Oxygen masks were 'inadvertently' deployed, and an emergency announcement played on a United flight — even though everything was fine

• An automated announcement told United passengers to put on oxygen masks during a Transatlantic flight.
• A passenger on the flight told aviation news outlet Simple Flying that some people panicked.

Dozens of United Airlines passengers started to panic when an automated emergency announcement told them to put on oxygen masks, even though there wasn't any danger.

The Boeing 777 was flying from Paris to Washington, DC, last Wednesday when the unusual incident occurred.

Those on board were instructed by a pre-recorded message to wait for oxygen masks to fall from the ceiling and then put them on, Simple Flying reported. Few, if any, masks actually deployed.

A United Airlines spokesperson told Business Insider that "a small number of oxygen masks inadvertently deployed."

Parker Pitman, a passenger on board the flight, told Simple Flying that he couldn't see any masks on the plane. He added that some people tried to force open the ceiling compartments in a panic.

"One person had a panic attack and ran to the aircraft door, presumably to open it," Pitman added. "None of the flight crew nor cabin crew had ever heard the announcement before, and it was a very odd situation."

Travel news site Paddle Your Own Kanoo reported that flight attendants announced that they were struggling to contact the pilots.

Passengers later learned that the 26-year-old aircraft wasn't in trouble after all, and the flight continued on to Washington, DC. Two days later, the plane made its next flight.

The United spokesperson added, "The air pressure in the cabin was normal for the entire flight. The aircraft landed safely as scheduled, and customers deplaned normally."

The airline has faced much scrutiny from regulators this year following a string of safety incidents, like a tire falling off a Boeing 777 and another plane veering off the runway.

United was prevented from launching new routes while it was investigated by the Federal Aviation Administration. Last month, the airline indicated it had been allowed to restart such activities, but the FAA said its review was "ongoing," per the Associated Press.