The off-duty pilot accused of trying to cut off fuel to the engines of an SFO-bound commuter jet on Sunday, endangering the lives of 83 people, is set to make his first court appearance today in Portland, and federal investigators appear to already be sharing what they've learned about his motives.

44-year-old Bay Area resident Joseph David Emerson is scheduled to appear in Multnomah County Superior Court in Portland, Oregon at 2 p.m., as KTVU reports. He faces 167 counts, including 83 counts of attempted murder, for his seemingly unhinged, alleged actions in the cockpit of a Horizon Airlines jet on Sunday — where he was riding on the jump seat, likely commuting home to SFO from working other flights for parent company Alaska Airlines.

We have a few new details now about what transpired in the cockpit. Alaska Airlines officials have explained that Emerson tried to shut down the plane's engines by "trying to deactivate the fire suppression system." Luckily, the pilot and first officer acted quickly and prevented the engines from losing power — officials said they were able to "reset the T -handles" to make sure that the fuel was never shut off, per KTVU.

Federal investigators now say that Emerson was high on magic mushrooms when he took the jump seat back to SFO — and this was apparently his first time ever doing them? As the Chronicle reports, Emerson allegedly said in an interview, "Yah… I pulled both emergency shut off handles because I thought I was dreaming and I just wanna wake up."

Update: Following his court appearance, we now know via the Associated Press that Emerson waived his right to an attorney, and said upon his arrest by the Port of Portland Police, "I'm admitting to what I did. I'm not fighting any charges you want to bring against me, guys."

Pilots and other flight crew said there was absolutely no indication that anything was amiss with Emerson when he boarded the plane, and he engaged in polite conversation about the weather and his career at Alaska Airlines, the AP reports. But an hour into the flight he reportedly ripped his headset off and said, "I'm not OK," and that is when the approximately 90-second altercation began. He would then instruct a flight attendant to cuff him when he was led out of the cockpit, allegedly saying, "You need to cuff me right now or it's going to be bad."

A flight attendant also reported having to restrain Emerson from reaching toward the handle of an emergency door as they were descending into Portland.

ABC 7 spoke to a passenger who was sitting in the rear of the plane who witnessed the aftermath of the incident, when Emerson was led back to a seat with his hands bound with zip ties.

"I saw zip ties [as he walked past], which was confusing because they had told us it was a medical emergency," says passenger Aubrey Gavello, speaking to ABC 7. She describes seeing Emerson seated nearby (but she apparently did not see him grab for the emergency door).

"He was tall, well kempt, had a [employee] lanyard, shirt tucked in, well put together," Gavello says. She heard a flight attendant telling him, "You're going to be OK," and she adds, "He looked dead in the eyes almost. It was almost as if he had a psychotic breakdown."

Gavello's boyfriend, seated in seat 1A at the front of the plane, slept through the entire ordeal, and Gavello says, "That tells you how calm it was."

After the plane made an emergency landing in Portland and Emerson was escorted off by law enforcement, Gavello says the the flight attendant came on the PA to explain that he had had "a mental breakdown."

We learned Monday that Emerson is a father of two, married, and lives in the East Bay town of Pleasant Hill.  Neighbors spoke to reporters Monday and expressed their shock, saying that by all accounts, no one saw anything like this coming, and there was no evidence of conflict at the home.

The Chronicle reports, via the FBI interview, that Emerson said he began feeling depressed about six months ago, and the mushroom experimentation seems to have something to do with that.

Per the AP, in his interviews with law enforcement, Emerson "admitted to feeling dehydrated and tired" and said he had not slept in about 40 hours.

KTVU reports that Emerson became a captain at Alaska Airlines in 2019, after being a First Officer with the airline upon its acquisition of Virgin America in 2016. He started out at Alaska Air Group as a Horizon First Officer in August 2001, but he left Horizon in 2012 to join Virgin America as a pilot.

It remains to be seen if Emerson may face federal charges in addition to those likely to be filed in state court in Oregon. The FBI, the Transportation Security Administration, and the Federal Aviation Administration are all reportedly investigating the incident.

Previously: San Francisco-Bound Alaska Airlines Flight Makes Emergency Landing After Off-Duty Pilot Disrupts Engines

Photo: Miguel Angel Sanz

This post has been updated with new information from Emerson's court appearance.