A man tried open an emergency door and stab a flight attendant with a broken metal spoon before being subdued by fellow passengers who rushed to help on a United flight from Los Angeles to Boston, according to federal prosecutors.
Francisco Severo Torres, 33, was charged with one count of interference and attempted interference with flight crew members and attendants using a dangerous weapon.
Video recorded by a fellow passenger showed a man identified as Mr Torres threatening “kill every man on this plane” and goading anyone to stop him.
Authorities say that 45 minutes before the flight landed in Boston on Sunday, a cockpit alarm went off indicating that an emergency door had been deactivated.
Court documents state the handle was found to have been moved from fully-locked a quarter of the way to unlocked and the emergency slide arming lever had been moved to the “disarmed” position.
A flight attendant secured the door and emergency slide before reporting the situation to the captain.
Another flight attendant then reported that the suspect had been seen near the emergency door and had tampered with it, and when confronted he asked if any cameras had recorded him doing so.
Federal prosecutors say that the flight attendant notified the captain that the suspect was believed to be a threat to the flight and that he should land the aircraft as soon as possible.
Mr Torres is then accused of getting out of his seat and approaching two flight attendants before allegedly trying to stab one of them with a broken metal spoon.
Court documents state that the employee was hit on the neck three times by the suspect.
“Passengers then tackled Torres and he was restrained with the assistance of flight crew. Torres was immediately taken into custody upon the flight’s arrival to Boston,” prosecutors state.
Torres was arrested and made an initial appearance on Monday in US District Court. He was detained and will appear in court again on Thursday.
If convicted Mr Torres faces a maximum prison of life behind bars, five years of supervised release and a fine of up to $250,000.
United Airlines said no one was injured.
“Thanks to the quick action of our crew and customers, one customer was restrained after becoming a security concern on United flight 2609 from Los Angeles to Boston,” a company statement said. "The flight landed safely and was met by law enforcement."
Aircraft doors cannot be pushed open inflight due to cabin pressure.
