Incident: Horizon E175 near Portland on Oct 22nd 2023

A Horizon Airlines Embraer ERJ-175 on behalf of Alaska Airlines, registration N660QX performing flight QX-2059/AS-2059 from Everett,WA to San Francisco,CA (USA) with 84 people on board, was enroute at FL310 about 40nm southwest of Portland,OR (USA) when the crew decided to turn around and divert to Portland. The crew advised ATC that there had been a threat on board of the aircraft, the threat was now in the back of the cabin, and stated upon query by the controller, that the threat level reached level 4 (editorial note: according to FAA threat levels this means "attempted or actual breach of flight crew compartment"), law enforcement was needed upon arrival. The crew mentioned the guy that had tried to shut the engines down was put out of the cockpit. The aircraft landed safely on Portland's runway 28L about 20 minutes after leaving FL310.

The airline reported: "On Oct. 22, Alaska Airlines Flight 2059 operated by Horizon Air from Everett, WA (PAE) to San Francisco, CA (SFO) reported a credible security threat related to an authorized occupant in the flight deck jump seat. The crew secured the aircraft without incident. Following appropriate FAA procedures and guidance from air traffic control, the flight safely diverted to Portland International Airport. The event is being investigated by law enforcement authorities." The airline subsequently added: "The Horizon Captain and First Officer quickly responded, engine power was not lost, and the crew secured the aircraft without incident." and further stated: "Fortunately some residual fuel remained in the line, and the quick reaction of our crew to reset the handles restored fuel flow and prevented fuel starvation."

Portland's Police arrested a male individual (44), identified as an off-duty Alaska Airlines Pilot, on charges of 83 counts of attempted murder, one count of endangering an aircraft and other charges of reckless endangerment (a total of 167 counts).

The FAA reported a significant security event when a jump seat passenger attempted to disable the aircraft engines at cruise altitude by deploying the engine fire suppression system, the crew was able to subdue the passenger and remove him from the flight deck.

According to information The Aviation Herald received the jumpseat was occupied by a deadheading pilot, who attempted to shut both engines (CF34) down.

A replacement ERJ-175 registration N651QX reached San Francisco with a delay of about 2:45 hours.

The occurrence aircraft remained on the ground in Portland about 19.5 hours before returning to service.

According to court documents the off duty pilot admitted to police that he pulled both fire handles and stated he had not slept for about 40 hours, felt dehydrated and tired. He had become depressed about 6 months ago, but had not taken any medication, however, had for the first time taken some psychedelic mushrooms. According to testimonies by witnesses and the off duty pilot, everything was okay during the initial stages of the flight, then the off duty pilot said several times he was not feeling okay, threw his headset across the cockpit and subsequently pulled both fire handles down believing he was dreaming and wanted to wake up. The two pilots on duty subdued the off duty pilot, physically engaging with him for about 25-30 seconds before the off duty pilot stopped resisting. About 90 seconds elapsed between the first "I am not okay" and the off duty pilot leaving the cockpit. Flight attendants reported the off duty pilot told them he had just been thrown out of the cockpit and needed to be handcuffed right now or it's going to be bad. Flight attendants did handcuff him. Flight attendants observed him using his mobile phone texting he had just endangered 84 lives including his own. Via his solicitor the off duty pilot pleaded not guilty on all federal charges including 83 counts of attempted murder.

In 2018 Horizon lost one of their Dash 8s after an individual stole and crashed the aircraft, see Crash: Horizon DH8D at Ketron Island on Aug 10th 2018, stolen aircraft crashed into forest.