A picture taken of a computer monitor shows a piece of unknown debris floating just under the water that was spotted from a Royal New Zealand Air Force (RNZAF) P3 Orion maritime search aircraft while flying over the southern Indian Ocean looking for missing Malaysian Airlines flight MH370 March 31, 2014. Australian Prime Minister Tony Abbott said on Monday the hunt for Malaysia Airlines Flight MH370 had no time limit, despite the failure of an international operation to find any sign of the plane in three weeks of fruitless searching. A total of 20 aircraft and ships were again scouring a massive area in the Indian Ocean some 2,000 km (1,200 miles) west of Perth, where investigators believe the Boeing 777 carrying 239 people came down. REUTERS/Rob Griffith/Pool (AUSTRALIA - Tags: MILITARY TRANSPORT DISASTER)