LONDON (AP) - A British Airways (BA) jet that made an emergency landing at Heathrow Airport last week lost panels from both its engines after they were left unlatched during maintenance, accident investigators said on Friday.
In an initial report on the incident, the Air Accidents Investigation Branch said the unlatched fan cowl doors were not noticed before the Airbus A319-131 took off.
The covers detached as the plane climbed, damaging the airframe and some aircraft systems and rupturing a fuel pipe on the plane's right engine, which developed an external fire. The pilots managed to land the plane on one engine.
Britain's Transport Secretary Patrick McLoughlin said the report contained "serious findings" and called on the industry to act to ensure safety.
"Airline passengers have the right to expect to travel safely and it is the responsibility of all involved in aviation to make sure that happens," he said.
Britain's busiest airport was briefly closed on May 24 after the Oslo-bound flight made the emergency landing.
TV footage showed smoke streaming from one of the engines. The 80 passengers and crew were evacuated without serious injuries, and fire crews quickly put out the blaze.
The report said that in 2012, Airbus reported 32 cases in which fan cowl doors became detached, usually during take-off, but none of the incidents up to that point had caused an engine fire.
Investigators said the BA incident "has shown that the consequences of fan cowl door detachment are unpredictable and can present a greater risk to flight safety than previously experienced". The report recommended Airbus stress to airlines the importance of ensuring doors are latched before take-off.
BA said it had already acted to implement the recommendation.
It said it could not comment further on the incident while the investigation continued.
"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," said BA chief executive Keith Williams.
"We continue to offer our full support to those customers who were onboard the flight."