A commercial plane took off with 2 missing windows and reached 10,000 feet before anyone realized there was a problem

• An Airbus A321 took off from London Stansted with two missing window panes.
• The plane climbed more than 10,000 feet before anyone realized there was a problem.

A commercial plane took off with two missing window assemblies and reached more than 10,000 feet before anyone realized something was wrong, according to the Air Accidents Investigation Branch.

The incident, which involved an Airbus A321, was the subject of a special bulletin released by the AAIB last week, detailing events that took place on October 4.

On October 4, the plane departed from London's Stansted Airport for Orlando International Airport. It was carrying three pilots, an engineer, a loadmaster, six cabin crew, as well as nine passengers, and was scheduled for a multi-day charter, the bulletin said.

But shortly after takeoff, several passengers noticed that the aircraft cabin seemed both colder and noisier than usual, according to the bulletin.

The plane continued to climb to an altitude of 10,000 feet and the seatbelt signs were switched off, according to the bulletin.

It was at this point that the loadmaster walked toward the back of the plane and noticed a significant increase in cabin noise, it said, with the noise "loud enough to damage your hearing."

The loadmaster also noticed that the window seal on a window on the left side of the plane was "flapping in the airflow," the bulletin said.

The flight crew decided to stop the plane's climb at 14,000 feet and reduce airspeed, despite no "abnormal indications" on the flight deck and normal operations of the aircraft's pressurization system, per the bulletin.

An engineer and a pilot were then dispatched to take a look, it said.

It was agreed that the aircraft should return to Stansted, and the plane landed 36 minutes after taking off, the bulletin said.

Once parked, the cabin crew inspected the plane and discovered that two window assemblies — the inner and outer panes and rubber seal — were missing, the bulletin said.

According to The Independent, the only thing in place was the scratch pane, a piece of plastic that prevents passengers from touching the outer window.

The inner pane and seal from a third window had also been displaced, the AAIB said.

It added that the day before the flight, the plane had been used during a filming event where high-power lights were active for up to five-and-a-half hours.

Thermal damage and window deformation were subsequently observed in the area around the overwing emergency exit, which the AAIB attributed to extended exposure to elevated temperatures.

The AAIB said in the bulletin that the incident could have had far "more serious" consequences.

"Whereas in this case the damage became apparent at around FL100 [10,000 feet] and the flight was concluded uneventfully, a different level of damage by the same means might have resulted in more serious consequences," it said.

It's now working with the plane's manufacturer and operator to fully understand the properties of the lights used, and how to mitigate risks in the future, according to the bulletin.

The AAIB did not immediately respond to Insider's request for comment.