rocket motor is akin to opening the gate at a rodeo — the bull starts bucking and the pilot is just along for the ride, tossed back into the seat with three times the force of gravity and pushed down with even more force.
During this period, the pilot and co-pilot go through their flight-test cards, performing a number of “housekeeping” duties meant to prepare the ship for the remainder of the flight.
I asked Hart whether investigators had been able to review cockpit data to determine what the pilots were seeing on their instruments in terms of air speed. He said that they had not yet reviewed that data.
Hart said that the investigation team would be forming a new human factors group that will investigate human-machine interactions and their possible impact on the accident.
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