When Air France Flight 447 went missing earlier this week, it left a search area the size of the continental United States. That's because the plane, like most others flying over the ocean, was outside the radar system tracking flights around the world.
Most passengers don't realize planes leave radar range about 150 miles offshore, reports CBS News correspondent Nancy Cordes.
That means there are enormous swaths of the Pacific and Atlantic Oceans where the crew is essentially on its own.
"Over an ocean there's no surveillance other than by reports from the pilots on where they are," said Robert Francis, a former National Transportation Safety Board vice chairman.
Pilots are required to radio in periodically to let controllers know when they pass navigational waypoints.
"And based on those reports the controller makes sure there is an adequate amount of time between each flight," said Bill Voss of the Flight Safety Foundation.
But if a pilot gets off course, there's no one watching to tell him.
That's what happened in 1987 when a Delta jet strayed within 30 feet of a Continental jet over the North Atlantic.
An aviation system based on satellite GPS rather than radar would enable controllers to track planes anywhere but Voss said "in lots of areas of the world there just isn't enough traffic to justify the expense of the technology when the old way still continues to work."
There is an oceanic initiative going on to create satellite tracking systems that would "essentially to cover the earth with better communications," Mary Schiavo, former inspector general of the U.S. Department of Transportation, told CBS' The Early Show. But those are only present in New York, California and Alaska.
Most of the current technology is still "pretty much like World War II, and that can be a problem, obviously, when you're looking for debris," said Schiavo.
The difficulty of ocean searches also raises questions about how flight data is collected and stored. Currently, accident investigators rely on planes' so-called "black boxes" to reveal information about pilot error or mechanical malfunction. But in some instances, , those data recorders cannot be recovered.
But it's possible, according to Schiavo, for planes to dowload that data directly to servers on the ground, making the physical black boxes unnecessary.
"That's been a big issue. The technology is now there that that can occur. You can download the information, just as this plane did."
One possible sticking point is pilots' concerns over privacy.
"Do the pilots really want airlines to be able to track what they're doing second by second? I think after an accident like this it's time to revisit it. But the technology has arrived."
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