S2Ep11 How The Plane Broke

Pieces of a plane wreck tell a story. What do MH370's say?

Black box data is the ne plus ultra of aircraft accident investigation. But it is not the only kind of physical evidence. Pieces of debris—in particular, their dents and fractures — can tell a vivid story in themselves.

When a plane crashes, it’s common for all different parts to exhibit different kinds of failure. Imagine a plane whose wingtip hits a tree. The impact would crush the leading edge of the wingtip—compression failure—and then wrench the wing backwards from the body of the plane, causing a tension failure at the forward wing root and compression failure at the aft end.

By collecting many pieces of debris after a crash, investigators can place the mechanical failures in a chronological order to tell a story that makes sense, much as you might arrange magnetic words on a refrigerator.

This is how the mystery of TWA 800 was solved. On July 17, 1996, about 8.30 in the evening, a Boeing 747 carrying 230 people exploded off the coast of Long Island 12 minutes after takeoff from JFK. The horrific accident, which at the time was the third deadliest in US history, sparked a four-year investigation. Eventually thousands of pieces of debris, making up some 95 percent of the aircraft, were recovered. By examining each closely, investigators were able to piece together the sequence of events. An electrical fault had caused a fuel tank to explode. The expanding gases blew the fuselage apart like a balloon, result in widespread tension failures as the structure was pulled apart. The remaining pieces of the plane fell into the sea, where they largely experienced compression forces that resulted in the pieces being crushed.

In today’s episode we’re going to try to apply the same approach the pieces of MH370 debris that were recovered.

In April of 2017 the Malaysian government published a series of documents entitled “Debris Examination Report” describing 20 pieces of debris that were deemed either confirmed, highly likely or likely to have come from the plane. For 12 of them, investigators were able to discern the nature of the mechanical failure. The overwhelming majority were tension failures, meaning that they showed evidence of having been pulled apart.

This might seem a little surprising, given that authorities believe the plane crashed into the sea at very high speed. In a 2017 interview, a professor of accident investigation at Embry Riddle Aeronautical University, Bill Waldock, told me that in such circumstances you’d expect to see breakage under compression.

However, I also spoke to an expert who took part in the MH370 investigation, who wasn’t authorized to speak publicly about official findings. He told me that, while Australian officials had been unable to find a comprehensible narrative in the pieces they collected from MH370, that wasn’t entirely surprising to him. To really tell a coherent, consistent story from pieces of debris, you need a lot of them, as was the case with TWA 800. Not only were only a dozen pieces of MH370 collected that contained clues about how they’d broken, but most of these pieces did not normally experience aerodynamic forces, so were less informative in putting together a sequence of events.

In short, he said, the debris didn’t tell us any kind of simple, incontrovertible story about how the plane hit the water. That’s in contrast to some self-proclaimed experts who say that, based on their examination of photographs of MH370 debris, they can tell exactly what happened to the plane.

Once again, when contemplating evidence that might tell us what happened to MH370, we’re instead left scratching our heads.