US captain unwilling to say whether 'black box' detected

Updated: 2014-04-08 07:10

By Karl Wilson in Perth, Australia (China Daily USA)

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US navy Captain Mark Matthews is not prepared to say whether his crew located the "black box" from Malaysia Airlines Flight MH370.

"I don't want to build up anyone's hopes," said Matthews, the navy's supervisor of salvage and diving.

"We are working within a 3-mile (4.8-km) grid and it is painstakingly slow work."

The search area in which the Australian Defence Force vessel Ocean Shield is operating is about 1,800 km west of Perth, the capital of Western Australia state.

Ocean Shield, which detected the pings late on Saturday night and on Sunday morning, is towing a pinger locator at speeds of 3.7 to 9.3 km per hour, Matthews said.

The towed underwater vehicle can detect signals from locator beacons attached to the black box.

"What it has detected so far is pulses consistent with the flight data and cockpit voice recorders," Matthews said.

The flight recorders are fitted with locator beacons that transmit pulses at 37.5 kilohertz a second for 30 days.

But the battery life of the beacon was fast running out on Monday, 31 days after the Boeing 777 with 239 passengers and crew disappeared.

All those involved in the search say the battery life can run for 40 to 45 days. But the pulses will become gradually weaker.

"I would be more confident if we could relocate those signals again," Matthews said.

"The pinger locator can track to depths of 3,000 to 6,000 meters. The problem we face is that the Bluefin-21 autonomous underwater vehicle we have can only operate to a maximum depth of 4,500 meters.

"We think the wreck site is at that depth but really don't know. Water around there varies from 5,000 to 6,000 meters. It is very, very deep.

"First, we need to find the debris field and start to process it. The black box will lead us to that field. Once the field has been established, we will send the Bluefin down with a camera.

"That vehicle can only see a few meters. Sonar can extend its range to around 100 meters. So what Ocean Shield can accomplish in one day would take a week using the underwater vehicle.

"Am I confident we have found the site of the aircraft? I can't say. I will need to wait until I can get an assessment from my crew."

karlwilson@chinadailyapac.com

(China Daily USA 04/08/2014 page5)

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