A passenger who helped restrain a man who tried to open a plane door on a flight from Los Angeles to Boston said the drama was over in seconds thanks to teamwork.

Simik Ghookasian sat several rows behind the man who, prosecutors say, quietly tried to open an emergency door before trying to stab a flight attendant with a broken metal spoon.

“I heard the guy getting louder and louder and I thought it was just an argument, but he started yelling and screaming and threatening people, threatening to kill them,” said Mr Ghookasian, an LA government contractor flying to Boston on United Flight 2609 on Sunday for work.

Until the shouting, he had not noticed anything unusual about the man, who federal authorities have identified as Francisco Severo Torres.

Mr Ghookasian said he saw the broken spoon, which consisted of the handle with the bowl portion removed, and was among five or six passengers who piled on Torres and removed the makeshift weapon from his grasp.

“That guy was really strong and was really resisting,” he said. “We had a hard time holding him down. It was total teamwork.”

Mr Ghookasian asked a flight attendant for some cable ties or duct tape and the flight attendant produced cable ties.

Mr Ghookasian, who said he has first aid and counter-terrorism training, said he did not have time to be scared – he just reacted and used his instincts.

“Everything just exploded in a few seconds,” he said.

Torres, 33, of Leominster, Massachusetts, was arrested when the plane arrived in Boston and charged with interference and attempted interference with flight crew members and attendants using a dangerous weapon, federal prosecutors said.

He was detained pending a hearing scheduled for Thursday.

An email seeking comment was sent to his federal public defender and a voicemail was left.

The plane was about 45 minutes from Boston when the crew received an alarm that a side door on the aircraft was disarmed, according to court documents.

A flight attendant noticed the door’s locking handle had been moved. Another noticed Torres was seen near the door and believed he had moved the handle.

Airplane doors cannot be opened once in flight due to cabin pressure.

The crew told the captain Toress was a threat and the plane should be landed as soon as possible, authorities said.

Torres then approached two flight attendants, according to court documents.

One of the flight attendants felt the metal object in Torres’s hand hit him on his shirt collar and tie three times.

Torres told investigators he went into the airplane’s bathroom and broke a spoon in half to make a weapon, prosecutors said in the papers.

They say he told authorities he wanted to open the door so he could jump out of the plane.

Investigators said Torres admitted knowing that if he opened the door many people would die.

Torres said the flight attendants confronted him and he stabbed one of them in an attempt to defend himself, according to investigators.

They said he believed the flight attendant was trying to kill him.

Authorities did not say where Torres got the spoon but rules allow airline passengers to take metal utensils except knives on to planes.

United Airlines said no one was hurt.

If convicted, Torres could face life in prison.