ANZ B789 near Auckland on Dec 6th 2017, engine problem

Last Update: November 11, 2020 / 23:09:30 GMT/Zulu time

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Photo of ANZ Air New Zealand ZK-NZF, Boeing 787-9 Dreamliner — ANZ Air New Zealand ZK-NZF, Boeing 787-9 Dreamliner (Photo credit: masak2_ukon / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Dec 6, 2017

Classification
Incident

Cause
Engine problem

Airline
ANZ Air New Zealand

Flight number
NZ-30

Departure
Auckland, New Zealand

Destination
Buenos Aires, Argentina

Aircraft Registration
ZK-NZF

Aircraft Type
Boeing 787-9 Dreamliner

ICAO Type Designator
B789

An ANZ Air New Zealand Boeing 787-900, registration ZK-NZF performing flight NZ-30 from Auckland (New Zealand) to Buenos Aires,BA (Argentina), was climbing out of Auckland when the crew received abnormal indications for one of the engines (Trent 1000), reduced the engine to idle thrust, stopped the climb at FL180 and decided to return to Auckland. The aircraft dumped fuel and landed safely back in Auckland about 80 minutes after departure.

The airline reported the aircraft needed to return to Auckland due to "engineering requirements". Cancellation and rescheduling of several long haul flights was necessary to undertake such maintenance after Rolls Royce advised some of the Trent 1000 engines require maintenance sooner than previously indicated, no replacement engines are currently available from Rolls Royce.

New Zealand's TAIC reported they opened an investigation into the occurrence described as an engine abnormality.

On May 3rd 2018 the TAIC released a preliminary report also including another similiar occurrence as primary one, see Incident: ANZ B789 near Auckland on Dec 5th 2017, engine shut down in flight.

The TAIC reported: "In both cases an initial borescope inspection found that a turbine blade in the intermediate pressure turbine (IPT) module had fractured and separated from the IPT disc. Features were identified that indicated corrosion fatigue cracking had occurred. In the first occurrence the released blade caused significant damage to the IPT and low-pressure turbine modules. Small pieces of the turbine and stator blades were ejected through the exhaust nozzle and struck the leading edge of the right horizontal stabiliser. Some pieces also chipped the underside of the wing and the side of the fuselage towards the rear, but these did not cause significant damage. The damage in the second occurrence was mainly confined to the IPT module." subsequently stating: "The incidents in December 2017 with engine numbers 10231 and 10227 occurred at 1,545 and 1,453 cycles respectively, up to 12% earlier than the CFL-predicted cycles for the removal of the engines for modification. Therefore the CFL model failed to provide the intended conservative reserve margin before failure."

In April 2018 the FAA and EASA independently released two different Airworthiness Directives, see News: EASA and FAA issue Airworthiness Directives on Boeing 787 engines.

On Nov 12th 2020 New Zealand's TAIC released their final note deciding to close down the investigations into both occurrences stating:

Being satisfied on the facts before it that:

- its inquiries and report published on 3 May 2018 identified the salient safety issues in these occurrences

- the manufacturer has taken safety actions through its programme of blade replacement that have addressed the safety issues

- further lines of inquiry are unlikely to identify any further circumstances that have significant implications for transport safety

- further lines of inquiry are unlikely to allow the Commission to establish any further findings or make further recommendations that may increase transport safety

- further lines of inquiry are unlikely to contribute to the Commission’s purpose of avoiding similar occurrences in the future.

The Commission resolves to now close its inquiries into these two occurrences.