An off-duty Alaska Airlines pilot in a cockpit jump seat on a US commercial flight was charged with attempted murder for trying to shut down the plane's engines.
A Horizon Air Embraer E-175 was flying from Everett, Washington, to San Francisco when the incident occurred Sunday.
The 80-person jet was rerouted to Portland, Oregon, where it landed safely.
Alaska Airlines stated Horizon Air pilots reported a "credible security threat related to an off-duty Alaska Airlines pilot who was traveling in the flight deck jump seat."
Horizon Captain and First Officer responded immediately, engine power was preserved, and the aircraft was secured.
The airline did not identify the off-duty pilot, but the Multnomah County Sheriff's Office in Portland accused 44-year-old Joseph Emerson with 83 attempted murder charges on Monday.
Live ATC, a website that archives pilot-air traffic controller exchanges, posted the Horizon Air pilot's account of the incident.
A pilot deliberately crashed a Germanwings flight from Barcelona to Dusseldorf in March 2015, killing 144 passengers and six staff.