Narrative:An Airbus A380-842 passenger jet, registered VH-OQA, incurred substantial damage in an accident near Batam Island, Indonesia. There were no fatalities. The airplane operated on Qantas flight QF32 from Singapore-Changi International Airport (SIN) to Sydney-Kingsford Smith International Airport, NSW (SYD).
The airplane took off from runway 20C at 09.56. Following a normal takeoff, the crew retracted the landing gear and flaps. The crew reported that, while
maintaining 250 kts in the climb and passing 7,000 ft above mean sea level, they heard two almost coincident 'loud bangs', followed shortly after by indications of a failure of the No 2 engine.
The aircraft levelled off and because of an overheat warning of engine No 2, thrust for this engine was moved to 'idle'. Meanwhile, at 10:02, when the airplane was flying over Batam Landmass, the crew radioed a PAN call to the Approach Controller citing a possible engine failure. At that time, the pilot of QFA 32 maintained height on 7,500 feet and requested to be on heading 150 degrees to investigate the problem, but did not request to return to Singapore immediately. Later on at 10.21, the crew reported that they had been gone through an extensive checklist and found that there was a hole in the side of engine number 2 and it had damaged a part of the wing. The pilot then requested to hold for half an hour before making an approach to Changi Airport.
A moment later, an air traffic controller from Batam Tower, who had received a report stating that parts of an aircraft had been found on Batam Center-Batam Island made a report to Singapore ATC Approach Sector about the finding.
The pilot informed Singapore ATC that other engines apart from engine number 2 appeared to be functioning normal; thus required an approach on Runway 20C at Changi Airport and a towing assistance when the aircraft stopped at the end of the runway.
While the aircraft was stopping abeam taxiway E10, Changi’s Airport Emergency Service (AES) found that engine number 2 was damaged near the rear of the engine and fuel had leaked from the port side (left wing). Moreover, there was smoke from tyre number 7 and there were 4 tyres deflated, meanwhile, the pilot was not able to shut off engine number 1. Nevertheless, it was safe to disembark passengers. Exactly at 13:54, all passengers had been disembarked, and finally at 14:53, engine number 1 was finally able to be shutdown.
Analysis of the preliminary elements from the incident investigation shows that an oil fire in the HP/IP structure cavity may have caused the failure of the Intermediate Pressure Turbine (IPT) Disc.
CONTRIBUTING SAFETY FACTORS:
1. Disc failure during the occurrence flight
- Over time, a fatigue crack had developed in the thin-wall section of the oil feed stub pipe in the No. 2 engine to the extent that, during the occurrence flight, opening of the crack through normal movement within the engine released oil into the HP/IP buffer space.
- Auto-ignition of the oil leaking from the oil feed stub pipe created an intense and sustained fire within the HP/IP buffer space that resulted in localised heat damage to the intermediate pressure (IP) turbine disc.
- The IP turbine disc separated from the drive arm and accelerated.
- Following the separation of the IP turbine disc from the drive arm, the engine behaved in a manner that differed from the engine manufacturer’s modelling and experience with other engines in the Trent family, with the result that the IP turbine disc accelerated to a rotational speed in excess of its design capacity whereupon it burst in a hazardous manner. [Safety issue]
2. Manufacture and release into service of engine serial number 91045
- During the manufacture of the HP/IP bearing support assembly fitted to the No. 2 engine (serial number 91045), movement of the hub during the machining processes resulted in a critically reduced wall thickness within the counter bore region of the oil feed stub pipe.
- It was probable that a non-conformance in the location of the oil feed stub pipe interference bore was reported by the coordinate measuring machine during the manufacturing process, but that the non-conformance was either not detected or not declared by inspection personnel, resulting in the assembly being released into service with a reduced wall thickness in the oil feed stub pipe.
3. Opportunity to manage the non-conforming oil feed stub pipes in the Trent 900 fleet
- The statistical analysis used to estimate maximum likely oil feed stub pipe counter bore misalignment, and resulting thin wall section, did not adequately represent the population of actual misalignments in engines already released into service, nor did it implicitly provide a level of uncertainty in the results.
- The language used to define the size of the non-conformance on the retrospective concession form did not effectively communicate the uncertainty of the statistical analysis to those assessing and approving the concession.
- The engine manufacturer did not have a requirement for an expert review of statistical analyses used in retrospective concession applications. [Safety issue]
- The engine manufacturer's process for retrospective concessions did not specify when in the process the Chief Engineer and Business Quality Director approvals were to be obtained. Having them as the final approval in the process resulted in an increased probability that the fleet-wide risk assessment would not occur. [Safety issue]
- The retrospective concession was not approved by the Chief Engineer and Business Quality Director, as required by the group quality procedures relating to retrospective concessions, denying them the opportunity to assess the risk to the in-service fleet.
Uncontained engine failure
Forced landing on runway
» Ministry of Transport, Indonesia
Follow-up / safety actions
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Singapore-Changi International Airport to Sydney-Kingsford Smith International Airport, NSW as the crow flies is 6263 km (3914 miles).