An Airbus A321 aircraft took off from London Stansted Airport last month with four damaged window panes, including two that were missing, according to UK air accident investigators.
Nine passengers and 11 crew members were on board the plane bound for Orlando International Airport in Florida on October 4, when the damage, apparently caused by high-powered lights used during a filming event the previous day, was discovered after takeoff.
The aircraft had reached an altitude of at least 4,000 metres by the time it was turned around, reads a special bulletin by the UK's Air Accidents Investigation Branch (AAIB.) The plane landed back at Stansted Airport safely shortly afterward.
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'Increased cabin noise'
The report, published on November 4, details the incident, noting that it could have resulted in "more serious consequences" if "window integrity" had been "lost at higher differential pressure."
It describes how passengers had noticed that the aircraft appeared to be "noisier and colder than they were used to" after taking off at Stansted Airport.
As the plane continued to climb and the seatbelt signs were switched off, the loadmaster, who had also noticed "increased cabin noise," walked towards the back of the aircraft and spotted a cabin window on the left side of the aircraft with a window seal that was "flapping in the airflow."
The loadmaster, who described the cabin noise as "loud enough to damage your hearing" informed the cabin crew and also went to the flight deck to let the commander know.
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Ongoing investigation
Although there were no "abnormal indications," the crew opted to stop the plane's ascent at 4,000 metres and reduce airspeed while the window was inspected by an engineer and the third pilot.
"Having inspected the window, it was agreed the aircraft should return to Stansted," the report continues.
"The cabin crew told the passengers to remain seated and keep their seatbelts fastened, and reminded them about the use of oxygen masks if that became necessary."
The full extent of the damage to the aircraft wasn't discovered until it was back on the ground.
The flight crew initiated a descent and the aircraft arrived back at Stansted Airport a short while later. The total flight time was 36 minutes, according to the bulletin.
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After passengers had disembarked and the plane was parked and shut down, the crew inspected the plane from the outside, and found that two cabin window panes were missing and a third was dislodged.
A shattered outer pane was later found "during a routine runway inspection" while a fourth window that "protruded from the left side of the fuselage" was also discovered.
"The four affected windows were adjacent to each other, just aft of the left overwing exit," adds the bulletin.
The AAIB explains that the windows may have "sustained thermal damage and distortion" due to increased temperatures when the aircraft was used during filming for four to five and a half hours the day before the flight.
It will continue to investigate the incident to "fully understand the properties of the lights used and how this risk can be managed in future."
"Aircraft owners and operators should consider the hazard posed by such activities to minimize the risk of aircraft damage," it added.
CNN has contacted the AAIB for further comment.
