The report said the BA plane had undergone scheduled maintenance the night before the incident, which required opening the fan cowl doors on both engines to check oil levels.
The report noted that the plane manufacturer Airbus had recommended airlines strictly adhere to maintenance standards following previous instances of fan cowl door separation on the A320 "family" of planes, which include the A319 in last week's incident.
The report said that last July Airbus said there had been 32 reported fan cowl door detachments.
On some occasions, significant damage was caused to the aircraft but none of those events resulted in a fire.
"The source of ignition that led to the in-flight fire is still under investigation," the AAIB said.
It has been revealed there were 32 other incidents of aircraft engine doors falling off according to today's safety report.
Airlines are being told of the dangers and to ensure they meet proper maintenance procedures.
The report says: "This event has shown that the consequences of fan cowl door detachment are unpredictable and can present a greater risk to flight safety than previously experienced."
Of the previous incidents is says: "80% occurred during the take off phase of flight. On some occasions significant damage was caused to the aircraft, however, none of these events had resulted in a subsequent engine fire."
An interim report into the incident at Heathrow last week in which a plane made an emergency landing says poor maintenance is to blame.
Doors that cover both engines were "left unlatched during maintenance" says the report from air investigators at Farnborough.
Both of the fan cowl doors came off after the plane left Heathrow but one punctured a fuel pipe causing a fire and the emergency.
The report says: "Fan cowl doors from both engines detached puncturing a fuel pipe on the right engine and damaging the airframe, and some aircraft systems.
"The flight crew elected to return to Heathrow. On the approach to land an external fire developed on the right engine. The left engine continued to perform normally throughout the flight. The right engine was shut down and the aircraft landed safely and was brought to a stop on Runway 27R."
A full-scale emergency was declared after the A319 plane took off. It had 75 passengers and was heading to Oslo.
The report continues: "The emergency services quickly attended and extinguished the fire in the right engine. The passengers and crew evacuated the aircraft via the escape slides, without injury."
Keith Williams, BA chief executive, said: “We welcome the publication of the AAIB interim report. We continue to cooperate fully with the investigation team and can confirm that appropriate initial action has already been taken in accordance with the AAIB's safety recommendation to Airbus.
"We regret we are precluded from releasing or discussing any additional details while the AAIB investigation is ongoing. We commend the professionalism of the flight crew for the safe landing ofthe plane and the cabin crew and pilots for its safe evacuation.
“We continue to offer our full support to those customers who were onboard the flight.”
Poor maintenance has been blamed for last weeks incident at Heathrow in which a British Airways plane had to make an emergency landing.
Doors that cover engines were not secured causing them to fall off. One punctured a fuel pipe causing a fire.
These are the initial findings of air investigators at Farnborough.
Information from an American safety team that the British Airways plane in last week's Heathrow emergency drama landed with one engine shut down and the other on fire is incorrect, UK accident investigators have said.
Only one of the engines on the BA Airbus A319, which had to turn back to Heathrow with smoke billowing out, was affected, the Air Accidents Investigation Branch (AAIB) said.
The information from the US had come on the website of the US National Transportation Safety Board (NTSB) which is assisting the AAIB on the May 24 incident.
The NTSB information on its website said: "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."
A statement on behalf of the AAIB from the UK's Department for Transport tonight said: "The NTSB reported that the Airbus A319 returned to land with one engine shut down and the other on fire. This information is incorrect: only one of the engines was affected."
With passengers on board and witnesses on the ground seeing smoke coming from the stricken plane, the aircraft landed safely and the 75 passengers and crew were evacuated via emergency chutes. Three people were treated for minor injuries.
The drama closed both runways for a while and although both reopened there were flight cancellations and delays for those heading off for the bank holiday weekend.
Heathrow bosses and the pilot's association Balpa later praised the BA cockpit crew.
NATS air traffic controllers are working with airlines toclear the backlog of flights following runway closures at Heathrow today.
Controllers at Heathrow airport, as well as airports in the South East, are working out which flights are most important to help contain the situation.
Both runways were closed at Heathrow this morningafter a BA flight to Oslo had engine problems and returned to the airport.
We have well-rehearsed plans and processes in place forhandling an incident like this but nevertheless it has been extremely busy forour controllers in Swanwick and at a lot of our airport operations.
Click video. We have footage of the mid-air emergency, taken from inside the aircraft and on the ground.
Heathrow Airport have said that 193 flights have been cancelled following the emergency landing by a BA flight earlier today. They advised all passengers due to travel from the airport today to check the status of their flights with their airline.
- 193 flights have been cancelled
- Delays remain on some flights
- Passengers are advised to check the status of their flights with their airline
British Airways said they are not planning further cancellations. A spokesperson said:
Some flights do remain cancelled but we are not planning further cancellations.
We are still advising passages to check the status of their flight on our website.