An off-duty pilot tried to disrupt an Alaska Airlines flight's engines before being subdued, airline says

An off-duty pilot riding as a passenger in the cockpit of an Alaska Airlines flight Sunday tried to "disrupt the operation of the engines," forcing the flight en route to San Francisco to divert to Portland, Oregon, the airline said in a statement Monday.

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 traveling in the flight deck jump seat," the airline's statement said.

Pilots will occasionally ride a cockpit "jump seat" when traveling in an official capacity or commuting to another airport.

Alaska Airlines told CNN the off-duty pilot attempted to shut down both engines by pulling the Embraer 175's engine fire extinguisher handles. The quick reaction of the captain and first officer kept the engines from failing completely, the airline said.

"The fire suppression system consists of a T-handle for each engine; when pulled, a valve in the wing closes to shut off fuel to the engine," Alaska Airlines said in a statement to CNN. "After they are pulled, some residual fuel remains in the line, and the quick reaction of our crew to reset the handles restored fuel flow and prevented fuel starvation."

The plane was at cruise altitude when the incident occurred, Capt. Mike Karn, senior manager of flight security for American Airlines, said in the memo circulated at his airline, which also discussed the alleged attempt to cut engine power.

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 Center and the investigation was ongoing.

Other airlines were briefed on the preliminary details by the FAA.

In a statement, the FBI's Portland field office confirmed it was investigating and said it could "assure the traveling public there is no continuing threat related to this incident." No injuries were reported on Flight 2059, the FBI said.

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 airplane in use during Sunday's incident.

A neighbor said Emerson's alleged behavior was very shocking.

"He seems like a really nice guy. Nothing abnormal about him," Ed Yee told CNN outside his house.

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.

CNN's Jeffrey Kopp and Steve Almasy contributed to this report.