A plane took off from Stansted Airport with missing windows due to damage caused by high-powered lights during a filming event.
The Air Accidents Investigation Branch (AAIB) said the Airbus A321 jet, previously used by the Government, returned to the Essex airport after a crew member discovered the issue early in the flight last month.
It warned the incident could have resulted in “more serious consequences”.
An inspection revealed two cabin windowpanes were missing and two others were out of position.
For the missing windowpanes, the only object filling the space was the scratch pane, which is a cosmetic piece of plastic designed to prevent passengers touching the outer panes.
The aircraft was operated by Titan Airways and used by TCS World Travel, a US-based luxury holiday company.
The incident happened a day after it was used for filming on the ground, when powerful lights were set up close to the plane to “give the illusion of a sunrise”, the AAIB said in a preliminary report.
They shone on the right side of the aircraft for around five-and-a-half hours, before being moved to the left side for four hours.
The AAIB said the lights were designed to be deployed no closer than 10 metres from the object being illuminated, but they were between six metres and nine metres from the damaged windows.
It did not disclose what the filming event was for.
The plane took off for the positioning flight to Orlando, Florida, on 4 October with 11 crew and nine passengers, who were all employees of the tour or aircraft operator, the report said.
The passengers sat together in the middle of the plane.
After take-off and the seatbelt signs being switched off, a crew member walked towards the back of the aircraft and spotted that the seal around one of the windows was “flapping”, the AAIB said.
He reported this to the crew who decided the plane should return to Stansted, where it landed safely.
It reached an altitude of 14,500 feet during the flight.
The AAIB said “the cabin had remained pressurised normally”.
An examination of the area around the missing or damaged windows found foam used to hold them in place had either melted due to high temperatures or was missing.
The damaged windowpanes were “deformed and shrunk[en]”, the AAIB said.
In conclusion, the report said: “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, especially if window integrity was lost at higher differential pressure.”
Titan Airways and TCS World Travel have been approached for comment.
