Rolls-Royce repeatedly failed to identify a defect that caused one of its engines to explode on a Qantas aircraft carrying more than 400 people over Indonesia three years ago, an Australian safety regulator found.
In its final report on the incident, the Australian Transport Safety Bureau (ATSB) said Rolls-Royce missed multiple opportunities to detect the faulty component which almost certainly would have caused the Airbus A380 to crash had it not been for the exceptional skill of the pilots.
It was the first major safety scare to affect the A380, and led to Qantas suspending its operation of the aircraft for three weeks. The ATSB report could lead to broader requirements for new aircraft certification around the world.
"Those opportunities were missed for a number of reasons, but generally because of ambiguities within the manufacturer's procedures and the non-adherence by a number of the manufacturing staff to those procedures," the report said on Thursday.
The four-engined A380 was flying from Singapore to Sydney with 433 passengers and 26 crew on board when one of its engines exploded, spraying the plane with shrapnel and dropping chunks of debris on Indonesia's Batam island.
A large section of turbine disc crashed into a house, but there were no injuries to anyone either on the plane or on the ground.
The pilots returned to Singapore and landed with limited controls, stopping just 150 meters (490 feet) before the end of the runway with four blown tires, brakes heated to 900 degrees Celsius and fuel leaking to the ground.
Pilot skill likely averted a disaster as the plane suffered a series of systems problems after engine fragments ripped through the wing, puncturing fuel, hydraulic and electronic systems.
After the incident, Rolls-Royce found that a large number of the defective components - the support assemblies manufactured with pipes that feed oil into the engine bearing - did not conform to design specifications. The parts came from a facility in the United Kingdom.
The company's employees missed several opportunities to identify the potential for cracking in the oil feed stub pipes during the production and post-production phase, the ATSB said. As a result, the components were fitted onto a number of the Trent 900 engines and the problem came to light only after the Qantas engine incident.
The ATSB said it issued a recommendation in December 2010 for Rolls-Royce to address the issue, which the company fully complied with. The manufacturer now required specialized checks of the oil and air feed pipes on all Trent 900 engines on A380s, and had made changes to its quality management system.
All defective pipes on other aircraft were either fixed or removed from service.
The Australian aviation safety body said international aircraft certification standards should be updated as the damage to the Qantas plane exceeded parameters currently in use.
"Information from the accident represents an opportunity to incorporate any lessons learned from this accident" in certification processes, it said, adding that its findings had been shared with the European Aviation Safety Agency and the Federal Aviation Administration in the US.
Rolls-Royce said in a statement that it agreed with the ATSB's conclusions and had "applied the lessons learned throughout our engineering, manufacturing and quality assurance procedures to prevent this type of event from happening again".
Colin Smith, the company's director of engineering and technology, added: "This was a serious and rare event which we very much regret."
Qantas said the report "once again underlines the calm, skillful actions of the Qantas crew in returning the aircraft and its passengers safely to Singapore".