Jetstar B788 near Guam on Aug 6th 2016, engine shut down in flight

Last Update: January 3, 2017 / 13:53:45 GMT/Zulu time

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Photo of Jetstar Airways VH-VKK, Boeing 787-8 Dreamliner — Jetstar Airways VH-VKK, Boeing 787-8 Dreamliner (Photo credit: Jetstar Airways / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Aug 6, 2016

Classification
Incident

Cause
Engine shut down in flight

Airline
Jetstar Airways

Flight number
JQ-12

Departure
Tokyo Narita, Japan

Destination
Coolangatta Gold Coast, Australia

Aircraft Registration
VH-VKK

Aircraft Type
Boeing 787-8 Dreamliner

ICAO Type Designator
B788

A Jetstar Boeing 787-800, registration VH-VKK performing flight JQ-12 from Tokyo Narita (Japan) to Coolangatta Gold Coast,QL (Australia) with 309 passengers and 11 crew, was enroute at FL400 over the Pacific Ocean about 250nm north of Guam (Guam) when the crew received a low oil pressure indication for the right hand engine (GEnx) and shut the engine down. The aircraft diverted to Guam for a safe landing about 70 minutes later.

The airline reported an oil pressure warning indication prompted the crew to shut the engine down and divert to Guam.

A replacement Boeing 787-800 registration VH-VKF was dispatched to Guam, is estimated to depart Guam shortly and reach Coolangatta with a delay of 26.5 hours.

On Aug 12th 2016 Australia's TSB (ATSB) reported they have opened an investigation into the occurrence rated an incident. The right hand engine was shut down after the crew received low oil quantity and low oil pressure indications.

The ATSB released their final report releasing following safety message:

This incident highlights the importance of flight crew complying with checklist actions when dealing with a fault condition. Inflight, the crew did not have knowledge of the extent of the damage to the engine TGB (Transfer Gear Box). However, by following their training and checklist procedures, they reduced the risk of a potential escalation of the fault.

The ATSB reported the crew received a "ELEC GEN DRIVE R2", worked the related checklist which disconnected the generator from the right hand engine's accessory gear box (AGB) and starting the APU to have the APU's generator online.

About 30 minutes later the crew noticed a low oil pressure indication for the right hand engine, worked the related checklists, disconnected autothrust for the right hand engine and brough the thrust lever to idle, which briefly cleared the fault, however, when the fault returned the crew proceeded in the checklist and shut the engine down. The crew identified Guam as their nearest airport, declared PAN, descended to FL220 and diverted to Guam for a safe landing without further incident.

An initial maintenance inspection revealed oil throughout the engine and a considerable amount of metallic debris within the engine oil system. The operator decided to replace the engine as the most expeditious option available.

The engine manufacturer determined that 7 chips had already reached the magnetic chip detector of the right hand oil system, when the crew received the generator fault message. A chip detector message was generated when an 8th chip was detected, in the following 4 minutes 3 more chips were detected, a rapid loss of engine oil occurred and there was a momentary spike in engine vibrations from the #1 bearing followed by the low oil pressure indication. The engine was shut down and the aircraft landed 52 minutes later.

An inspection revealed the transfer gear box, which connects the AGB to the Inlet Gear Box (IGB)/engine, had a fractured housing, its oil screen was filled with metallic debris, the failure was consistent with the scenario described and addressed in Service Bulletin SB 72-0298.

The operator immediately adopted the service bulletin and according to the SB identified engines with the highest risks and lowest risks. The occurrence engine had been identified as the one with the lowest risk within the operator's fleet and thus was scheduled to be modified by Dec 31st 2016.

The ATSB commented: "The ATSB notes that the failure of the TGB and loss of oil is a potential failure mode known to the engine manufacturer and operator. This condition is under risk management through the service bulletin process and the operator was within the compliance period at the time of the incident. Prior to the incident flight, the incident TGB was assessed as being in the lowest risk profile for the operator’s fleet."

The ATSB wrote: "All machinery have a natural frequency of vibration. If a particular abnormality in the machinery generates a forced vibration, which vibrates in-phase and at the same frequency as the natural frequency of vibration, then the energy will magnify. The frequency at which this occurs is known as the resonant frequency (Figure 4). If there is insufficient damping present at the resonant frequency, then the amplitude of the vibrations will increase with each cycle. Excessive movement of components with high energy can cause a catastrophic failure of the machinery."