Air New Zealand’s on-time performance of its domestic jets has slipped in the last three months, with almost a quarter of flights classified as arriving late.

From 88 per cent of flights arriving within 15 minutes of their scheduled times in January, this had fallen to 77 per cent in March - behind rival Jetstar and at a time when Air New Zealand was gearing up to put up prices.

For the last 12 months, domestic jet on-time performance (OTP) slipped from 85.6 per cent to 77 per cent as the airline grapples with problems with Pratt & Whitney engines for its A320/21 fleet.

Air NZ has said up to five A321s could be on the ground at any one time because of the P&W problem. Turbo prop ATRs are doing more flying on the 2800 domestic services the airline flies a week.

Jetstar, with 230 departures a week, has a much smaller domestic network in this country than Air NZ. The Australian airline is reporting March was one of the best months in recent years, with not a single flight cancelled and 78.6 per cent of flights arriving within 15 minutes of their scheduled time.

So far this month, Jetstar’s OTP in this country is around 80 per cent and the cancellation rate at around 1.3 per cent.

Air NZ’s regional aircraft reliability has also fallen in the past 12 months from 87 per cent in April 2023 to 78 per cent in March this year.

The airline’s overall OTP is slipping for the 108 aircraft in its fleet. Across all flights, it fell from 84.2 per cent in April last year to 77.2 per cent.

International short-haul services - which use Airbus aircraft affected by the engine problem - have seen OTP slide from 72.7 per cent to 68 per cent.

However, international long haul flights are doing better with OTP performance improving from 68.5 per cent to 77.2 per cent in the latest 12 months.

The figures disclosed on the airline’s website showed the worst month for Air NZ was last December, a peak travel month where the entire aviation system comes under strain. Total airline OTP fell to 72.6 per cent that month.

Air New Zealand says a three-month comparison shows improvement over its network. In January to March this year, OTP was 78.7 per cent, a 2.4 percentage point increase compared to the same period last year.

Chief operating officer Alex Marren said the airline knew being on time was important to its customers.

“We strive for that with each and every flight.”

“There’s still plenty of room to improve and we’re always looking at how we can add more resilience to our network to ensure our services consistently arrive on schedule, including how we turn aircraft for the next service or how we can more quickly recover from a weather event,” she said.

"Our goal is to increase our on-time performance to more than 83 per cent, and our ambition is to be the most reliable airline in the region and among the top in the world. However, the continued impacts of engine availability mean we simply don’t have all the aircraft flying that we’d like."

While the engine availability constraints have presented hurdles, making decisions like pausing the Chicago route until the middle of next year gave it greater operational surety and resilience.

Jetstar says its performance in March followed nearly 12 months of continued operational improvement, which it attributes to a range of initiatives. It has hired more than 120 front-line staff since the beginning of 2023 and rostered more crew on standby.

It also has more spare parts available to fix engineering issues and additional aircraft on standby during peak travel periods such as the Easter holidays, and technology investments include updating the Jetstar app.

The airline is increasing services here, with its New Zealand domestic network scheduled to reach up to 100 per cent of pre-Covid levels from mid-year, and its transtasman network operating almost 40 per cent higher than in 2019.

Jetstar planes have IAE V2500 engines that aren’t affected by the same issue.

In Jetstar’s home market, Australia, airline punctuality and reliability is monitored by the Bureau of Infrastructure and Transport Research Economics.

Bonza, Hinterland, Jetstar, Qantas, QantasLink, Rex Airlines, Skytrans, Virgin Australia and Virgin Australia Regional Airlines report to the government agency.

Jetstar’s OTP (for arrivals) was 80.9 per cent for March, ahead of parent airline Qantas, Rex, Skytrans, and Virgin and the overall average of 77.2 per cent.

Grant Bradley has been working at the Herald since 1993. He is the Business Herald’s deputy editor and covers aviation and tourism.

This article was originally posted on the NZ Herald here.