Missing Malaysia Airlines Flight MH370: Huge international aerial search operation ends as authorities expand underwater search effort

Despite a massive international search effort not a single piece of debris from the flight has been found

The huge multinational aerial search operation attempting to locate missing Malaysia Airlines flight MH370 has been called off as authorities expanded the underwater search to include a vast swathe of ocean floor that may take at least eight months to thoroughly examine.

Despite a massive international effort not a single piece of debris from the flight has so far been found.

The flight, which disappeared during a routine journey from Kuala Lumpur to Beijing on Saturday, March 8th, had 239 people on board.

The Australian Prime Minister Tony Abbott announced the end of the aerial search yesterday.

"It is highly unlikely at this stage that we will find any aircraft debris on the ocean surface. By this stage, 52 days into the search, most material would have become waterlogged and sunk," Mr Abbott said.

"Therefore, we are moving from the current phase to a phase which is focused on searching the ocean floor over a much larger area," he said.

The US Navy's Bluefin 21 robotic submarine has spent weeks scouring the initial search area for the plane in the remote Indian Ocean far off Australia's west coast, but has found no trace of the missing aircraft.

Officials are now looking to bring in new equipment that can search a larger patch of seabed for the plane, Abbott said. After seven weeks of searching the air effort is now over, some ships, however, will stay on the Indian Ocean in order to gather any debris that may surface.

The air search involved around 600 military personnel from at least seven countries. They solemnly posed for a commemorative photograph today to mark the end of the air effort.

Most of the air crews will leave the Royal Australian Air Force Base Pearce, near Perth, over the next few days.

Radar and satellite data show the jet veered far off course for unknown reasons during a flight from Kuala Lumpur, Malaysia, to Beijing. Analyses indicate it would have run out of fuel in the remote section of ocean where the search has been focused.

The unmanned sub has been creating a three-dimensional sonar map of the ocean floor for more than two weeks near where signals consistent with airplane black boxes were heard on April 8. The sub has searched a nearly 400-square kilometer (150-square mile) area.

Crews will now begin searching the plane's entire probable impact zone, an area 700 kilometers (430 miles) long and 80 kilometers (50 miles) wide, Abbott said.

That will be a monumental task — and one that will take time, warned Angus Houston, head of the search effort.

"If everything goes perfectly, I would say we'll be doing well if we do it in eight months," Houston said, adding that weather and technical issues could prolong the search well beyond that estimate.

Australian officials will be contacting private companies to bring in additional sonar mapping equipment that can be towed behind boats to search the expanded area at an estimated cost of $60 million, Abbott said. It could take officials several weeks to organize contracts for the new equipment and the Bluefin will continue to scour the seabed in the meantime, Abbott said.

So far, each country involved in the search has been bearing its own costs. But Abbott said Australia would now seek contributions from other countries to help pay for the new equipment.

Additional reporting by AP