Search crews from a half dozen countries are back in the air and on the water, hunting for missing Malaysia Airlines Flight 370.  

About ten planes and nine ships are covering a stretch of the southern Indian Ocean in a race against time.  

The airliner's black box recorder has an expected battery life of about 30 days, and experts say the batteries will fail in the next few days.  

Searchers Continue to Battle

A group of Australian aviators looking for the jetliner says morale is the least of their concerns after finding nothing for weeks.

The weather, the wind, the sea state and visibility are the main battles they're fighting in the search.

Craig Heap is captain of the Australian Air Force Group. He says they're dedicated to resolving this situation for the passengers, crew and families of the flight. 

"We are dedicated, absolutely, to resolving this ... It is very, very important to us every time we take off, every time we operate," Heap said. 

Criminal Investigation 

Nearly a month after the jetliner vanished from radar, authorities are launching a criminal investigation into its mysterious disappearance.  

The "Wall Street Journal" reports investigators have already taken more than 170 statements with more interviews to come.  

One Malaysian police chief says the investigation still may not reveal what happened to the doomed jet.

After more than three weeks, search crews are still coming up empty-handed.  

The airliner is believed to have gone down somewhere in the Indian Ocean last month, but there's still no sign of wreckage.  

Officials believe all 239 people on board were lost.

Changes in the Rules 

Malaysia Airlines is changing its rules for pilots following the disappearance of Flight 370.  

CNN reports that the airline has told its flight crews that pilots are no longer allowed to be alone in the cockpit at any time while in the air.  

If one of the pilots does leave the cockpit, a senior cabin steward must be called to sit with the remaining pilot.

That is something that has long been the law for the United States. But, the rule change comes as Malaysian authorities continue to believe that Flight 370 was deliberately taken off course on March 8 for a reason that is still unknown.