Tag Archives: SAAAR

EXPLAINER: Avionics at the leading edge of performance navigation

Aviation International News has an outstanding wrap-up of the state of flight management systems (FMS) that offer  easy pilot control and core capabilities that set the stage for performance-based navigation (PBN).

Flight management systems have never been considered simple pieces of equipment, but the technology is quickly evolving beyond basic navigation and performance functionality to include a host of new capabilities that hold the promise of changing the way pilots fly for the better.

Absent from some of the latest integrated avionics systems are the bezel-mounted control display units (CDU) flight crews have known since the 1970s. Instead, many modern business jets and some of the latest airliners are integrating FMS controls with the flight displays and cursor control devices (CCD), allowing pilots to point and click their way through a variety of menus or drag and drop any portion of their flight route (a technique known as “rubber-banding”) to include or modify a waypoint. The changes are resulting in cockpits that are more intuitive than those of the past–and even those of the present, in many cases–while packing more capability than ever before.

At the same time, hardware and software upgrades available from FMS manufacturers are opening the possibilities for complex, curved RNP (required navigation performance) procedures and the latest WAAS LPV (lateral precision with vertical guidance) approaches. The changes expand the operational capabilities of properly equipped airplanes today while serving as a cornerstone for future operations in so-called NextGen airspace.

Required navigation performance will be a key element of NextGen airspace. The benefit of a so-called RNP SAAAR [special aircraft and aircrew authorization required] approach is that it can carve out a highly precise, curved path through the sky that usually results in lower landing minimums–sometimes much lower. But gaining approval is a costly and complex endeavor requiring submittal of monthly operational reports to the FAA, pilot simulator training and operations manual revisions. Considering that fewer than 100 RNP SAAAR approaches have been published so far, most operators probably won’t go to the trouble of gaining approval until their home airport has an RNP approach. But as more RNP procedures are created, operators who forego such approvals will be at a disadvantage compared with those who are SAAAR compliant.

To assist operators seeking to upgrade to RNP capability, Honeywell has launched Go Direct, a consulting service designed to help business jet operators take advantage of new RNP SAAAR procedures the FAA is adding at scores of airports around the U.S. The agency plans to publish 60 new RNP SAAAR procedures per year for the next two years. Some airports scheduled to receive an RNP approach in the next 12 months include Teterboro, N.J.; Aspen and Eagle, Colo.; Monterey, Calif.; and Scottsdale, Ariz. If your home airport or an airport you use often offers an RNP SAAAR approach, the approval can mean the difference between landing or having to execute the missed approach and consider other options.

The major advantage RNP procedures have over other types of approach is their tighter lateral boundaries, which allow the creation of curved pathways through mountain valleys or by using so-called radius-to-fix (RF) turns to avoid terrain or obstacles. The RNP SAAAR approach to Atlanta DeKalb-Peachtree Airport (PDK) is a good example of the benefits RNP can provide. The approach to PDK’s Runway 2R incorporates a continuous descending turn designed to avoid the tall towers that block the straight-in approach to the field. Due to the east-west flows at nearby Hartsfield-Jackson International, a straight-in ILS or WAAS LPV approach to this runway would be hard to implement, even if the obstacles southwest of the airport were removed.

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