Tim Blagg

Blagg: Time may be running out

Somewhere on the bottom of the Indian Ocean, some 1,000 miles west of Australia, three miles down, there may be an answer to the mystery that’s been baffling the world for the last month.

Is the wreckage of Malaysian Airlines Flight 370 lying there, its “black box” flight recorders faithfully emitting a stream of signals?

We don’t know.

All we know for certain is that the flight took off for Beijing and never arrived, carrying 239 souls to their unknown destination. If we could recover the data recorders — one carrying information about the aircraft’s speed, altitude and engine settings, the other voice recordings from the cockpit — then we might be able to figure out what happened.

Was it a terrorist attack of some kind? Did a member of the crew decide to carry out an elaborate form of suicide? Were they overcome by some airborne illness? Was there a massive technical catastrophe?

Or was it some other scenario that we simply don’t have the imagination to come up with?

Without finding the wreckage and/or the recorders, we may never know.

One major problem in doing that is the remote location. It’s almost exactly on the opposite side of the Earth from Franklin County, Mass. There are vast expanses of ocean there, on the southern limit of the Indian Ocean, bordering the great Southern Ocean, which runs clear around the world on the border of Antarctica.

It’s nearly 6,000 miles — three times the distance between New York and Los Angeles — from Perth, Australia, to the nearest land to the west: Madagascar. And there’s nothing between but rolling ocean and heaving waves. Giant storms build up enormous waves in the Southern Ocean as the winds blow ceaselessly around the globe.

Search crews either have to fly from Perth, taking two to three hours just to reach the possible wreck site or use ships that have to try to keep tabs on their location despite wind, currents and a lack of navigational aids.

Some 15,000 feet below them, the ocean floor is cold, black and forbidding. If the aircraft wreckage is there, it’s subject to enormous pressure — some three tons per square inch.

The “black box” (actually bright orange) on an aircraft is located in the tail, where it’s most likely to survive an accident. When it’s exposed to water, it begins to “ping” an acoustic signal that can be picked up by search equipment.

Since modern naval aircraft are designed to detect submarines by dropping sonar buoys, they are ideally suited to find pingers. The Royal Australian Air Force flies Lockheed P-3 Orions — a military version of the old Lockheed Electra airliner — that are very similar to the ones used by the U.S. Navy.

In recent days, aircraft and ships have detected what might be the characteristic pings of a flight data recorder in the search area.

But the pressures and temperatures deep in the ocean can do strange things to underwater sound. I spent quite a bit of time in my younger days working on underwater sound research. Our lab in Bermuda, on contract to the Navy, experimented with what was called the “sound channel axis,” a deep water phenomenon that can allow sounds to travel enormous distances. But rapid changes in ocean temperature can also cause “thermoclines” which form barriers to sound.

So the pings could be traveling very far, or be inaudible when quite close.

And, sound traveling at depth can be “attenuated,” which means its frequency can change over distance, making it hard to be sure the pings are in fact from a crashed aircraft.

Searchers are using a towed sonar receiver, and plan to switch to an underwater “smart” torpedo called Blue Fin, which can dive by itself to an area and search it using sonar. It has a limited range, but if the pings can be accurately localized, it could be used to locate wreckage.

Then other submersibles, using remote manipulators, could retrieve the data recorders.

That’s a lot of “ifs.”

On the other hand, the recorders from Air France Flight 447 WERE recovered, even though they lay 12,500 feet down in the Atlantic between Africa and South America. In that case, searchers found floating debris, including bodies, which helped pinpoint the crash site.

So the present search could theoretically be successful. The batteries on the recorders, however, are running down, and the clock is ticking on finding a solution to this baffling mystery.

Blagg has been Editor of The Recorder since 1986. He lives in Greenfield and is a military historian with an interest in local history. He can be reached at: tblagg@recorder.com or 413-772-0261, ext. 250.

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