Flight radar failure to be investigated by Civil Aviation Authority

The Airways Corporation radar dome at Hawkins Hill in Wellington.
ANTHONY PHELPS / FAIRFAX NZ
The Airways Corporation radar dome at Hawkins Hill in Wellington.

The Civil Aviation Authority (CAA) has launched an investigation into a radar outage that grounded hundreds of flights across the country.

At 2:41pm on Tuesday, an "internal network failure" affected the national radar system, causing all flights to be grounded until about 4pm.

In a statement, a CAA spokesman said the organisation would launch a safety investigation focused on the cause or causes of the outage as well as looking for solutions to prevent it happening again.

"At no point were any passengers or aircraft at risk, due to the immediate implementation of Airways contingency planning procedures," the spokesman said.

CAA said the grounding of flights was part of Airway's "contingency planning procedures", allowing all flights to land using "visual manual separation".

"The system was thoroughly tested and fully stable by 3.30pm.

"Flights returned to partial operation by 4pm and then were fully operational at 4:30 pm. Flights were resumed on a priority basis with major trunk routes and jet flights being resumed first."

The radar system acts as a "highway in the sky".
Airways
The radar system acts as a "highway in the sky".

'VERY UNUSUAL'

Massey University School of Aviation chief executive officer Ashok Poduval said procedural separation involved aircraft navigating using ground-based equipment.

As aircraft came into the airport, they were spaced a certain number of minutes behind each other, he said.

"They've probably grounded all the departing flights because without radar, the whole efficiency goes down. It basically slows everything down."

Nationwide radar breakdowns were uncommon, he said.

"In the last 10 years I haven't heard of any real radar breakdown of this magnitude in New Zealand. It's not common at all, it's something very unusual."

HOW THE SYSTEM WORKS

Airways New Zealand controls all air movements within New Zealand's 30 million square kilometres of air space, managing the country's two radar centres, airports and military bases.

It is responsible for preventing aircraft collisions in the air and on the ground through its air navigation and communications systems.

New Zealand's national air traffic control system is called SkyLine. This system takes radar and other tracking data, merges it into a single aircraft target, correlates it with flight data sent from airlines, and displays it to air traffic controllers.

Aviation New Zealand chief executive Samantha Sharif said it was useful to think of air traffic as an inverted wedding cake.

"You have different tiers of control. You have aerodrome control, which is in the vicinity of an airport. Then above that, you have area control, then en route control, and then terminal control.

"As you go higher, the expanses that are covered tend to be broader. At the aerodrome, it's done through people looking out at what's happening, looking at the aircraft coming and going. When you get away from the airport, it's done effectively using radar feeds and software system."

The radar system acted as "highways in the sky".

"Airways controls them in the sense of managing access to the airspace and providing information to ensure people are using those highways in the sky appropriately."

When a fault was discovered in the system, the overview of what was happening in the air was no longer available, she said.

"The best thing to do is to ensure safety, which means you bring in to land aircraft that are in the air as soon as possible and you don't let new aircraft off the ground."