AAIB investigation to Boeing 777-236, G-YMMU
Fumes on the flight deck, on departure from London Heathrow Airport, 3 July 2019.
Summary:
Shortly after takeoff from London Heathrow the pilots smelt fumes on the flight deck. They donned oxygen masks, carried out the appropriate checklist and returned to Heathrow where the aircraft landed without further incident.
Extensive engineering investigation was carried out and several components were changed, but the source of the fumes was not found.
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