PORTLAND, Ore. — A "credible security threat" caused an Alaska Airlines flight from Everett's Paine Field to be diverted to Portland on Sunday, the airline confirmed to KING 5.
The threat was related to an off-duty pilot, identified as 44-year-old Joseph Emerson, who "unsuccessfully attempted to disrupt the operation of the engines," according to the airline. The captain and first officer quickly responded, Alaska said, and engine power was not lost.
According to the Allied Pilots Association, Emerson tried "to disable the aircraft engines while at cruise altitude by deploying the engine fire suppressions system."
That would cause the engines to "cease operation," according to aviation expert Scott Hamilton.
The flight, which was being operated by Horizon Air, was en route from Everett to San Francisco when the incident occurred. Alaska Airlines owns Horizon.
Emerson was traveling in the flight deck jump seat prior to the incident. When the jump seat - a third seat in the cockpit - is occupied it’s often filled by an off-duty pilot, but the seat can be used by other airline employees or federal safety inspectors.
One of the pilots then told air traffic controllers that Emerson posed a threat and had been removed from the cockpit.
“We’ve got the guy that tried to shut the engines down out of the cockpit. And he — doesn’t sound like he’s causing any issue in the back right now, and I think he’s subdued," one of the pilots said on audio captured by LiveATC.net. "Other than that, we want law enforcement as soon as we get on the ground and parked.”
Paul Stephan, a passenger on board, said he saw the cockpit door open and a man step out and walk unattended to the back of the plane.
According to Stephan, a crew member announced there was an emergency and that the plane would be diverted.
"Everyone was sort of panicking," he said.
Emerson was taken into custody after the flight landed in Portland, the airline said.
The investigation of the incident is being handled by authorities that include the Federal Bureau of Investigation (FBI) and the Port of Portland Police Department.
He was being held Monday on dozens of counts of attempted murder and reckless endangerment, according to the Multnomah County Sheriff’s Office in Oregon.
According to the airline, all passengers on board were able to travel on a later flight.
"We are grateful for the professional handling of the situation by the Horizon flight crew and appreciate our guests’ calm and patience throughout this event," the airline said to KING 5 in a statement.
This is a developing story. Check back for updates.
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