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Airlines urge more security, passenger checks
Under normal circumstances, ground-based air traffic controllers use radar and other equipment to track all aircraft in their area of reach and direct planes so they are at different altitudes and distances. This enforced separation — vertical and horizontal — prevents collisions. But the planes searching for Flight 370 are operating over a remote patch of ocean that is hundreds of kilometers (miles) from any air traffic controller.
Houston, a former Australian defense chief, called the search effort the most challenging one he has ever seen. The starting point for any search is the last known position of the vehicle or aircraft, he said.
"In this particular case, the last known position was a long, long way from where the aircraft appears to have gone," he said. "It's very complex, it's very demanding."
"What we really need now is to find debris, wreckage from the aircraft," he said. "This could drag on for a long time."
Items recovered so far were discovered to be flotsam unrelated to the Malaysian plane. Several orange-colored objects spotted by plane Sunday turned out to be fishing equipment.
McGuirk reported from Canberra. Associated Press writers Eileen Ng in Kuala Lumpur, Kristen Gelineau in Sydney, and Jocelyn Gecker in Bangkok contributed to this report.