Why the Official Explanation of MH370’s Demise Doesn’t Hold Up

Interesting technical analysis of the determination of the location of Flight 370, and how it may be completely wrong. [Link]

Investigators searching for the missing Malaysian Airlines flight were ebullient when they detected what sounded like signals from the plane’s black boxes. This was a month ago, and it seemed just a matter of time before the plane was finally discovered.

But now the search of 154 square miles of ocean floor around the signals has concluded with no trace of wreckage found. Pessimism is growing as to whether those signals actually had anything to do with Flight 370. If they didn’t, the search area would return to a size of tens of thousands of square miles.

Even before the black-box search turned up empty, observers had begun to raise doubts about whether searchers were looking in the right place. Authorities have treated the conclusion that the plane crashed in the ocean west of Australia as definitive, owing to a much-vaunted mathematical analysis of satellite signals sent by the plane. But scientists and engineers outside of the investigation have been working to verify that analysis, and many say that it just doesn’t hold up.

A Global Game of Marco Polo

Malaysia Airlines flights are equipped with in-flight communications services provided by the British company Inmarsat. From early on, the lynchpin of the investigation has been signals sent by Flight 370 to one of Inmarsat’s satellites. It’s difficult to overstate the importance of this lonely little batch of “pings.” They’re the sole evidence of what happened to the plane after it slipped out of radar contact. Without them, investigators knew only that the plane had enough fuel to travel anywhere within 3,300 miles of the last radar contact—a seventh of the entire globe.

Inmarsat concluded that the flight ended in the southern Indian Ocean, and its analysis has become the canonical text of the Flight 370 search. It’s the bit of data from which all other judgments flow—from the conclusive announcement by Malaysia’s prime minister that the plane has been lost with no survivors, to the black-box search area, to the high confidence in the acoustic signals, to the dismissal by Australian authorities of a survey company’s new claim to have detected plane wreckage.

Although Inmarsat officials have described the mathematical analysis as “groundbreaking,” it’s actually based on some relatively straightforward geometry. Here’s how it works: Every so often (usually about once an hour), Inmarsat’s satellite sends a message to the plane’s communication system, asking for a simple response to show that it’s still switched on. This response doesn’t specify the plane’s location or the direction it's heading, but it does have some useful information that narrows down the possibilities.

You can think of the ping math like a game of Marco Polo played over 22,000 miles of outer space. You can’t see the plane. But you shout Marco, and the plane shouts back Polo. Based on how long the plane takes to respond, you know how far away it is. And from the pitch of its voice, you can tell whether it’s moving toward you or away from you—like the sound of a car on the highway—and about how fast.

This information is far from perfect. You know how far the plane was for each ping, but the ping could be coming from any direction. And you how fast the plane is moving toward or away from you. It could also be moving right or left, up or down, and the speeds would sound the same. The task of the Inmarsat engineers has been to take these pieces and put them together, working backwards to reconstruct possible flight paths that would fit the data.