AUCKLAND, NEW ZEALANDAir New Zealand's engineers found that Auckland’s humid climate has caused corrosion in the engines of the airline's Boeing 777-300ER jets.

When Covid-19 hit the global aviation sector in 2020, Air New Zealand sent four 777-300ER along with its eight 777-200ER to desert storage out of the country, where they were less vulnerable to corrosion.

But three 777-300ER aircraft were kept in New Zealand and stored at Auckland International Airport.

Air New Zealand engineering and maintenance group general manager Brett Daley said this was to provide flexibility and operational resilience for the airline when international flying resumed.

Four of the General Electric GE90 engines fitted to the Auckland-based 777-300ER were being repaired overseas after corrosion was found within the low-pressure compressor liner, he said.

“As the Auckland environment can be higher in humidity than desert storage locations, there has been some surface corrosion on four of the GE90 engines,” Daley said.

“These issues do not present a safety concern or impact the structure or integrity of the engine or aircraft.”

He said the planes were placed into storage in accordance with the maintenance procedures supplied via the engine and aircraft manufacturers.

Air New Zealand’s local engineering and maintenance staff managed the aircraft on a regular basis throughout the storage period, he said.

He said the issue was not unique to Air New Zealand.

During the pandemic, the Federal Aviation Administration issued an airworthiness directive requiring airlines to perform pre-flight checks for corrosion on stored aircraft.

The GE90 engine family powers all Boeing 777 models and made its debut in 1995 on a British Airways 777 aircraft. The GE90 series once held the title of the largest, and most powerful, engines in aviation history.

Air New Zealand’s 777-300ERs (four owned, three leased) started entering the airline's fleet in late 2010, five years after it took delivery of its first 777-200ER.

The airline secured purchase rights for both fleets in a 2004 deal.

The four 777-300ERs it bought had a combined list price of $1.4 billion, but airlines usually negotiate discounts.

Air New Zealand has retired its 777-200ER fleet and is looking for buyers of those aircraft. The larger 777-300ER variant will be phased out by 2027 and be replaced by the more fuel-efficient Boeing 787 Dreamliners.

Via Stuff.Co.NZ