The decision to divert a transatlantic flight over an alleged air rage incident was recommended because there was a potential “time bomb” on board, a court has heard.
Joseph Oka, a United Airlines relief pilot, said he feared the actions of an unpredictable passenger could have been a distraction for something more sinister.
He told Antrim Crown Court: “I was thinking, can this just be a minor incident? Our training is to treat every incident as not minor.
“This could really be a diversion to take attention away from the front.”
The Boeing 777 carrying 264 passengers was en route from Rome to Chicago on June 20 last year when the captain made the decision to touch down at Belfast International Airport after concerns were raised about the behaviour of Jeremiah Mathis Thede.
The Californian, 42, denies a charge of endangering an aircraft or persons in the aircraft.
Mr Oka, a former US navy pilot with 19 years’ experience at United, said he made the unprecedented recommendation to “offload” Thede as the plane approached the end of UK airspace.
To the forefront of his mind was an extreme incident where a passenger on a previous flight had been involved in a prolonged struggle before the plane could land, he said.
“There could potentially be a time bomb on board,” he said.
“Do you want to deal with it on the ground or in the air, given that we were about to coast out?
“There would be a long period for someone to get hurt while trying to get to an airport.”
The relief pilot, who is legally required to sleep during the first three hours of the flight, described being woken twice and asked to deal with Thede, adding: “That never happens.”
Complaints included allegedly “staring” at a female passenger and invading her personal space.
Thede, who had changed his clothes a number of times and was standing up rummaging through his bag in the overhead bin, had been given three warnings to change his conduct, the court was told.
Mr Oka did not witness any inappropriate behaviour but said he believed the accounts of the crew and concerned passengers.
He said: “Another part of our training is that if any passenger’s behaviour or conduct affects the safety or comfort of another passenger, they may be removed – and that was clearly happening.
“I just felt that the crew members’ duties had been interfered with enough, we were reaching the point where we were coasting out and once you are over the Atlantic there are not a lot of places to land.
“It’s better to offload this gentleman and continue with this flight.”
The court heard there was no evidence that Thede’s actions were part of a wider distraction plot and shortly after the captain announced the plane was being diverted he appeared to be asleep.
He was only woken when police officers escorted him off, it was claimed.
It also emerged that although restraints were available they were not deployed.
Previously the court has been told the plane had to dump thousands of litres of fuel before making the unscheduled stop.
And as the crew would have exceeded their legal flying hours if the aircraft had resumed the journey straight away, the passengers were forced to wait almost 24 hours before the plane could take off again, with many having to sleep on the terminal floor.
Throughout proceedings Thede, who was dressed in a navy suit jacket, white shirt and grey trousers, listened intently from the dock, occasionally taking notes.
The trial continues.