The British Airways plane in last week's dramatic emergency at Heathrow landed after pilots shut down one engine and the other engine was on fire, according to an official American accident investigation team.
Engine cowls, or coverings, on both the US-made engines of the Oslo-bound Airbus A319 came off and fell on the runway as the plane took off for Oslo last Friday morning, said the US National Transport Safety Board (NTSB).
The pilots reported that they shut down one engine, there was a fuel leak, and that they were returning, the NTSB said on its website .
The NTSB went on: "The pilots subsequently reported that one engine was shut down and the other engine was on fire."
With passengers on board and witnesses on the ground seeing smoke billowing from the stricken plane, the aircraft landed safely and the 75 passengers and crew were evacuated via emergency chutes.
The drama closed both runways for a while and although both re-opened there were flight cancellations and delays for those heading off for the bank holiday weekend.
The incident is the subject of an investigation by the UK's Air Accidents Investigation Branch (AAIB) who are being assisted by the NTSB as the engines involved are American made.
The NTSB information on its website said: "An Airbus A319-131, registration number G-EUOE, during departure from London Heathrow International Airport, had the engine cowls from both International Aero Engines V2500 engines separate and fall on to the runway.
"The pilots reported that they shut down one engine, there was a fuel leak, and that they were returning. The pilots subsequently reported that one engine was shut down and the other engine was on fire.
"The airplane landed, was shut down, and the passengers were evacuated via the emergency slides."
The NTSB added: " As the state of manufacture of the engines, the NTSB has designated a US accredited representative.... to assist the AAIB with their investigation."