So Long RNAV!
- John Frazier
ADS-B (Automatic Dependent Surveillance - Broadcast) — The satellite-based, data-linked system that will replace the current ATC radar-based management of the National Airspace System. ADS is happening now in the U.S., with full implementation mandated by 2020. FAA rulings on equipment standards and implementation dates are in place. Basically, “everybody can see everybody” in a fully implemented ADS world. Safety, energy efficiency, and reduced costs will all be big winners.
OPD (Optimized Profile Descent) — In 2009, the FAA began to conduct tests of the OPD procedure in Alaska. OPD aircraft are issued a ‘descend via’ clearance, allowing the pilot, using the FMS, to select the Top of Descent point that provides the best operating efficiency for the arrival. Throttles are in flight idle all the way down, with no intermediate level offs. Fuel, time, and workload savings are substantial. RNAV STAR OPDs are now in place at a number of major U.S. airports, including Phoenix, Los Angeles, San Diego, Atlanta, and Las Vegas, with more on the way.
RNP (Required Navigation Performance) approaches can be significantly more efficient and to lower minimums. Because of the increased precision, allowed turning, vertical containment, and crew monitoring and alerting features, RNP approaches may be installed at airports that do not meet traditional TERPS approach requirements, especially in mountainous locations. RNP approaches will replace NDB and VOR approaches in the U.S over time. You will see more and more of them in your approach plates.
Satellites — Our U.S. GPS is not the only one! Europe (Galileo is currently launching via Russian Soyuz rockets), Russia (GLONASS), China (Compass), India (IRNS), and Japan have all either developed, are deploying, or are considering deploying global navigation satellite systems.
WAAS (Wide Area Augmentation System) is basically a more precise GPS system. Ground-based locations do the enhancement work. WAAS has the advantage of providing a GPS-based electronic glide path and the DA minimums that go with it (LPV minimums) including down to 200 and ½. Many new aircraft are WAAS equipped as WAAS will replace ILS in the U.S. over time.
That’s it for now, but stay tuned as “The Times They Are A’changin’”.