Guest post by George Bibel
Air France Flight 447, which was lost in the Atlantic Ocean on June 1, 2009, gives us some insight into why it has been so difficult to recover debris from Malaysia Airlines Flight 370.
In 2009, investigators were unable to find much debris from Flight 447, and many of the pieces that they did find were small. Only 3% (about 1,000 pieces—mostly chunks of insulation and honeycomb construction) of the plane was discovered floating on the surface of the water. The twenty-five foot long composite vertical stabilizer was the biggest floater. (A Boeing 777 like the Malaysian Airlines plane also has composite tail sections.) The biggest piece of fuselage, found on the ocean floor, was only twenty-three feet long.
Debris was also hard in part to find because it spread so quickly. Seventeen days after the crash, the debris and bodies from Flight 447 had drifted 100 miles. On day twenty-five, the debris scatter spanned 200 miles. In addition, depending on water temperature, a body will float for perhaps two to three weeks. Only fifty bodies were recovered back in 2009. At this point, Flight 370 has been missing for more than a month.
Flight 447 completely fragmented on impact. (A belly flop with a vertical sink rate of just 30 mph will severely fragment the plane.) Pieces that float can be torn out as the plane breaks up entering the water.
On the other extreme, a plane going down in the water under pilot control may still break up, which is not good; but the emergency slides double as rafts with radio beacons. In 1996, Ethiopian Airlines Flight 961 was hijacked, ran out of fuel, and went down in the Indian Ocean. The hijackers actually fought the pilot for control of the airplane during the water landing. One hundred and twenty-five out of one hundred and seventy-five passengers died. Most likely more would have lived if the pilot had had full control. If Flight 370 had crashed in this manner, we most likely would have found survivors weeks ago or picked up a signal from the raft beacons.
Finding the black boxes may not be the end of the mysterious story of Flight 370. According to one experienced Airbus/Boeing pilot (the coauthor of my next book), black boxes can be shut off with circuit breakers in most aircraft. In many situations, pilots are required to remove power from the cockpit voice recorder by using the circuit breaker after an incident or accident to preserve the data. And most cockpit voice recorders only record the last two hours, raising the possibility that evidence of a struggle in the cockpit earlier in the flight may have been overwritten.
George Bibel, a former NASA summer faculty fellow, is the author of Beyond the Black Box: The Forensics of Airplane Crashes, published by Johns Hopkins. He is a professor of mechanical engineering at the School of Engineering and Mines, University of North Dakota. He recently completed the Air Line Pilots Association advanced accident investigation course.
