Search crews in the Indian Ocean have reacquired the underwater signal they believe could belong to the black box of the missing Malaysian jetliner.
Australian search chief Angus Houston said a U.S. Navy towed pinger locator acquired the signal on two separate occasions Tuesday.
Houston told a news conference early Wednesday the signals will help narrow the search area, but that it still stands at 75,000 square kilometers.
The retired air chief marshal said authorities will not yet deploy a robot submarine to search the ocean floor. For now, he said, it is important that the search for signals continue.
It has now been over a month since the Boeing 777, which was carrying 239 people, disappeared en route from Kuala Lumpur to Beijing.
The batteries on the plane's black box locator beacon were expected to only last for about 30 days, meaning authorities are running out of time to locate the signals.