Missing plane search drone revealed

PLEASE NOTE: CONTAINS STILL IMAGES OF MIXED SIZES

This is the Bluefin-21 Autonomous Underwater Vehicle search teams are using in the hunt for missing Malaysia Airlines flight MH370 and its 239 passengers and crew.

The remote controlled submarine has spent the past week scouring the largely unmapped stretch of ocean floor about 2, 000 kilometres northwest of Perth for signs of the plane.

The air, surface and underwater search has narrowed its target range to a 10 kilometre circle of sea floor.

Bluefin-21 is now on its eighth deep sea mission with no sign of wreckage so far.

The search for flight MH370 entered its 44th day on Sunday with the mystery still unsolved.

Hopes for further black box signals are fading as their batteries are now two weeks past their expected 30-day lifespan.

As aircraft and ships again joined the search Malaysian authorities said the operation was at a critical point and asked for prayers for its success.