Most of the resource consents to install Wide Area Multilateration (MLAT) surveillance equipment in the hills around Queenstown had been granted and installation of the 14 sites had begun. It was expected to be complete in time for the marginal winter weather in July.
The complex terrain surrounding the airport has meant that in the past, inbound and outbound flights were extremely limited during inclement weather.
"The mountains also preclude the use of traditional radar, so it has long been a strategic issue to get surveillance into Queenstown Airport, particularly with the increasing number of jet flights taking place," Mr Kippenberger said.
"The accuracy and reliability of MLAT will allow the Airways staff in the control tower to accurately know where all the aircraft are operating in the Queenstown basin area, resulting in improved safety and flight regularity for the Queenstown community.
"It's a lot cheaper than putting in radar . . . this technology is great and provides the service at a lesser cost.
"This system may help aircraft if they become disorientated [in inclement weather] - they can call the tower and identify themselves and get directions.
"It will assist controllers in providing a better operational awareness . . . they can see a picture of where everyone is, [rather than rely on audio]," Mr Kippenberger said.
Two of the sensors - which look like a power pole with antennae at the top - have been placed on Frankton Rd and others would be placed on mountain tops.
The cost of the MLAT system was being met by Airways, which had a "commercial agreement" with Air New Zealand and Qantas.
While MLAT was considered a relatively new technology to civil aviation, it had been used in the military for more than 50 years and was running in Tasmania, throughout Europe and the United States. A site in Auckland was still to be commissioned.
Its use in Queenstown was considered cutting-edge and Airways' adoption of the technology was regarded as being among the best deployment of the technology in the world.
Airways, in conjunction with Air New Zealand and Qantas, had been exploring surveillance options for Queenstown Airport for more than three years - the key driver being increased safety.
The altitudes jet aircraft had to fly because of terrain constraints in the Queenstown basin restricted the pilots' ability to observe other aircraft in their area, impacting on air traffic controllers' situational awareness and visibility, Mr Kippenberger said.
MLAT's provision of surveillance of all aircraft operating within controlled airspace would significantly reduce that risk.
"Queenstown has gone from being a relatively low-level area of aircraft activity with typically smaller aircraft, to an area servicing high-frequency jet flight operations.
"Queenstown is an evolving, growing market that has increased the complexity of air traffic control. As an advanced and proven technology, MLAT will enable air traffic controllers to provide pilots with more accurate and timely traffic information," Mr Kippenberger said.
What is MLAT?
• Wide Area Multilateration (MLAT) surveillance systemWorks in mountainous regions.
• Multiple ground stations give visibility into valleys and behind mountains.
• 14 sensor sites in Queenstown.
• Sensors have little environmental impact, are solar powered and can withstand extreme weather.
• Improves safety without imposing further costs on airlines and communities.
• MLAT triggers an aircraft's mode AC transponder which all aircraft are required to have fitted within defined air spaces, through a ground network of receivers and transceivers measuring the time difference of arrival from the transponder signal.
• Existing New Zealand radar systems produce updates on aircraft movements every five seconds - MLAT gives information on a plane's position and trajectory every second, ensuring higher levels of positional accuracy.
• Each sensor site will comprise a 70cm sensor antenna, linking equipment and either a cabinet or a small Portocom to house equipment and power supply.
• Two sensor sites are solar powered, and include a solar array.
