SEATTLE -- Authorities say the man who stole an empty Horizon Air turboprop plane from Sea-Tac International Airport in Seattle was a 3.5-year Horizon employee and had clearance to be among aircraft.
Authorities on Saturday also say the 29-year-old man used a machine called a pushback tractor to first maneuver the aircraft so he could board and then take off Friday evening.
The man didn't have a pilot's license, and authorities say it's unclear how he attained the skills to do loops in the aircraft before crashing about an hour after taking off into a small island in the Puget Sound.
Authorities say the man went through various background checks to get clearance to be in the secured area.
Listen to the conversation between the man and the control tower in the clip below.
The 29-year-old ground service agent died, the Pierce County Sheriff's Department said, without further identifying him.
The 76-seat Horizon Air turboprop plane took off without authorization around 8 p.m. local time, with an unauthorized Horizon Air employee at the controls, airport officials tweeted.
After "doing stunts in (the) air" -- or being flown without proper skills -- for about an hour, the plane crashed at Ketron Island, the sheriff's department said. The man was a ground service agent, a job that includes directing aircraft for takeoff and gate approach, and de-icing planes, authorities said.
The incident, which the FBI's Seattle office said was not considered terrorism, raises questions about security at the airport, including how the man was able to get aboard the plane by himself, CNN safety analyst David Soucie said.
"There is a protocol to not allow anyone singularly to get onboard an aircraft," Soucie said. "If you're going to access the aircraft ... you make sure that you check with someone else, and that someone else (will confirm) that ... you have the right authority to get onto that aircraft."
"Every airport in the country is going to be looking" at whether current protocols need to be changed, Soucie said.
'I would like to apologize ... got a few screws loose'
In audio recordings of the incident posted on Broadcastify, the man can be heard talking to air traffic controllers as they try to guide him to land the plane.
At one point, he apologizes and says he is a "broken guy" with "a few screws loose."
"I've got a lot of people that care about me, and it's going to disappoint them to hear that I did this," the man says. "I would like to apologize to each and every one of them. Just a broken guy, got a few screws loose, I guess. Never really knew it until now."
The sheriff's department described the man as suicidal. It did not elaborate.
Earlier in the flight, the man says: "This is probably like jail time for life, huh? I mean, I would hope it is, for a guy like me."
"Well," a controller responds, "we're not going to worry or think about that. But could you start a left-hand turn, please?"
Later, a controller discusses getting a pilot on the radio to help the man control the aircraft.
"Nah, I mean, I don't need that much help. I've played some video games before," the man responds.
Also, there was this exchange:
"Congratulations," an air traffic controller says, "you did that, now let's try to land that airplane safely and not hurt anybody on the ground."
The man responds: "Awwww-right ... dammit.. I don't know man! I don't know! I don't want to. I was kinda hoping that was gonna be it. Ya know?"
F-15 jets chased the plane
Within minutes of the plane's takeoff, the military scrambled two F-15 jets from Oregon to follow it, authorities said. They pursued the aircraft before it went down on Ketron Island, between Tacoma and Olympia.
F-15 "pilots kept plane out of harms way and people on ground safe," the sheriff's office tweeted. The jets were not involved in the crash, it said.
Washington Gov. Jay Inslee thanked the fighter pilots for keeping residents safe.
"Those pilots are trained for moments like tonight and showed they are ready and capable," he said in a tweet.
Witness thought it was an air show
Witnesses described the surreal scene after the plane left the airport. John Waldron was walking along a trail near the bay when he noticed the two military jets following a plane that appeared to be doing acrobatics.
"I thought they were practicing for an air show," he said.
After the plane approached Ketron Island, Waldron saw a thick column of smoke followed by a loud explosion, he said.
"Everyone was literally frozen in place, muttering about what possibly happened," he said.
Kethleen Reichel said she watched the planes pass by for about two minutes.
"My husband and I are recently former Boeing employees, and we were wondering why a jet was near the passenger airplane," she said. "We heard the jet because our windows were down while we were waiting in the ferry line to go to Anderson Island, which is adjacent to Ketron Island."
Federal agencies are investigating
The plane was taken from a maintenance position and was not scheduled for a passenger flight, said Gary Beck, Horizon Air's president and chief executive officer.
It crashed about an hour after it was stolen and did not hit any ground structures.
"Our hearts are with the families of the individual aboard as well as all of our Alaska Air and Horizon Air employees," said Constance von Muehlen, the airline's chief operating officer.
The regional airline, based at the Seattle-Tacoma airport, is owned by the Alaska Air Group.
Several federal agencies are investigating the incident, said Brad Tilden, the chief executive officer of Alaska Air Group.
"We're working to find out everything we possibly can about what happened, working with the Federal Aviation Administration, the Federal Bureau of Investigation, and the National Transportation Safety Board. We are giving those investigators our full support and cooperation," Tilden said in a statement.
President Donald Trump was briefed on the incident and is monitoring the situation, White House Press Secretary Sarah Sanders said Saturday morning.
Normal operations at the airport were interrupted briefly, the airport said.
The plane was a Q400, a Bombardier turboprop plane, one of about 40 the airline has in its fleet.AlertMe