In-flight uncontained engine failure Airbus A380-842, VH-OQA, overhead Batam Island, Indonesia, on 4 November 2010

AO-2010-089

Final report

Report release date: 27/06/2013

What happened

On 4 November 2010, while climbing through 7,000 ft after departing from Changi Airport, Singapore, the Airbus A380 registered VH-OQA, sustained an uncontained engine rotor failure (UERF) of the No. 2 engine, a Rolls-Royce Trent 900. Debris from the UERF impacted the aircraft, resulting in significant structural and systems damage.

The flight crew managed the situation and, after completing the required actions for the multitude of system failures, safely returned to and landed at Changi Airport.

What the ATSB found

The Australian Transport Safety Bureau (ATSB) found that a number of oil feed stub pipes within the High Pressure / Intermediate pressure (HP/IP) hub assembly were manufactured with thin wall sections that did not conform to the design specifications. These non-conforming pipes were fitted to Trent 900 engines, including the No. 2 engine on VH-OQA. The thin wall section significantly reduced the life of the oil feed stub pipe on the No. 2 engine so that a fatigue crack developed, ultimately releasing oil during the flight that resulted in an internal oil fire. That fire led to the separation of the intermediate pressure turbine disc from the drive shaft. The disc accelerated and burst with sufficient force that the engine structure could not contain it, releasing high-energy debris.

What has been done to fix it

Following the UERF, the ATSB, Rolls-Royce plc, regulatory authorities and operators of A380 aircraft with Trent 900 engines took a range of steps to ensure that HP/IP hub assemblies with non-conforming oil feed stub pipes were identified and either removed from service, or managed to ensure their safe continued operation. Rolls-Royce also released an engine control software update that included an IP turbine overspeed protection system (IPTOS) that is designed to shut the engine down before the turbine disc can overspeed, in the unlikely event that a similar failure occurs.

Rolls-Royce has also made a range of changes to their quality management system to improve the way in which they manage non-conforming parts, both during the manufacturing process and when it has been identified that parts had unknowingly been released into service with non-conformances.

Safety message

The ATSB identified a number of issues during the manufacture of Trent 900 HP/IP hub assemblies that resulted in their release into service with non-conforming oil feed stub pipes. Those issues highlighted the importance of providing clear procedures during the manufacturing process and of personnel complying with those procedures. Even though modern civil turbine engines are very reliable, and UERFs are very rare events, the resulting damage from such a failure can be significant and the potential effects catastrophic. This accident represents an opportunity for the regulatory authorities to incorporate any lessons learned into their certification advisory material to enhance the safety of future aircraft designs.

Interim report

Report release date: 18/05/2011

This interim report details factual information established in the investigation’s evidence collection phase and has been prepared to provide timely information to the industry and public. Interim reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this interim report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

The Australian Transport Safety Bureau is investigating an occurrence involving a Qantas A380 aircraft that experienced an uncontained engine failure over Batam Island, Indonesia on 4 November 2010. The aircraft landed safely in Singapore having returned with the aircraft's No 2 engine shut down. There were no injuries.

The investigation team has inspected the damaged engine and components and determined the sequence of events that led to the failure of the engine disc.

The investigation is also examining the airframe and systems damage that resulted from the engine disc burst to understand its effect on those systems and the impact on flight safety. That includes their effect on the aircraft's handling and performance and on crew workload. A flight simulator program was used to conduct a number of tests in a certified A380 flight simulator. Analysis of the flight simulation test data is ongoing.

Preliminary report

Report release date: 03/12/2010

This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

On 4 November 2010, at 0157 Universal Coordinated Time (UTC), an Airbus A380 aircraft, registered VH-OQA (OQA), being operated as Qantas flight 32, departed from runway 20 centre (20C) at Changi Airport, Singapore for Sydney, New South Wales. On board the aircraft were five flight crew, 24 cabin crew and 440 passengers (a total of 469 persons on board).

Following a normal take-off, 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 crew advised Singapore Air Traffic Control of the situation and were provided with radar vectors to a holding pattern. The crew undertook a series of actions before returning the aircraft to land at Singapore. There were no reported injuries to the crew or passengers on the aircraft. There were reports of minor injuries to two persons on Batam Island, Indonesia.

A subsequent examination of the aircraft indicated that the No 2 engine had sustained an uncontained failure of the Intermediate Pressure (IP) turbine disc. Sections of the liberated disc penetrated the left wing and the left wing-to-fuselage fairing, resulting in structural and systems damage to the aircraft.

As a result of this occurrence, a number of safety actions were immediately undertaken by Qantas, Airbus, Rolls-Royce plc and the European Aviation Safety Agency. On 1 December 2010, the ATSB issued a safety recommendation to Rolls-Royce plc in respect of the Trent 900 series engine high pressure/intermediate pressure bearing structure oil feed stub pipes. In addition, the Civil Aviation Safety Authority issued a Regulation 38 maintenance direction that addressed the immediate safety of flight concerns in respect of Qantas A380 operations with the Trent 900 series engine. On 2 December 2010, Qantas advised that the requirements of Rolls-Royce plc Service Bulletin RB211-72-G595 would take place within the next 24 hours on engines in place on A380 aircraft currently in service, and before further flight on engines on aircraft not yet returned to service.

Recommendations

Initial recommendation for misaligned stub pipe counter-boring that led to reduced wall thickness

Safety Issue

Misaligned stub pipe counter-boring is understood to be related to the manufacturing process. This condition could lead to an elevated risk of fatigue crack initiation and growth, oil leakage and potential catastrophic engine failure from a resulting oil fire.

As a result of the identified critical safety issue, the Australian Transport Safety Bureau issues the following safety recommendation:

Safety Recommendation AO-2010-089-SR-012

The Australian Transport Safety Bureau recommends that Rolls-Royce plc address the safety issue and take actions necessary to ensure the safety of flight operations in transport aircraft equipped with Rolls-Royce plc Trent 900 series engines.

Airframe certification standards in the case of an uncontained engine rotor failure - EASA

Safety Issue

The evolution of the current advisory material relating to the minimisation of hazards resulting from uncontained engine rotor failures was based on service experience, including accident investigation findings. The damage to Airbus A380-842 VH-OQA exceeded the modelling used in the UERF safety analysis and, therefore, represents an opportunity to incorporate any lessons learned from this accident into the advisory material.

ATSB safety recommendation AO-2010-089-SR-039

The Australian Transport Safety Bureau recommends that the European Aviation Safety Agency, in cooperation with the US Federal Aviation Administration, review the damage sustained by Airbus A380-842, VH-OQA following the uncontained engine rotor failure overhead Batam Island, Indonesia, to incorporate any lessons learned from this accident into the advisory material.

Airframe certification standards in the case of an uncontained engine rotor failure - US FAA

Safety Issue

The evolution of the current advisory material relating to the minimisation of hazards resulting from uncontained engine rotor failures was based on service experience, including accident investigation findings. The damage to Airbus A380-842 VH-OQA exceeded the modelling used in the UERF safety analysis and, therefore, represents an opportunity to incorporate any lessons learned from this accident into the advisory material.

ATSB safety recommendation AO-2010-089-SR-040

The Australian Transport Safety Bureau recommends that the US Federal Aviation Administration, in cooperation with the European Aviation Safety Agency, review the damage sustained by Airbus A380-842, VH-OQA following the uncontained engine rotor failure overhead Batam Island, Indonesia, to incorporate any lessons learned from this accident into the advisory material.

Occurrence summary

Investigation number AO-2010-089
Occurrence date 04/11/2010
Location overhead Batam Island, Indonesia
State International
Report release date 27/06/2013
Report status Final
Investigation level Systemic
Investigation type Occurrence Investigation
Investigation status Completed
Mode of transport Aviation
Aviation occurrence category Engine failure or malfunction
Occurrence class Accident
Highest injury level None

Aircraft details

Manufacturer Airbus
Model A380
Registration VH-OQA
Serial number 14
Aircraft operator Qantas Airways
Sector Jet
Operation type Air Transport High Capacity
Departure point Singapore
Destination Sydney, NSW
Damage Substantial