Official: U.S. 'pinger locators' joining search

WASHINGTON (CNN) - The U.S. Navy on Monday was sending two high-tech acoustic devices to help search for emergency beacons from downed Air France Flight 447, which crashed into the Atlantic Ocean, a U.S. defense official told CNN.

Authorities hope the "towed pinger locators" will help recover the plane's flight data recorder and cockpit voice recorder, which could shed light on what caused the plane to crash last Monday.

"Pingers" - underwater locator beacons attached to flight data and cockpit voice recorders - can transmit signals from as deep as 14,000 feet, about the maximum depth of the water in the area where the plane apparently went down. The flight recording devices are designed to emit a regular ping for 30 days after a crash.

Towed pinger locators, which can help search for emergency beacons on downed aircraft to a maximum depth of 20,000 feet, will be placed aboard two French tugs that are part of the search efforts, the official said.

The pinger locators - which are owned by the Navy but operated by contractors - were being sent to Natal, Brazil, from Washington via commercial air on Monday, the official said. A joint military-contractor team also was heading to Brazil to aid in the search, the official said.