Off-duty pilot who tried to cut engines took mushrooms for 1st time before flight, complaint says

PORTLAND, Ore. -- An off-duty pilot who allegedly tried to shut down the engines on a Horizon Air flight told police he was suffering from depression, had not slept in 40 hours and had taken psychedelic mushrooms for the first time before the flight, according to court documents.

State prosecutors in Oregon filed 83 counts of attempted murder against Alaska Airlines pilot Joseph David Emerson, 44, on Tuesday just before he appeared in court, with his attorney, Noah Horst, entering not guilty pleas on his behalf. Federal prosecutors meanwhile charged Emerson with interfering with a flight crew, which can carry up to 20 years in prison.

RELATED: Alaska Airlines passengers describe off-duty pilot's demeanor, moments leading up to arrest

Passengers who were onboard Alaska Airlines describe what led up to the off-duty pilot arrest after he allegedly tried to shut down the engines.

According to a probable cause statement filed in Multnomah County Circuit Court, Emerson told Port of Portland police following his arrest that he had been struggling with depression, that a friend had recently died and that he had taken psychedelic mushrooms about 48 hours before he attempted to cut the engines. He also said he had not slept in more than 40 hours, according to the document.

Police reported that Emerson did not appear to be intoxicated at the time of the interview, and in a statement Tuesday, Alaska Airlines, which owns Horizon, said neither the gate agents nor flight crew noticed any signs of impairment that might have barred him from the flight. An FBI agent wrote in a probable cause affidavit in support of the federal charge that Emerson "said it was his first-time taking mushrooms."

Emerson, an Alaska Airlines pilot from Pleasant Hill, was arrested Sunday night after the flight crew reported that he tried to cut the engines of the plane by pulling on the fire-extinguisher handles - known as the "T handles."

RELATED: What we know about off-duty Bay Area pilot accused of trying to shut down engines of SF-bound flight

Here's what we know about Joseph David Emerson, the pilot accused of trying to shut off the engines of an Alaska Airlines flight.

Federal officials tell ABC News Emerson was overwhelmed by the flight crew and subdued. He was then handcuffed to a seat, as the flight was diverted to Portland, Oregon. However, during the plane's descent he tried to grab the handle of an emergency exit, according to the document. A flight attendant stopped him by placing her hands on top of his, it said.

The captain and first officer told police after the plane landed that Emerson said "I'm not OK" just before he reached up to pull the handles. They were able to stop him before he pulled the handles all the way down, the affidavit said.

Emerson walked calmly to the back of the plane after being told to leave the cockpit and told a flight attendant, "You need to cuff me right now or it's going to be bad," the affidavit said. Another flight attendant heard him saying, "I messed everything up" and "tried to kill everybody."

According to the affidavit, he asked police if he could waive his right to an attorney: "I'm admitting to what I did. I'm not fighting any charges you want to bring against me, guys."

Alaska Airlines largely confirmed what the Department of Justice said in its complaint about Emerson's actions on flight 2059, saying after reviewing the document it's "deeply disturbed by what we have learned."

The airline said in a statement its gate agents followed FAA-mandated practices to authorize a jump-seat passenger, confirming that Emerson was an off-duty pilot with Alaska Airlines.

Alaska said its gate agents and flight attendants are trained to identify signs and symptoms of impairment and that "at no time during the check-in or boarding process did our Gate Agents or flight crew observe any signs of impairment that would have led them to prevent Emerson from flying on Flight 2059."

Here's the Air Traffic Control audio recording moments after off-duty pilot allegedly attempted to shut down an Alaska Airline plane's engines.

Alaska Airlines told ABC News that Emerson has since been removed from service indefinitely and relieved from all duties at Alaska Airlines.

"We are deeply proud of our Horizon flight crew and their quick actions both in the flight deck and in the rear of the aircraft," the airline said. "Working together, consistent with their training, they performed their critical roles exceptionally well, representing the best of their profession."

The Associated Press contributed to this report