A father-of-three Peter Lynch, 52, and Endah Cakrawati, 30, perished when his Grumman G-73 "Mallard" flying boat broke up on impact after 5pm on Thursday in front of horrified families.
"Sadly, tragically we were unable to rescue these people and they lost their lives," WA Police Acting Commissioner Stephen Brown said on Friday.
Laura Lynch posted a tribute on Facebook confirming the death of the businessman, who's believed to have been working with iron ore miner Fortescue Metals in Perth.
"With great difficulty, I am unbearably saddened to confirm that my great friend and the father of my children passed after a tragic accident on the Swan River in Perth yesterday," the Brisbane- ased mother wrote.
WATCH: Two dead after plane crashes into Perth river
A Linkedin image obtained Friday, Jan. 27, 2017 of Endah Cakrawati.(AAP) Source: AAP
The Great Eastern Fly In committee described Mr Lynch's death as a tragic accident.
"Peter was a man of vision and one with a passion for aviation and was well loved and respected in our close knit flying community," it said.
"Peter for many years attended the Evans Head Great Eastern Fly In, was the man with a vision for an Air Park at Evans Head, and was instrumental in the establishment of the Evans Head Aviation Museum.
"Our deepest and sincere condolences are expressed to Peter's family and many friends who are grieving with his sad passing.
"Clear skies Peter, and may you rest in peace our dear friend and colleague."
Vison taking by shocked witnesses on their phones and posted on social media showed a huge plume of water rising from the river as the plane hit nose first.
"The plane seemed to be banking and then it looked like it was turning too sharply and just seemed to fall into the water," witness Mark Annette-Stuart told AAP.
Up to 10 pleasure craft on the river sped to the scene near Heirisson Island and tried in vain to rescue the occupants.
"His wings were pointing to the sky and to the water and we thought 'this is not good' then we saw it break into two pieces," witness Craig Newill told The West Australian.
Other witness reported a loud bang as the plane entered the water.
The plane was part of an airshow over the river ahead of Perth's annual Skyworks fireworks display, which was cancelled out of respect to the victims and to conserve the integrity of the site.
Opposition leader Mark McGowan said in a statement on Friday that the tragedy had shaken the WA community.
"My heart goes out to the families and friends of the two people involved. They're in all our thoughts and prayers today," he said.
"The decision to cancel the Skyworks yesterday was the right call given the tragic circumstances."
The plane remained in situ overnight guarded by water police but could be removed on Friday pending a decision by the WA Department of Transport and the Australian Transport Safety Bureau.
WA Police acting commissioner Stephen Brown said the cause of the crash was unknown but thankfully no one else was injured.
More than 300,000 people had been expected to attend the Skyworks show around the river.
