The plane debris which washed up on Reunion Island will be sent to France for experts to confirm if it is from Malaysia Airlines flight MH370.
A serial number found on it is the key to determining whether it's from the missing plane. There is no doubt that the wing flap found on the small island east of Madagascar is from a Boeing 777, and the only missing plane of that type is MH370.
The proof is in a component code found inside the flap: 657 BB. It corresponds to a Boeing 777 part listed in the manual as a trailing edge wing 'flaperon', which sits on the back of the wing.
Australian Transport Safety Bureau chief commissioner Martin Dolan says its highly likely the wreckage is from MH370.
"We're becoming much more positive that it is associated with MH370, although it remains to be confirmed."
Less certain is the source of this suitcase, also washed up on the island. It's tattered and torn, but doesn't appear to have been in the water for more than a year.
Mr Dolan says it's unlikely the two washed up objects are related.
"Much less optimistic about that suitcase, there's no obvious physical evidence it's been in the sea a long time."
But they are confident about where they've been searching off the southwest coast of Australia. Drift modelling shows debris could've been pushed to the other side of the Indian Ocean.
Aviation expert Richard Quest says in 16 months, debris could have floated anywhere.
"It always said debris could always end up on the western side of the ocean, but for the moment this still remains the most probable search zone."
Experts including oceanographer Erik Van Sebile say there's still a lot of work to do.
"You have to realise that the debris field by now after 17 months is probably the size of Texas. It's an enormous span, and there isn't a lot of debris because a lot of it has probably sunken down."
MH370 vanished on March 8, 2014, while flying from Kuala Lumpur to Beijing. In total, 239 passengers and crew disappeared.
Relatives hope this is a clue to their resting place, and Mr Dolan agrees. He says the families of the victims have waited long enough for answers.
"We are very much conscious of people who have suffered getting the answers they need."
A dozen Malaysian air crash investigators have arrived on Reunion Island. They'll supervise the transfer of the debris to France, and lead the search for any more.