Missing MH370: More signals detected

Two more underwater signals that may be emanating from the missing Malaysian jet's black boxes have been detected with the head of the search team today expressing optimism about finding the final resting place of the aircraft in the "not too distant future".

Australian ship Ocean Shield had first picked up the underwater pulses on Saturday but for the next three days, nothing was recorded.

The ship once again reacquired the signals yesterday, taking the total number of "pings" heard possibly from the black box of the ill-fated Malaysia Airlines Flight MH370 to four.

All of the pings or signals have been recorded are within approximately 27 kilometres of one another.

"Ocean Shield has been able to reacquire the signals on two more occasions, late yesterday afternoon and later last night," Angus Houston, head of the Joint Agency Coordination Centre which is leading the search, said today.

Houston said the detection yesterday afternoon was held for approximately five minutes and 32 seconds and the detection late last night was held for approximately 7 minutes.

The new information has narrowed the search area to 75,000 square kilometres.

In another major development in the search for the plane, Australian authorities analyzed the signals picked up on Saturday and determined that they were not natural occurrences, but likely came from specific electronic equipment. Some marine life make similar sounds.

"They believe the signals to be consistent with the specification and description of a flight data recorder," Houston said.

"I'm now optimistic. We'll find the aircraft or what's left of the aircraft in the not too distant future," he said.

"I believe we are searching in the right area but we need to visually identify wreckage before we can confirm with certainty that this is the final resting place of MH370," Houston said.

He, however, said they were not yet at the point of deploying the underwater autonomous water vehicle.

"The better Ocean Shield can define the area, the easier it will be for the autonomous underwater vehicle to subsequently search for aircraft wreckage," he said.

Finding the black box is crucial for knowing what happened on March 8 before the Beijing-bound Malaysia Airlines Boeing 777 flight MH370 with 239 people, including five Indians, disappeared under mysterious circumstances.

The batteries powering the black box are certified to be working for 30 days. Stored in a plane's tail, they are designed to begin sending off distinct, high-pitched signals as soon as they come in contact with water.