At dawn yesterday the first of an international air fleet lifted off yet again from the Australian Air Force's big Pearce base north of Perth and headed towards one of the most remote and inhospitable regions on Earth.

Behind it others were waiting their turn to fly the 2500km to the search area, continuing the hunt for large debris that could be wreckage from the missing Malaysian Boeing 777 airliner.

The early morning at least held promise of good weather for the searchers. The big high over the Indian Ocean that has pushed temperatures in Perth into the 30s has also widened the horizon for a hunt that depends heavily on human eyeballs. Visibility was reportedly about 10km.

There has been little other joy since satellite pictures showing possible remains of flight MH370, lost on March 8 with 239 people aboard including New Zealanders Paul Weeks and Ximin Wang.


On Saturday the RNZAF P3K Orion based at Pearce investigated reports from a civilian search plane that small objects were floating in the area, but found only clumps of seaweed. The crew dumped a datum marker buoy to track the material, and a merchant ship was sent to hunt it down.

Chinese satellite images released on Saturday night showing an object 22m long and 13m wide - about the size of a 777 wing - raised hopes.

But it was filmed only 120km from the position of the US imagery taken on March 16, and the Australian Maritime Safety Authority said the area had been covered on Saturday without any sightings.

The search has overridden regional tensions and employed both secret military and commercial technology that is leading to rival powers working together.

At Pearce air base RAAF Group Captain Craig Heap is co-ordinating a growing multinational air fleet: four Australian and New Zealand Orions, a US Navy P8 Poseidon, two long-range commercial jets and two big Chinese R76 transports. They will be joined by two Japanese Orions.

Regional tensions have also been set aside at sea. In January exercises by Chinese warships near Australia sparked deep concern. But after discussions between Australian Prime Minister Tony Abbott and Chinese President Xi Jinping, a new flotilla is on the way.

This includes the 20,000 tonne amphibious assault ship Kunlunshan, the air defence destroyer Haikou, the big supply ship Qiandaohu and the icebreaker Snow Dragon. Four more warships will also join the search.

The Australian fleet oiler HMAS Success and two merchant vessels, one the huge 27,300 tonne Norwegian cargo ship Hoegh St Petersburg, were yesterday working in the 36,000sq km search area. Other ships are on their way. Even with these resources the task is immense. The vast search area lies 3.5km above an undersea ridge called the Naturalist Plateau. The surrounding ocean plunges to 5km, and on the surface is pushed by currents running at about 1m a second.

The technology employed is awesome. The images of the possible wreckage released last Thursday were taken by a Worldview-2 satellite operated by US company DigitalGlobe, which scanned recorded imagery after the United Nations asked for space agencies' help in the search.

The technology aboard the aircraft and warships is equally sophisticated, employing state-of-the-art optics, radars able to screen out spray, rain and other clutter, and infra-red cameras. But much will still depend on human eyes.