In March 2014 Malaysia Airlines flight 370 disappeared.
The plane was carrying 239 passengers and crew from Kuala Lumpar to Beijing when it vanished over the south Indian ocean. Everyone on board is presumed dead.
Now a team of mathematicians from Texas A&M University at Qatar think they have solved one of aviation's biggest mysteries.
The research, published in Notices of the American Mathematical Society, used computer simulations to model what could have happened to MH370.
The team suggests the plane nosedived into the Indian ocean at a 90 degree angle, which means it would have sunk to the bottom of the ocean in under a minute. That explains why rescuers did not find any debris or oil near to where they believe the plane crashed.
"The true final moments of MH370 are likely to remain a mystery until someday when its black box is finally recovered and decoded," lead author Professor Goong Chen said. "But forensics strongly supports that MH370 plunged into the ocean in a nosedive."
More: The full paper