British Airways Flight 5390 - Investigation

Investigation

Accident investigators found that a replacement windscreen had been installed 27 hours before the flight, and that the procedure had been approved by the shift maintenance manager. However, 84 of the 90 windscreen retention bolts were 0.026 inches (0.66 mm) too small in diameter, while the remaining six were 0.1 inches (2.5 mm) too short. The investigation revealed that the previous windscreen had been fitted with incorrect bolts, which had been replaced on a "like for like" basis by the shift maintenance manager without reference to the maintenance documentation. The air pressure difference between the cabin and the outside during the flight proved to be too much, leading to the failure of the windscreen. The incident also brought to attention a design flaw in the aircraft of the windscreen being secured from the outside of the aircraft, putting a greater pressure on the bolts than if they were secured from the inside.

Investigators blamed the British Airways Birmingham Airport shift maintenance manager for installing the incorrect bolts during the windscreen replacement and for failing to follow official British Airways policies. They also found fault with British Airways' policies, which should have required testing or verification by another individual for this critical task. Finally, investigators blamed the local Birmingham Airport management for not directly monitoring the shift maintenance manager's working practices.