Successful flight tests of Ground Based Augmentation System (GBAS) landing approaches at Frankfurt and Toulouse-Blagnac Airports represents the Single European Sky ATM Research (SESAR) program's goal of replacing legacy Instrument Landing System (ILS) approaches with satellite based approaches at airports throughout Europe.
A computer generated rendering of an airplane runway approach using Honeywell's Smartpath system. Photo, courtesy of Honeywell.
In September, SESAR partnered with Honeywell, Airbus, Thales, DFS and Eurocontrol to carry out flight tests with a Dassault Falcon 900EX business jet using GBAS CAT II/III ground equipment (GASTD) at both Frankfurt and Toulouse. The successful flight tests demonstrated that Category II/III approaches are achievable using the GASTD system based on a unique constellation and mono frequency signal, according to a statement from SESAR.
Different scenarios including multi path evaluations, full scale deviations and CAT III to II regression testing and back were evaluated during the flight trials, in an effort to prove the validity of GBAS, proving that an airborne receiver installed on the Falcon 900EX could integrate seamlessly with the different ground stations at both airports. The flight tests also validated work that was done over the past 10 months by the project partners to ensure that CAT III avionics receiver prototypes can integrate with prototypes for ground stations and airport air traffic control infrastructure.
The full validation cycle of the system and procedures has not been completed yet; although when it is validated and certified by the European Aviation Safety Agency (EASA), SESAR will look to replace legacy ILS systems at airports throughout Europe. ILS technology was first introduced in the U.S. in the 1930s, and while reliable, it simply cannot handle the future projected increase in air traffic in Europe and around the globe.
"ILS technology was first explored back in the late 1930s, and then it came into widespread use when newer airplanes were built and newer avionics were put onboard," said Sean Cassidy, first vice president of the Air Line Pilots Association, International (ALPA) and a commercial Boeing 737 pilot. "And its worked very well, but it has limitations. First of all there's installation costs, there's maintenance costs, and ILS signals can't bend around mountains, they can't go through mountains, they can't avoid obstacles, so basically an ILS approach is a straight-in approach to a runway point."
For those reasons, among others, both the SESAR program in Europe and FAA's NextGen modernization in the U.S. are moving towards a satellite-based air traffic management system.
Honeywell's Smartpath system is the first GBAS system to be certified by the FAA for CAT I landings, and they're currently developing it for CAT III. The system allows aircraft to land in conditions where there is a half-mile visibility at a 200 foot decision height on approach. The system, and all GBAS systems, are designed for aircraft equipped with GPS landing system technology. Most Airbus and Boeing current production commercial aircraft are equipped with GBAS avionics, or feature optional upgrades.
GBAS systems also present significant cost savings for airports and airlines that have to pay Air Navigation Service Providers (ANSPs) to use landing systems. According to Honeywell, one Smartpath system installed at a typical airport can yield savings of up to $400,000 annually in maintenance savings as compared to using ILS.
"That's why we're moving towards a satellite based navigation system and operation system for the National Airspace System (NAS)," Cassidy said, referring to FAA's NextGen program. "By putting more of the equipage on the airplane and relying less on the equipage on the ground, you're creating a lot more efficiency. You don't have to worry about maintaining thousands of ground based beacons and ILS stations."
Going forward, SESAR plans on performing the same flight tests with commercial aircraft, with an ultimate goal of using CAT III GBAS approaches throughout Europe on commercial flights. Further testing for Toulouse and Frankfurt is scheduled for mid-2014.