In a recently released Special Bulletin, the UK Air Accidents Investigation Branch (AAIB) brought attention to a peculiar incident involving an Airbus A321 operating from Stansted Airport (STN) on October 4.
This incident highlighted the potential risks posed by high-power lights used during filming events. Several cabin windows on the aircraft sustained damage, and the discovery was made after the aircraft had already taken off on its next flight.
The AAIB is now actively working with the aircraft manufacturer and the operator to develop strategies to manage this risk effectively in the future.
The Flight History
The Airbus A321 in question – Airbus A321-253NX, G-OATW – was slated for a multi-day charter trip, and its crew consisted of three pilots, an engineer, a loadmaster, and six cabin crew members.
On top of the 11 crew members, there were nine passengers aboard, all of whom were either employees of the tour operator or the aircraft operating company.
Shortly after takeoff, several passengers noticed something amiss. The aircraft’s cabin seemed noisier and colder than usual.
As the aircraft climbed through FL100 (Flight Level 100), the loadmaster, seated just ahead of the passengers, made his way toward the rear of the aircraft.
He found that a window seal near the over wing exits was flapping in the airflow, and the windowpane had shifted down. The cabin noise was described as “loud enough to potentially harm one’s hearing.”
Concerned about the situation, the flight crew decided to halt their ascent at FL140 (14,000 feet) and reduce their airspeed.
The engineer and then the third pilot inspected the damaged window. It was unanimously decided that the aircraft should return to Stansted.
The cabin was secured swiftly, and the flight crew initiated a descent, initially to FL100 and later to 9,000 feet.
The aircraft was established in a holding pattern as they completed checklists for an overweight landing, confirmed landing performance, and prepared for the return to Stansted.
The subsequent approach and landing on RWY were uneventful.
Pre-flight Activity: Lights, Camera and Aircraft
The day before this incident, the aircraft was involved in a unique ground activity. It had been used for filming purposes, during which powerful external lights were directed through the cabin windows to create the illusion of a sunrise.
These lights were first beamed onto the right side of the aircraft for around five and a half hours. The illumination was concentrated on the cabin windows just aft of the overwing exits.
Subsequently, the lights were moved to the left side of the aircraft, where they illuminated a similar area for approximately four hours.
The Toll on Aircraft Windows
The aftermath of this incident was rather astounding. Two window assemblies were missing entirely, and the inner pane and seal from a third window had been displaced but were partially retained in the airframe.
The outer pane from another window was discovered shattered near a rapid-exit taxiway during a routine runway inspection following the aircraft’s landing.
Additionally, a fourth window protruded from the left side of the fuselage.
The Science Behind the Damage
Observations made by experts suggest that the windows had suffered thermal damage and distortion due to prolonged exposure to elevated temperatures during the filming activity. This exposure spanned roughly four to five and a half hours.
The intensity of the lights used had unknowingly subjected the aircraft’s windows to excessive heat, causing the thermal damage and distortion that were later discovered.
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