An off-duty pilot riding as a passenger in the cockpit of an Alaska Airlines flight tried to "disrupt the operation of the engines" on Sunday, forcing the flight en route to San Francisco to divert to Portland, Oregon, the airline said in a statement.
The suspect, identified by police as Joseph D. Emerson, 44, was subdued by the flight crew and taken into custody by the Port of Portland police officers, the port said in a separate statement.
Online booking records show Emerson has been charged with 83 felony counts of attempted murder, 83 counts of reckless endangerment and one count of endangering an aircraft.
After taking off from Paine Field Airport in Everett, Washington, Flight 2059 – one operated by Horizon Air, a regional carrier owned by Alaska Airlines – reported a "credible security threat related to an off-duty Alaska Airlines pilot who was travelling in the flight deck jump seat," the airline's statement said.
Pilots will occasionally ride a cockpit "jump seat" when travelling in an official capacity or commuting to another airport.
"The jump seat occupant unsuccessfully attempted to disrupt the operation of the engines," the airline said, adding the captain and first officer "quickly responded" and engine power was not lost.
One of the pilots assigned to the flight is heard in audio recorded by LiveATC.net telling air traffic controllers the suspect had "tried to shut the engines down."
"I think he's subdued," the pilot said. "Other than that, we want law enforcement as soon as we get on the ground and are parked."
The flight was diverted to Portland International Airport, per the airline. It did not name Emerson but said the "jump seat occupant" was in custody and under investigation by the FBI and the Port of Portland.
The Port of Portland confirmed Emerson's identity in a statement to CNN, adding he was held at the Multnomah County Detention Centre and the investigation was ongoing.
Other airlines were briefed on the preliminary details by the FAA.
A memo obtained by CNN indicates the off-duty pilot attempted to cut power to both engines by pulling emergency fire extinguisher handles.
Capt. Mike Karn, senior manager of flight security for American Airlines, said in the memo circulated at his airline the off-duty Alaska Airlines pilot attempted "to disable the aircraft engines while at cruise altitude by deploying the engine fire suppression system."
In a statement, the FBI's Portland field office confirmed it was investigating and said it could "assure the travelling public there is no continuing threat related to this incident." No injuries were reported on Flight 2059, the FBI said.
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The FAA is supporting a local law enforcement investigation, it told CNN. Separately, it informed airlines the incident was not connected to "current world events," a veiled reference to the war in the Middle East between Israel and Hamas.
FAA records show Emerson held an Airline Transport Pilot certification with ratings to fly the Airbus A320, Boeing 737, Canadair Regional Jet, and De Havilland Dash 8. He did not hold a certification to fly the ERJ 175, those records indicate, the type of aeroplane in use during Sunday's incident.
The rest of flight 2059's passengers were able to travel on a later flight, Alaska Airlines said.
"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 in the statement.
