Multiple probes into NZ plane radar fault
A third investigation has been launched into a nationwide air traffic control fault that left about 50 planes flying blind and halted departures across New Zealand.
The aircraft were airborne when an unexplained glitch knocked out air traffic control radar on Tuesday, forcing them land without its help and grounding those ready to take off.
The Transport Accident Investigation Commission said on Wednesday it would be joining the Airways Corporation and Civil Aviation Authority in investigating the fault.
An apologetic Airways New Zealand, responsible for air traffic control, is blaming an "internal network outage" for disrupting its communication and surveillance systems.
The outage hit at 2.41pm (1241 AEST) on Tuesday and the radar system wasn't fully operational until 4.30pm.
State-owned Airways said none of the aircraft were in danger.
The Airline Pilots' Association said it didn't yet know what caused the fault but it was obviously concerning.
However, spokeswoman Lisa Williams said air traffic controllers should be commended for helping pilots land the planes.
"Air traffic controllers train for events like this, and today put them to the test but they did brilliantly."
Pilots in the air would have followed the rules about what to do in such an "extremely rare" situation, she said.
"They kick into pilot mode to ensure they are getting their plane on the ground safely and their passengers happy and safe."
Air New Zealand said the problem affected about 160 domestic and international flights.
Airways NZ's Radar Centre is based in Christchurch with radar equipment located around the country.
In a statement, spokeswoman Emily Davies said it has back-up processes to safely deal with network failures.
"Airways quickly worked to resolve the issue and has thoroughly tested the integrity of the system," she said.
It was completely confident in the safety of all its systems when it resumed departures, she said.
