The next-gen GPS-based air traffic control system: A primer

Ashwin Tombat
04 September 2007

It's worked in Alaska, and the FAA thinks it will solve the USA's flight delay problem. But it will cost $20 billion, and no one wants to foot the bill. By Ashwin Tombat

The futuristic, next-generation nationwide air traffic control system, for which the Federal Aviation Administration (FAA) plans to award a $1 billion contract this week, has been operating on a small-scale, limited basis in parts of Alaska for the past five years.

It has got a big thumbs up from Peninsula Airways (PenAir), the largest commuter airline in Alaska, eight of whose 40 aircraft presently use the system. The technology it will use is "truly amazing", say PenAir officials.

For the past five years, PenAir has operated under a special air traffic control system called Capstone, which the FAA developed specially for western and southeast Alaska. The system relies on the Global Positioning System (GPS) to control air traffic.

It provides moving maps that pilots in the cockpit can monitor to avoid collisions with other aircraft, or with mountains. Not surprisingly, it has dramatically improved flight safety in the remote northern state. The airline's fleet includes 40 aircraft, eight of which are equipped with the system.

Improved safety
Capstone has reduced accident rates by 47 per cent in western Alaska, where it is presently operational. The FAA estimates that state wide use could cut the overall accident rate by a third.

To use the system, each aircraft has to be fitted with an Automatic Dependent Surveillance-Broadcast (ADS-B) avionics suite. It uses GPS signals to automatically determine its location and then transmits that location to ground stations and to other aircraft equipped with the technology in its vicinity.