With demonstrations of Automatic Dependent Surveillance-Broadcast (ADS-B) technology successfully completed at four U.S. airports in the last quarter of 2010, the FAA is preparing to complete the rollout of ADS-B ground stations nationwide.
Achievement of the so-called In Service Decision for ADS-B sites in Alaska, the Gulf of Mexico, Louisville, and Philadelphia marks a major milestone on the FAA's overall Next Generation Air Transportation System (NextGen) initiative to modernize America's National Airspace System (NAS). Because of its importance in the development of free flight, the FAA has kept the ADS-B program on track to complete the construction of all planned 794 ADS-B ground stations by 2013. Three-hundred-plus installations had already been completed as of the beginning of 2011.
One of the main benefits of NextGen is the ability for commercial aircraft to fly precision approaches into airports that are terrain-challenged or into restricted airspace such as at Reagan National Airport in Washington, D.C. Performance-based navigation (PBN) lets aircraft fly precisely defined paths without relying on ground-based radio-navigation signals. Required Navigation Performance (RNP) is an advanced form of PBN that can eliminate an average of 10 nmi from the distance an airplane flies on its approach to landing and create significant reductions in fuel consumption and CO2 emissions.
Four companies are authorized by the FAA to develop RNP procedures and work with commercial airlines and business operators to implement performance-based navigation: Jeppesen (now owned by Boeing), Naverus (now part of GE Aviation), Honeywell, and Boeing (specifically its Navigation Services group). In many instances, aircraft require special technology such as a head-up display to fly down to the minimums designed in the procedure.
GE Aviation recently introduced a pair of the newest RNP procedures to the world. The RNP paths, designed by Naverus, provide precise lateral and vertical guidance to the runway at Lijiang airport in southern China near the border with Burma.
Sichuan Airlines and Air China first flew the routes late last year when the airport's instrument landing system (ILS) was out of commission. The ability to fly into the airport without ILS helped maintain commercial air service at the airport during that time.
"Chinese airlines are proving that performance-based navigation solutions, like these RNP flight paths, solve many of today's most challenging air-traffic-management problems," said Steve Forte, General Manager of GE's PBN Services.
The precise lateral and vertical aircraft guidance afforded by RNP and GPS satellite navigation made it possible for aircraft to land at Lijiang during periods of low visibility or when cloud ceilings are below 1200 ft and there is no ILS.
In addition to the Lijiang RNP flight paths, GE worked recently with Sichuan Airlines to validate RNP paths for its fleet of A319s at Lhasa airport, located in China's Tibet Autonomous Region. The RNP paths, now in revenue service there, allow Sichuan aircraft to fly in and out of the mountainous terrain in all weather and 24 hours a day. Without RNP, the airport is accessible only during daylight hours and in good weather conditions.
In addition to Lijiang and Lhasa, GE's PBN Services business has implemented RNP paths at four other Chinese airports—Bangda, Yushu, Linzhi, and Jiuzhaigou—and has designed and deployed RNP paths for two other Chinese airlines: China Southern and China Eastern.