The mechanic commandeered the Horizon Air Q400 aircraft from Seattle-Tacoma International Airport, and the crash occurred because he was "doing stunts in [the] air or [a] lack of flying skills", the sheriff's department said on Twitter on Friday.
A reportedly suicidal employee at Sea-Tac Airport stole an airplane, flew it to south Puget Sound where he crashed it on Ketron Island Friday night. It noted that normal operations at the airport had resumed.
A plane has crashed in Washington state after a mechanic stole it from the Seattle-Tacoma International Airport, the Pierce County Sheriff's office said.
The plane crashed into Ketron Island, it said. Horizon Air is a division of Alaskan that flies shorter routes in the western US. There appear to have been no passengers on the 76-seat plane.
Video showed the aircraft doing large loops and other unsafe maneuvers as the sun set. "No others involved", the Pierce County Sheriff said. "We are working back ground on him now".
A Horizon Air airplane was stolen from SeaTac Airport on August 10, 2018 and crashed on Ketron Island where it sparked a fire.
John Waldron, who took dramatic video of the stolen plane flying in a loop, told CNN that he was out for an evening stroll when he saw the two jet fighters following the turboprop airplane.
Witnesses told Seattle TV station KIRO that they saw the plane accompanied by two military aircraft before what they thought was a crash.
Sheriff Paul Pastor said during a news conference in Steilacoom.that the pilot was "probably deceased".
"We're just trying to find a place where you can land the plane safely", the controller says.
SeaTac confirmed the plane crashed after being piloted by an employee.
Communication between the hijacker and Air Traffic Control- "I've got a lot of people that care about me".
Ms Morse said her mother, who lives near the crash site, had said eight minutes later that her whole house shook.
A plume of smoke has been seen near Ketron Island, Washington, the US Coastguard reported.
This is a developing story and will be updated as more information becomes available.