Doors on both engines of the British Airways plane that was involved in an emergency landing at Heathrow Airport last week had been left unlatched during maintenance, according to an official accident report.

Flight BA762 was on its way to Oslo from the airport last Friday when it was forced to return to London shortly after take off.

Smoke was seen pouring from one of the engines and the plane appeared damaged as it flew over southeast, central and west London. The unlatching had not been noticed before the Airbus A319 took off, according to the Air Accidents Investigation Branch (AAIB) report.

The fan cowl doors from both engines detached as the aircraft left the runway at Heathrow, puncturing a fuel pipe on the right engine, the report said.

The report said "Subsequent investigation revealed that the fan cowl doors on both engines were left unlatched during maintenance and this was not identified prior to aircraft departure."

Aircraft systems punctured

The detaching also punctured the airframe and some aircraft systems and the flight crew, led by the 50-year-old captain, decided to return to Heathrow. On the approach to land an external fire developed on the right engine, with the left engine continuing to perform normally throughout the flight.

The report added that the right engine was shut down and the aircraft landed safely. The emergency services quickly attended and extinguished the fire in the right engine.

The 75 passengers and 5 crew were evacuated via emergency chutes, while 3 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.

In response to the report, British Airways chief executive Keith Williams said "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 of the 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" he added.