The search for the Malaysia Airlines Boeing 777 that disappeared somewhere between Kuala Lumpur and Beijing on Saturday is the latest in a string of accidents in which airliners have disappeared into the sea.
You'd think something as big as a passenger jet would be easy to find, even in pieces, but the ocean is immense, much of the plane sinks and it can be surprisingly difficult to locate a wreck, especially when no one really knows where it went down.
Sometimes planes are never found. In January 1979, a Varig Brazilian Airlines Boeing 707 took off from Narita International Airport near Tokyo, bound for Rio de Janeiro via Los Angeles. A half hour into the flight, roughly 320 kilometres from Japan over the Pacific Ocean, the big jet disappeared with its crew of six and a cargo of paintings from an exhibit in Japan. No trace of the plane, the crew or the paintings has been found.
Technology has come a long way since then, though. Thirty years later, in June 2009, an Air France Airbus A330 with 228 aboard took off from Rio on its way to Paris, flew into stormy weather over the Atlantic and disappeared. Floating wreckage was spotted from the air within two days, but the ocean where the plane disappeared is 3,960 metres deep, and it took 23 months and robot submarines to locate the plane's black boxes.
Finding the cause of the crash is even harder, because there are so many possibilities and because investigators often have so little to work with. There's rampant speculation about what happened to Malaysia Airlines Flight MH370, and any theory could be right: A hijacking gone bad? A terrorist bomb like the one that blew a hole in the side of a Pan Am airliner over Lockerbie, Scotland, in 1988? Accidental decompression at 35,000 feet that sucked the oxygen out of the plane and starved the pilots of oxygen the way it did to everyone aboard golfer Payne Stewart's private jet in 1999? Sudden structural failure, as in the China Airlines 747 that disintegrated over the Taiwan Strait in 2002 when a shoddy 20-year-old repair gave way?
In many cases, given enough time and evidence, investigators do remarkable work to piece together what really happened.
Sometimes it's sinister, such as when one of the pilots of Egypt Air Flight 990 in 1999 waited for the other pilot to leave the cockpit and said, "I rely on God," pulled the throttles back to idle and nosed the plane into the Atlantic off Nantucket, killing all 217 aboard.
Sometimes it's simply a tiny, unseen malfunction, such as the wire that arced and touched off an explosion in the centre fuel tank of TWA Flight 800 off Long Island in July 1996, sending it into the Atlantic.
And sometimes it's simply pilot error. When investigators finally found the black boxes from the 2009 Air France crash in the Atlantic, they concluded the plane's pitot tubes -- the external instruments that measure airspeed -- had iced up, disconnected the autopilot and sent faulty speed readings to the pilots' instruments. In the middle of the night, in the middle of a storm, the pilots were confused about what the plane was actually doing and stalled it -- a mistake so basic but so dangerous that student pilots are taught how to avoid it during their first hours in the air. The out-of-control plane plummeted for four minutes and more than 11 kilometres until it hit the water.
Like the Air France crash, the latest airliner disappearance is a powerful argument for upgrading black-box technology to allow planes to live-stream vital information when they get into trouble -- a suggestion airlines have resisted because of the cost. Crashes like these are rare, but when they happen, finding the wreckage consumes enormous resources, and teasing out the causes can take years. Live-streamed data from black boxes could begin to answer both those questions almost instantly.
Chances are good the Malaysia Airlines 777 will be found, and chances are almost as good that investigators will figure out what happened. Until then, it's best not to jump to conclusions. At this point, all the guesses are just guesses.
The presence of two men with forged passports on disappeared airliner is proof of something far more common than terrorists, Joshua Keating writes at wfp.to/comment