Air Accidents Investigation Branch (AAIB) analysts found that the Airbus’ acrylic windows had shrunk after being exposed to “high intensity” lights used for filming an advert the previous day.
Advertisers were on board the aeroplane at Stansted the day before the incident to film promotional footage.
Film technicians positioned high-intensity halogen lights outside the airliner’s fuselage, shining in through the windows to create a sunrise effect.
The six lights used had a combined lighting capacity of 72,000 watts – more than seven hundred times greater than a household light bulb.
The AAIB said: “The lights were first shone on the right side of the aircraft for approximately five and a half hours, with the light focused on the cabin windows just aft of the overwing exits.
“The lights were then moved to the left side of the aircraft where they illuminated a similar area on the left side for approximately four hours.”
Technicians placed the lights between six and nine metres from the Airbus’ windows.
Data from the light manufacturer suggested that surfaces six metres away could see temperatures rise by as much as 64C.
No information was given by the AAIB about who the advertiser was.
Airliner windows have two panes: a tough outer pane designed to withstand extreme temperatures and pressures, and an inner “scratch pane” on the passenger side.
“All the scratch panes remained in place so there was no direct, unrestricted aperture between the passenger cabin and the outside air,” said the AAIB.
A Titan Airways spokesman said: We would like to thank the members of the AAIB team for their extremely thorough and professional investigation. The aviation industry as a whole will benefit from the lessons learnt from this event.
“We are also pleased to hear that our colleagues at Airbus will be circulating further information to its worldwide customer base, highlighting the potential damage that can be caused by high-intensity lighting.
“We are also grateful to all of our crew members onboard, whose swift and professional handling of the incident was exemplary.”
The airliner was registered G-GBNI while it was being used for royal and Government flights. At the time it was painted white with a Union flag logo on the tail.
After the Government charter ended, the Airbus was re-registered G-OATW and repainted in a black colour scheme.