New Wide Area Multilateration surveillance equipment to be operational in Queenstown by Jul-09


Airways New Zealand stated (06-Feb-09) a new system of aircraft surveillance, Wide Area Multilateration (MLAT) surveillance equipment, will be implemented by Jul-09, providing another “layer of safety” in Queenstown. Airways New Zealand has been working with Air New Zealand and Qantas in exploring surveillance options for Queenstown airport for over three years, the key driver being increased safety.

A new system of aircraft surveillance being installed in Queenstown will provide another “layer of safety”, according to Airways senior engineer, Roger Kippenberger. Most of the resource consents to install Wide Area Multilateration (MLAT) surveillance equipment in the hills around Queenstown have been granted. Following an extensive test period, the system will be put to work just in time for the marginal winter weather in July.

“The complex terrain surrounding the airport has meant that in the past, in- and outbound flights were extremely limited during inclement weather conditions. 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. 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” said Mr Kippenberger.

Working with Air New Zealand and Qantas, Airways has been exploring surveillance options for Queenstown airport for over three years; the key driver being increased safety. The altitudes jet aircraft have to fly because of terrain constraints in the Queenstown basin area restrict the pilot’s ability to observe other aircraft in their area, which in turn impacts on Air Traffic Controllers’ situational awareness and visibility. MLAT’s provision of surveillance of all aircraft operating within controlled airspace will significantly reduce this 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. They’ll be able to confirm pilots are where they say they are and the system can also be used to help pilots uncertain of their position. This is a service that until MLAT, we haven’t been able to offer in Queenstown” said Mr Kippenberger.

MLAT is a relatively new technology to civil aviation, though it has been used in the military for more than 50 years. Its use in Queenstown is considered ‘cutting edge’ and Airways adoption of this proven technology is regarded as being amongst the best deployment of the technology in the world currently.

MLAT works in mountainous regions because of the multiple ground stations used to give ‘visibility’ into valleys and behind mountains. In Queenstown, MLAT will consist of 14 sensor sites. These sensors can be deployed with minimal environmental impact; they are solar-powered and capable of withstanding extreme weather conditions.
“The result is a very cost effective, environmentally-friendly surveillance technology that improves safety without imposing further avionics cost burdens onto aircraft operators, and subsequently, communities.”

MLAT triggers an aircraft’s mode AC transponder, which all aircraft are required to have fitted within defined airspaces, through a ground network of receivers and transceivers that measure the time difference of arrival from the transponder signal.

Existing NZ radar systems produce updates on aircraft movements every five seconds, whereas MLat gives information on a plane’s position and trajectory every second, thus ensuring higher levels of positional accuracy and greater update rates than traditional radar.

Each of the 14 sensor sites will comprise a 70cm sensor antenna, linking equipment and either a cabinet or a small portocom to house equipment and power supply, two of the sensor sites are solar powered, and include a solar array.

Airways will install MLAT in Queenstown in during the 2009 summer, following which there will be an extensive testing period before the system becomes fully operational.

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