It is really unfortunate that wreckage of missing MH370 has not been found yet despite 10 planes and nine ships in the Indian Ocean working continuously to find anything that may relate to the plane.

According to reports, the British submarine HMS Tireless will soon join the search effort. A similar move is also planned by the United States, but it has not been publicly announced. However, there are reports that the US Navy is likely to secretly search Indian Ocean to find wreckage of the missing Malaysian airliner.

Investigators may require robotic submarines to find the airplane's black box, which is the only key now to unravel the mystery behind the disappearance of MH370.

Unmanned robot subs, or autonomous underwater vehicles (AUVs), played a vital role to search the black box in 2011 from a lost Air France jet, two years after the plane crashed into the Atlantic Ocean.

The crashed jet's skeleton and its black box were located by the AUVs. Black box provides significant insight to researchers to figure out what all went wrong with a plane.

But the search for the Air France plane and the Malaysian jet has many differences, like the ongoing search is being done in a much bigger area compared to the Air France plane. Also, the pieces of wreckage from the French plane were discovered within days of the crash. But, it still took two years for an AUV from the Woods Hole Oceanographic Institution to locate the skeleton of the Air France plane.

"Air France 447 is a bit different from Malaysian Air 370 in that we had a few more clues to work with," said Dave Gallo, who led the Woods Hole search team. It is very important to narrow the search area to make effective use of AUVs in the MH370 search. But the search area can only be narrowed after finding the wreckage.