Morning Report has received a rarely released cockpit transcript that gives an insight into what happened when one of the engines on an Air New Zealand Dreamliner failed just after takeoff.

Photo: AFP

The transcript details the exchanges between the pilot and air traffic control after the flight from Auckland to Tokyo in December last year was forced to return to Auckland for an urgent landing.

Read the full transcript for ANZ99 on 5 December 2017 here: (PDF, 693KB)

It started out innocuously enough.

"Auckland Tower Air New Zealand 99 good morning ready," said the pilot.

"Air New Zealand 99 Auckland Tower good morning continue to alpha 1," came the respond.

A brief interchange later and that the plane is cleared for immediate takeoff.

Just 10 minutes later there was the first sign of trouble.

"Auckland Air New Zealand 99 we've got an engine failure and we'll just stop here at flight level 150 and will call you back when we've got it sorted."

There's a further gap of nine minutes then the pilot declares that the situation is urgent.

"Auckland approach ANZ99 PAN PAN PAN PAN PAN PAN we have an engine issue on the right engine and we would like to request radar vectors to return to Auckland for landing."

The 'pan-pan' call is made in an event where an aircraft is in difficulty that may escalate, but not yet in a 'mayday' situation.

Then just before 11am - a little less than an hour after takeoff - the plane lands.

Once taxiing the pilot allows himself to relax a little.

The pilot is asked: "Do you wish to taxi straight off to the stand or hold just clear of the runway somewhere?"

"Ah funny you should say that we have been a little busy. Where is 19?"

The problem in December turned out to be with turbine blades which have been wearing out faster than expected. The next day another Boeing 787 on its way to Argentina had a similar problem with its engine and also had to return to the airport.

It's part of a worldwide problem with this type of Rolls-Royce engine - and Air New Zealand has been unlucky to have had two of the most recent problems.

But there's also been another problem with these particular engines.

It relates to a different part of the engine known as the compressor - and it was such a concern that the head of the Civil Aviation Authority, Graeme Harris, wrote to Transport Minister Phil Twyford in April to warn him of a "new and serious engine problem" affecting the Dreamliners.

The CAA told Mr Twyford the regulators in Europe and the US are worried that if compressor blades on one engine fail, then having to load up the other engine with more power to keep flying to the nearest airport, could see that fail as well.

So the regulators have told airlines they have to be only 140 minutes away from an airport. That's meant Air New Zealand has had to change some timetabling and routes and bring in two planes - one from Boeing - and one from an airline called EVA Air - to cover some of the long flights across the Pacific and the increased maintenance checks they need to do.

So far 15 of the engines of the 18 engines that Air New Zealand has of this type, known as Trent 1000 C-package, have had to be sent away for repair. And one Dreamliner of Air New Zealand's 11 is currently out of action because of the maintenance.

Air New Zealand has told RNZ it is following all the directives from regulators and Rolls-Royce and that safety is paramount and non-negotiable.

Rolls-Royce is replacing any worn parts with new parts of the same design and it's working to design and manufacture a replacement part that will not experience the same issue. But no Dreamliners are yet using this new design.

Air New Zealand expects the disruption to schedules to continue until October.