PERTH, Australia - After a navy ship heard more signals from deep in the Indian Ocean, the head of the search for the missing Malaysian jetliner said Wednesday that he thinks the hunt is closing in on the "final resting place" of Flight 370.
The Australian vessel Ocean Shield picked up two signals Tuesday, and an analysis of two other sounds detected Saturday showed they were consistent with a plane's flight recorders, or "black boxes," said Angus Houston, the Australian official coordinating the search for the Malaysian Airlines jet.
"I'm now optimistic that we will find the aircraft, or what is left of the aircraft, in the not-too-distant future," Houston said. "But we haven't found it yet because this is a very challenging business."
Finding the flight data and cockpit voice recorders soon is important because their locator beacons have a battery life of about a month, and Tuesday marked one month since Flight 370 vanished March 8 en route from Kuala Lumpur, Malaysia, to Beijing with 239 people aboard.
If the batteries fail before the recorders are located, finding them in such deep water - about 15,000 feet - would be difficult, if not impossible.
"I believe we are searching in the right area, but we need to visually identify aircraft wreckage before we can confirm with certainty that this is the final resting place of MH370," Houston said. "For the sake of the 239 families, this is absolutely imperative."
The search zone for today has been narrowed to its smallest area to date - 22,364 square miles of ocean that extend from 1,417 miles northwest of Perth, Houston's coordination center said.
The center's statement did not say whether any further sounds had been heard since Tuesday.