‘Suicidal’ employee commandeers aircraft with no passengers on board and it later crashed on an island near Tacoma.

A “suicidal” airline employee stole an Alaska Airlines plane without any passengers on it, performed an upside-down aerial loop, and crashed into an island in Washington state.

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.

Video showed the aircraft doing large loops and other dangerous manoeuvres as the sun set.

The plane was chased by two military F-15 aircraft but they were reportedly not involved in the crash on Ketron Island, southwest of Tacoma, in Puget Sound, which sparked a fire in the dense forest.

The man could be heard on audio recordings telling air traffic controllers he is “just a broken guy”.

Pierce County Sheriff Paul Pastor said the man “did something foolish and may well have paid with his life”.

Witnesses reported seeing the plane being chased by military aircraft near the airport. “Pilots kept plane out of harm’s way and people on ground safe,” the sheriff’s department said.

Officials said the 29-year-old man who stole the plane was “suicidal” and there is no connection to terrorism. Seattle-Tacoma officials said the airline employee had “conducted an unauthorised takeoff without passengers”.

Authorities initially said the man was a mechanic, but Alaska Airlines later said he was an employee who helps direct aircraft to gates and de-ices planes.

‘A few screws loose’

An air traffic controller called the man “Rich”, and tried to convince him to land the plane.

“There is a runway just off to your right side in about a mile,” the controller said, reffering to an airfield at Joint Base Lewis-McChord.

“Oh man. Those guys will rough me up if I try and land there,” the man responded, adding ,”This is probably jail time for life, huh?”

Later the man said: “I’ve got a lot of people that care about me. It’s going to disappoint them to hear that I did this… Just a broken guy, got a few screws loose I guess.”

The plane went down into the sparsely populated Ketron Island. There were no reports of casualties on the ground.

Witness Royal King told The Seattle Times he was photographing a wedding when he saw the low-flying turboprop being chased by two F-15s. He said he didn’t see the crash but saw smoke.

“It was unfathomable, it was something out of a movie,” King said. “The smoke lingered. You could still hear the F-15s, which were flying low.”

The US Coast Guard was sending a vessel to the crash scene.

Horizon Air is part of Alaska Air Group and flies shorter routes throughout the US west. The Q400 is a turboprop aircraft with 76 seats.

“Our hearts are with the family of the individual aboard, along with all of our Alaska Air and Horizon Air employees,” Horizon Air Chief Operating Officer Constance von Muehlen said in a video posted on Twitter.