Airways will trial a satellite system that continually tracks planes across vast ocean areas, cutting the risk of an aircraft vanishing as Malaysian Airlines flight MH370 did nearly three years ago.

The new system will give air traffic controllers another layer of surveillance but it doesn't guarantee against the possibility of someone aboard the plane disabling equipment to prevent tracking.

Airways is working with United States firm Aireon which has launched 10 of a constellation of 66 satellites in near space which will start sending test data back to the New Zealand air traffic controller from June.

Airways' chief operating officer Pauline Lamb said the state-owned enterprise would examine what the data from the Automatic Dependent Surveillance-Broadcast (ADS-B) system meant for airline customers and their passengers.


"Instead of having data and surveillance from hilltop sites you've got satellites going around the world and feeding information from the top down which gives us a good picture of where aircraft are," she said.

"At the moment we've got a really good picture of domestic traffic and in and out of local airports but we're trying to fine-tune the arrival times of international traffic and avoid congestion at Auckland especially with that growth."

The technology would have safety benefits too.

Three years ago next week MH370 with 239 people aboard went missing on a flight from Kuala Lumpur to Beijing. One theory is that its transmitting equipment was deliberately disabled and the plane changed course and crashed in the Southern Indian Ocean after controllers lost contact with it.

Lamb said in Airways' 30 million square kilometres of airspace there were already layers of tracking that minimises such an occurrence. Aircraft communicate with controllers on the ground and their airline through a datalink system or voice calls every eight minutes (nearly half the international minimum interval).

Controllers also knew where the aircraft was meant to be through plotting and when the next communication was due.

"We've got massive amounts of alerts and bits and pieces if that doesn't happen," said Lamb.

"You can never say never but the amount of systems we have in place puts us in quite a different place to MH370."

But even the ADSB transponder could be turned off and those on the ground potentially oblivious, she said.

Aireon expects to have all its satellites launched - via Elon Musk's Space X rockets - by the first quarter of next year, providing total coverage of the globe. It will receive signals every one to eight seconds from all equipped planes.

Most planes are equipped with the transmitting technology.

Lamb said Airways should have a clear picture of the use of the system within 18 months of the trial starting.