An aircraft bound for the United States took flight with missing and damaged window panes and had to abruptly return to its London origin out of safety concerns, the UK’s Air Accidents Investigation Branch said in a special bulletin published on Nov. 3.

According to the bulletin, “several cabin windows” on an Airbus A321 were damaged by “high power lights used during a filming event” and were later discovered when the aircraft’s next flight was already in the air.

The bulletin noted that “more serious consequences” could have taken place if the “window integrity was lost at higher differential pressure.”

The flight took off from London Stansted Airport and was set to land at the Orlando International Airport on October 4. It was carrying 11 crew members and 9 passengers, the bulletin said.

After takeoff, passengers reported that the cabin seemed colder and noisier than it normally would have, according to the bulletin, but it wasn’t until an air crew member on the plane walked toward the back of the cabin and agreed that it was “loud enough to damage your hearing” that the crew realized something was wrong.

The special bulletin said that the crew member’s “attention was drawn to a cabin window on the left side” of the plane and he “observed that the window seal was flapping in the airflow and the windowpane appeared to have slipped down.”

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The crew member then informed others of the missing window, which was discovered when the plane had already climbed to approximately 14,500 feet. The bulletin said that pilots reduced flight speed and stopped climbing as the engineer and third pilot went to check it out. Based on their observation, the crew decided to return to Stansted.

The plane landed safely back at its origin airport and the plane remained “pressurized normally” throughout the duration of the 36-minute flight.

Once the plane was parked, the crew inspected it only to find that there were two missing windowpanes. A third windowpane was “dislodged,” the special bulletin said, and a fourth “protruded from the left side” of the plane.

Investigators determined that the panes faced “thermal damage” after being exposed to intense lighting for four-to-five-hours the day before.

Maxibrute 12 lights were used to simulate a sunrise from inside an aircraft for an unspecified filming event held the day prior, the bulletin said. The lights are supposed to be shone at a distance of 10 meters, but were placed at a distance of anywhere from six-to-nine meters while illuminating the plane.

Investigations into the event are ongoing.