The Final Minutes of Air France 447

Today, France's civil aviation authority released the first details from the flight data recorders of Air France 447, which wrecked in the Atlantic Ocean two years ago after taking off from Rio de Janeiro, killing everyone on board. The new information begins to fill in the picture of what happened up there, but leaves many open questions about both the actions of the crew and the subsequent behavior of the aircraft.

Most Popular

For two years, the aviation world has been waiting to find out what the black boxes from Air France 447 would reveal about the doomed airliner's fate. Today, French aviation authorities offered a first glimpse, releasing a four-page document that, while light on details, offered a summary timeline of events in the last few minutes before the plane crashed into the South Atlantic.

The data recorders tell a chaotic tale: At 2 am Greenwich Mean Time on June 1, 2009, as the plane is about to enter an area of heavy thunderstorms, one of the two co-pilots makes an announcement over the PA system that the flight will soon be experiencing increased turbulence. Other flights crossing this stretch of ocean around the same time have gone out of their way to avoid the storms; evidently the co-pilots believe they can pick their way through the worst of it with their weather radar. At 2:08, one says to the other, "You can maybe go a little to the left." The plane starts a gentle left turn.

Advertisement - Continue Reading Below

But apparently the weather is worse than they had anticipated. Just two minutes later, the autopilot disengages itself, forcing one of the co-pilots to take manual control of the plane. He pulls back on the controls, sending it into a climbing left turn. Though his indicators are showing a dramatic loss of speed, he continues to pull back, and the plane experiences an aerodynamic stall. With a catastrophic loss of lift, the plane plummets at 10,000 feet per minute.

Most Popular

At 2:14 am, Air France 447 hits the water. When it does, it is traveling at 107 knots with its nose still high, at an angle of 16 degrees above the horizon.

What does this report tell us that we didn't know already? First, it largely confirms the rumors that have been swirling in the press over the course of the last week. The captain was away from the cockpit when the crisis began to unfold, and the plane pitched up during the crisis, contributing to an aerodynamic stall. The speed and angle of the plane as it crashed explains the condition of some of the recovered crash debris, which showed compression from below.

One surprising fact that emerged today is that the co-pilots at the controls spent most of the final moments trying to raise the nose of the Airbus 330. As even the most inexperienced pilot knows, pointing the plane upward is the worst thing to do in the event of a stall. Two possible explanations come to mind. The first is that he panicked. The second is that he believed that the plane had not stalled, but rather that it was caught in an intense downdraft; these are known to reach speeds of up to 100 mph inside thunderstorms.

Another surprise is that after the aircraft stalled, it remained in a nose-high position. Normally, when an aircraft stalls, the wing loses lift and the nose pitches downward quickly, which allows the plane to regain airspeed and recover from the stall. But that didn't happen in this case. Aeronautical engineer Martin Hollman tells PM, "I've studied a lot of aircraft accidents, and sometimes you just have to scratch your head."

Most likely, what happened is that the aircraft was traveling so slowly at the top of its brief climb that it entered what pilots call a "mush," a gentle stall in which the wing maintains some lift and the horizontal stabilizer maintains enough aerodynamic force to keep the nose pitched up. If so, the only thing that kept the airplane from reverting to a nose-down attitude would have been the pilots holding the stick back.

Later this summer, French authorities will release more detailed information from the flight data recorders, which hopefully will at last put the riddles of AF447 to rest. "So far, we've only been getting sporadic pieces of information," airline pilot and aviation consultant Christopher Nutter says. "We don't have anything detailed enough yet to form a logical inference about what happened. We're going to have to wait."



Are the Pilots to Blame? Not So Fast >>>

More from Popular Mechanics: