Fuel leak from over-wing fuel filler cap, en route Heathrow to Chicago, 12 July 2016.
The flight crew were advised that a fuel leak had been observed from the right over-wing fuel filler cap. The crew declared an emergency and diverted to Edinburgh, where the aircraft landed uneventfully. The fuel filler cap was replaced and the aircraft departed Edinburgh the following day, but during the climb a fuel leak was once again observed from the same location on the right wing. The aircraft returned to Edinburgh, where further maintenance investigation revealed a damaged O-ring in the over-wing fuelling port as the cause of the fuel leak.
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Published: 10 November 2016
Date of occurrence: 12 July 2016