China Airlines A333 near Cairns on Oct 3rd 2013, engine shut down in flight

Last Update: December 10, 2015 / 14:29:49 GMT/Zulu time

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Photo of China Airlines B-18358, Airbus A330-300 — China Airlines B-18358, Airbus A330-300 (Photo credit: ZK-NGJ / Flickr / License: CC by-nd)

Incident Facts

Date of incident
Oct 3, 2013

Classification
Incident

Cause
Engine shut down in flight

Airline
China Airlines

Flight number
CI-52

Departure
Sydney, Australia

Destination
Taipei, Taiwan

Aircraft Registration
B-18358

Aircraft Type
Airbus A330-300

ICAO Type Designator
A333

A China Airlines Airbus A330-300, registration B-18358 performing flight CI-52 from Sydney,NS (Australia) to Taipei (Taiwan) with 205 passengers and 13 crew, was enroute at FL360 near Cape York (most northern point of Australia) when the crew reported they were on single engine (CF6) due to zero oil pressure on the left hand engine, no fire, and needed a tow upon arrival. The aircraft diverted to Cairns,QL, about 420nm south of Cape York, and landed safely on runway 15 about 90 minutes later. The aircraft was able to vacate the runway and taxied half way to the apron, but was then instructed to hold position and shut down to be towed to the gate.

On Oct 8th 2013 the Australian Transportation Safety Board ATSB reported an investigation into the occurrence rated an incident was opened. The crew observed a low engine oil quantity and low engine oil pressure indication for the left hand engine, shut the engine down and diverted to Cairns.

On Dec 10th 2015 the ATSB released their final report concluding the probable causes of the incident were:

Contributing factors

- The number one engine air turbine starter experienced an in-flight failure of the over-running output section as a result failure of the output shaft bearing.

- Debris originating from the starter failure was not contained by the starter casing and severed the number one engine B-sump oil scavenge pipe. (Safety issue)

- Complete loss of engine oil through the severed oil scavenge pipe resulted in a forcedshutdown of the number one engine.

Other factors that increase risk

- The starter was operated for a period of time with a marginal oil level which may have affected the longevity of the output shaft bearing.

The ATSB reported that the crew received a low oil quantity indication for the left hand engine about 4 hours into the flight, a minute later a low oil pressure indication for the left hand engine followed. The crew shut the engine down and diverted to Cairns for a safe landing two hours later.

A preliminary inspection by maintenance revealed that the starter unit had suffered an uncontained failure. Debris released by the starter unit severed the B oil scavenge pipe and damaged, without causing a leak there, the C oil scavenge pipe. As result all engine oil was lost from the #1 engine necessitating the shut down of the engine.

The ATSB analysed:

The most likely failure sequence of air turbine starter (part number 3505468-6, serial number GRTF6248) was a failure of the output shaft bearing, followed by the hub gear, pawls and ratchets and then finally failure of the housing. The starter manufacturer determined that the most probable cause was excessive loading, which could have been associated with a previous crash engagement or a transient load provided by the horizontal driveshaft. While direct evidence of a crash engagement was not detected on the previous 20 starts, the starter manufacturer indicated that it did not necessarily mean the output shaft had not been damaged prior to this time and that it may have taken operation over an extended period to manifest in a failure. The starter manufacturer demonstrated that the impact load and subsequent damage to the shaft was a function of velocity and acceleration at engagement and the backlash in the start system at the moment of engagement. The engine manufacturer also performed some analysis which showed that a high transient load applied to the bearing could lead to overrunning bearing failure. The risk analysis conducted by the starter manufacturer, covering the period from January 2007 to August 2014, identified 13 bearing failures in the starter type. The overall risk to the fleet was determined to be at the acceptable level.

At the most recent oil change, the quantity of oil drained was just above that required for a replacement starter to be installed. While a lack of lubrication did not appear to be an issue in this case, the high loss of oil between maintenance leading up to the failure was potentially indicative of a leak. This allowed the oil level to get down to around the lower limit of 600 mL, where previously the oil had shown little loss between inspections. The engine manufacturer indicated that output shaft seal leaking was responsible for a high number of starter shop findings. The design of the output shaft seal assembly meant that it was installation-sensitive and steps have been taken by both the engine and starter manufacturers to clarify and provide additional information to operators and maintainers of the affected starters.