As the intensive hunt for Malaysia Airlines Flight 370 entered its second month on Tuesday, the only certainty was that it would become the most expensive search and recovery effort in aviation history, with an international fleet of ships and planes scouring the Indian Ocean at a cost of millions of dollars a day.

For the most part, the dozens of countries that have contributed personnel, equipment and expertise to the search have borne the costs while declining to disclose them, with officials offering a united front in saying it would be callous to talk about money while a commercial airliner and the 239 people aboard remained unaccounted for.

On Wednesday, officials reported that an underwater signal had been detected on two occasions the day before, reviving hopes that they still might locate the Boeing 777-200's data and voice recorders. Still, many of the governments involved may soon face a tough decision about whether to keep bearing the extraordinary costs of the search, analysts said.

"Each country will have to ask itself: What are the prospects of further investigation and the cost-benefit of it?" said Ramon Navaratnam, chairman of the Center for Public Policy Studies at the Asian Strategy and Leadership Institute in Kuala Lumpur. "If there's no prospect, there's no prospect: We have to be very realistic. But it's a very difficult to decision to make. It's like someone on a medical support system and you have to determine whether to pull the wires or not."

Until now, the costliest search and recovery effort ever undertaken followed the crash of Air France Flight 447 hundreds of miles off the coast of Brazil in 2009, reaching about 115 million euros, roughly $160 million at the time, over the course of two years, according to estimates by experts who participated in that effort

Source: KUNA