Airline employee who stole plane hid in aviation's security blind spot

More details have emerged about how an airline employee stole a plane at one of America's most security conscious airports, Seattle.

And it's raising questions about whether the mental state of airline workers should be checked, not just their criminal records.

Richard Russell, a 29-year- ground-services worker, has been named as the person responsible for stealing and then crashing the Alaska Airlines aircraft.

He used a machine called a pushback tractor to first manoeuvre the aircraft, which was in a maintenance area, so he could board and then take off Friday evening, authorities said.

Astonishing video showed the Horizon Air Q400, a turboprop plane that seats 76 people, doing large loops and other dangerous manoeuvres as the sun set on Puget Sound.

Mr Russell could be heard on audio recordings telling air traffic controllers that he is "just a broken guy".

"I've got a lot of people that care about me. It's going to disappoint them to hear that I did this ... Just a broken guy, got a few screws loose, I guess."

But authorities are still at a loss to explain what drove Russell to commit his crime.

"Until the FBI has the opportunity to get better background on the person, find out what motive they had, it's a little too early to make a determination on what the objective was," said Debra Eckrote of the National Transportation Safety Board.

Last year the US Congress passed a law mandating tougher screening standards for all airport employees - but these security checks don't include psychological checks.

"With regard to mental health, we do do screening in terms of background checking for all airport workers," Transportation Security Administration's David Pekoske told CBS News.

"And really, one of the things that we emphasize, 'if you see something say something,' also applies for insider threats."