Air New Zealand passengers face more disruption as Dreamliners hit by further Rolls-Royce engine problems

Air New Zealand international passengers face more disruption from problems with some of the Rolls-Royce engines on its Dreamliners.

Airlines operating some of the engines have been ordered by global safety regulators to carry out more regular checks on them, meaning they will be grounded much more frequently for maintenance.

This comes on top of turbine blade problems two Air New Zealand planes suffered late last year.

Rolls-Royce, in conjunction with European regulator EASA, has issued a directive requiring operators of a type of Trent 1000 engine known as 'Package C' to carry out earlier than usual maintenance checks on a specific part of the engine compressor.

The airline has not yet released details of schedule changes but this morning said there would be disruption.

"Air New Zealand expects there will be some impact to its international schedule as a result of the checks and thanks customers in advance for their patience as it works through this challenge at what is a very busy time for travel."

It said the check was already required prior to the engine reaching a flying threshold of 2000 cycles or one way journeys but the directive reduces that timeframe to 300 cycles.

Rolls-Royce said 380 engines globally are affected by the directive, including nine in the Air New Zealand 787 fleet.

A spokesperson for Air New Zealand told the Herald that the "directive focuses on the Intermediate Pressure Compressor where Rolls-Royce has seen issues with the durability of the part."

"The check involves looking at an area of the compressor, it is completed on wing (without removing the engine) and only takes a couple of hours."

Trent 1000 Package C engines that have operated fewer than 300 cycles are unaffected by this directive.

Air New Zealand also has Trent 1000 TEN model engines in its 787 fleet and these are unaffected.

But there could be worse to come for operators of the affected engines.

Bloomberg reports the United States Federal Aviation Administration is about to order that aircraft fitted with Package C engines have the flight time over water and remote areas slashed.

The so-called ETOPs changes could force some airlines to modify their flightpaths and this would hit long range carriers over the Pacific, such as Air New Zealand if it does not have the improved engines on aircraft flying to north and South America.

Extended-range Twin-engine Operational Performance Standards, a rule which permits twin engine aircraft to fly routes which, at some point, are more than 60 minutes flying time away from the nearest airport if they have to divert.

It is now set at 330 minutes for Dreamliners but according to Bloomberg this could be cut to 140 minutes by the FAA early next week.

Air New Zealand experienced turbine blade problems in planes on successive days last December and this led to accelerated repairs in Singapore for the engines and disruption to tens of thousands of passengers.

Air New Zealand was forced to use Portuguese charter operator Hi Fly on transtasman routes over summer.