Rescuers were still making all-out efforts to find the bulk debris of the crashed China Northern Airline's MD-82 aircraft and its black box flight recorder Thursday, two days after it plunged into sea with 112 people aboard off northeast China's Liaoning Province.

In an interview with Xinhua, a rescue officer predicted difficulty in the search, as the wreckage might have sunk to the sea bottom along with the bodies of missing victims.

But members of the search team were motivated by the radio signal received from the black box at a place about 600 meters (656.4 yards) north of Dalian Harbor at 11:00 am Thursday.

The black box is able to automatically send signals at the frequency of 37.5 kilohertz within 30 days after the crash of the plane.

By press time, over 40 ships, equipped with state-of-the-art sonar equipment and GPS positioning systems, were still working in a three-square-kilometer area around the site of the crash.

Over 50 divers from the Chinese naval force and the Yantai Salvage Bureau were also helping to locate the data recorder, and will be sent down to pick up the device once the exact spot is determined.

The sea surface, which was covered with debris after the crash, has been cleared, thanks to the sustained search and rescue efforts since Tuesday night.

(Xinhua News Agency May 10, 2002)