An expert on underwater searches says he is sure that search teams will succeed in finding a Malaysian jetliner that has been missing since March 8, and is believed to be at the bottom of the Indian Ocean.

"I have absolute confidence it will be found. It will take time, but it will be found," oceanographer Chari Pattiaratchi told CBC News.

Flight MH370 went missing en route from Kuala Lumpur to Beijing. After an extensive search, pings from the Boeing 777's black boxes were detected from the seafloor in an area of the Indian Ocean about 1,600 kilometres northwest of Perth, Australia. However, no new signals have been heard since April 8.

Robotic submarines have since been sent to search the seafloor. However, a first attempt was stopped after the sub went past its depth limit of 4.5 kilometres, and a second attempt was cut short by technical problems this week.

But Pattiaratchi, a University of Western Australia researcher who has been involved in a number of deep-water explorations, said he's still confident that the search will find what it is looking for.

MH370 Malaysian Airlines

The search area for the missing Malaysian jet proved too deep for the robotic submarines deployed earlier this week. (Lt. Kelli Lunt/ustralian Defence Force/The Associated Press)

"The important thing to remember is that the depth is a challenge, but the biggest challenge has been overcome," he said. "We have found the pings … that is proof beyond doubt that the plane is there."

While there is no light at all below a depth of 200 metres, Pattiaratchi says the submarines should have no trouble finding the wreckage with their sonar.

The device emits sound waves and listens for how they sound as they bounce off different surfaces. The waves should reflect very differently off the metal body of a plane than natural materials such as silt, Pattiaratchi said. He added that provided the pieces of the plane are larger than a doormat, they shouldn't end up buried in the mud of the ocean floor.

Time the biggest challenge, expert says

One of the challenges in this search is that the submarines are working at the limit of the depth they can handle, Pattiaratchi said. At that depth, the pressure experienced by the subs is 450 times the pressure at the surface.

That also means if any bodies are found in the wreckage, they will have been crushed beyond recognition – something the families of the passengers should be prepared for, Pattiaratchi said.

But the biggest challenge of all is time, he added.

Even if the sub were working all the time, it would still take up to 30 days to cover the entire search area, he estimated.

"There is an urgency because the families would like to have closure," he said. "But the facts of working in the ocean in depths like this is it is a very slow process."

Australian Prime Minister Tony Abbott, whose country is leading the search, told the Wall Street Journal Wednesday that the robotic subs should complete their search in a week or so.

"If we don't find wreckage," he added, "we stop, we regroup, we reconsider."

MH370 search map

MH370 search map (CBC News)