Air New Zealand 787-9 Returns to Auckland With Engine Anti-Ice Issue

Air New Zealand flight NZ81, a Boeing 787-9 bound for Hong Kong (HKG), returned to Auckland with an engine anti-ice issue on 4 July.

An Air New Zealand Boeing 787-9 bound for Hong Kong returned to Auckland after experiencing a failed engine anti-ice system on 4 July 2024.

Air New Zealand flight NZ81 was operated by a Boeing 787-9 bound for Hong Kong International Airport (HKG).

The flight crew reported an engine anti-ice system failure during the transit over the Coral Sea.

Air New Zealand NZ81 Auckland-Hong Kong

Flight track of Air New Zealand NZ81 to Hong Kong, showing return to Auckland.

Flight crew reported the engine system failure whilst increasing flight at flight level FL340 (34,000 feet) almost 1000 nautical miles to the north-west of Auckland.

The crew elected to make a precautionary return to Auckland Airport (AKL), and a direct return track was negotiated.

The flight subsequently landed in Auckland without further incident approximately six hours after its initial departure. The technical issue resulted in the cancellation of the Hong Kong service.

Aircraft Details

An Air New Zealand Boeing 787-9 approaches to land.

The aircraft conducting the NZ81 service to Hong Kong was a Boeing 787-9 Dreamliner, registered ZK-NZI.

This is an eight year old Trent engine equipped wide-body aircraft belonging to the national carrier Air New Zealand.

It has been in operational service with the airline since its initial delivery in July 2016.

Engine Anti-Ice System

Rolls-Royce Trent engines, like many modern jet engines, use a bleed air system for anti-icing.

This system taps hot air from the engine compressor stages and directs it through passages within critical components like the engine inlet (core inlet) and the Engine Section Stator (ESS).

Here’s how it works:

Bleed air extraction: Compressed air, which is hot due to the compression process, is bled from the high-pressure stages of the engine compressor.
Heating critical components: This hot bleed air is then routed through passages within the engine inlet and ESS. The hot air warms these surfaces, preventing ice accumulation on them during flight in freezing and humid conditions.
Maintaining engine performance: By keeping these critical components free of ice, the bleed air anti-ice system helps ensure smooth airflow into the engine, which is vital for maintaining engine performance and efficiency.