FBI seeks motive after Seattle mechanic steals plane and crashes on island as family 'devastated'

US investigators are scrambling to understand how a young mechanic was able to steal an empty passenger plane from Seattle’s main airport, fly for more than an hour doing tricks and then crash into a forest, killing himself. 

The FBI, National Transportation Safety Board and Federal Aviation Administration were all attempting to work out how the 29-year-old ground service agent for the airline Horizon Air was able to carry out the incident. 

The 76-seat plane had taken off from Seattle-Tacoma Airport, in the northwestern US state of Washington, on Friday night and was soon accompanied by two F-15 fighter jets which were scrambled into the air. 

Attempts were made over radio transmissions to the convince the pilot - named locally as Richard Russell, who had worked for the airline for three and a half years - to land.  However he ultimately crashed into Ketron Island, a sparsely-populated area of the state.  

Recordings of the conversation between the man and control tower officials captured him sounding excitable, at one point saying he had “a few screws loose” and apologising to his relatives. 

The Pierce County Sheriff's office ruled out terrorism. Ed Troyer, who works at the sheriff’s office, described the man as “suicidal”. 

The White House said in a statement that Donald Trump, the US president, had been briefed on the incident and was “monitoring the situation”. 

"He was a faithful husband, a loving son, and a good friend," the Russell family said in a statement.

"This is a complete shock to us. We are devastated by these events and Jesus is truly the only one holding this family together right now," the family said.

It has raised fundamental questions about airline security at America’s major airports after the mechanic was able to board the plane, taxi onto the runway and take off without being stopped. 

Aviation experts questioned what the authorities would have been able to do if the pilot was determined to fly the plane into a city rather than do loop-the-loops.

Some also asked whether there should be annual mental health checks for all those employed in the airline industry. 

Investigators are expected to want to obtain camera footage from the airport, which hosts more than 30 airlines with nonstop service to more than 90 domestic destination, to understand how the man was able to co-opt the plane in broad daylight. 

They are also expected to want to recover cockpit voice recorder, in case the pilot made any phone calls or spoke to himself during the flight. 

Chilling audio of the conversation between the pilot and the control tower, where airport officials were attempting to get him to land safely, emerged on Saturday. 

At one point someone in the control tower says: “Congratulations, you did that, now let’s turn around that airplane safely and not hurt anybody on the ground.”

The pilot responds: “Alright. Oh damn it, I don’t know man? I don’t want to. I was kind of hoping that was going to be it, you know.”

In another clip the pilot claims to have put fuel in the plane to "to go check out the Olympics" - the Olympic Mountains which lie about 100 miles (160 kilometers) away. But he expressed fears that the fuel was going "quite a bit faster than I expected."

In another section the man is heard saying: “This is probably like jail time for life, huh? I would hope it is for a guy like me.”

Elsewhere, according to The Seattle Times, he says: "I've got a lot of people that care about me. It's going to disappoint them to hear that I did this.”

"I would like to apologise to each and every one of them. Just a broken guy, got a few screws loose, I guess. Never really knew it until now."

Social media users captured footage of the aircraft doing a large loop-the-loop in a clear sky as the sun was setting. 

John Waldron, a witness, told CNN: “I thought they were practising for an air show to be perfectly honest. I had no idea at the time that the aircraft had been stolen from Sea-Tac. I had no idea what was going on at all, honestly.”

Nick Junka, who said he had worked with the mechanic, said: “We have access to these planes all day long. We secure them. This is the most outlandish thing. I worked with this guy. He was a good guy …. I would never have dreamed of this individual doing this. Never.”

Discussing possible motives, Sheriff Paul Pastor said: “Most terrorists don't do loops over the water. This might have been a joyride gone terribly wrong."

Constance von Muehlen, Horizon’s chief operating officer, said in a video statement: “Our hearts are with the family of the individual aboard as well as all our Alaska Air and Horizon Air employees.”