The aircraft vanished en route from Kuala Lumpur to Beijing in March 2014, with 239 people on board. Debris has been collected from Indian Ocean islands and Africa's east coast, with at least three pieces confirmed as coming from the missing plane.
One of the world's most advanced undersea search vessels, the Seabed Constructor, set off from Durban, South Africa, on January 3. The search restarted immediately after a US-led team aboard the Seabed Constructor on Sunday reached the remote spot in the Indian Ocean that Australia's scientific agency believes is the plane's resting place.
The team will reportedly be using eight drone-like autonomous underwater vehicles, AUVs, to scour the seabed. Nothing on this scale with this equipment has been attempted before.
"If they don't find anything in the 90 days… I think that would be the end for decades — this is like the final effort, if you like," Charitha Pattiaratchi, professor of coastal oceanography at the University of Western Australia, told Reuters.
Australia, Malaysia and China called off the original two-year search for the plane after finding nothing in a 120,000-sq-km underwater search zone in January last year, despite investigators urging the search be extended to a 25,000 sq km area further to the north.