As the FAA advances implementation of fuel-saving navigation procedures, the agency is running into challenges with establishing priorities, conducting environmental reviews and addressing mixed equipage concerns.
The FAA needs to prioritise which procedures to create and in what order as the agency receives more requests for area navigation (RNAV) and required navigation performance (RNP) procedures, said Rick Day, FAA Air Traffic Organisation senior vice president of operations, during a 29 July US House Aviation subcommittee hearing.
In addition, some proposed RNAV and RNP procedures remain in limbo due to needed environmental assessments.
Day explains that while some procedures essentially overlap current air traffic patterns, others require more timely environmental reviews because the location and number of proposed flight paths may be different from what currently exists.
Environmental issues aside, aircraft equipage will also be challenging, he says, explaining that air traffic controllers are bound to work with aircraft featuring varying RNAV/RNP capabilities as RNP equipage is not universal among US carriers.
As a result, a "hybrid environment" will present additional challenges to controllers, he says.
As the FAA sorts through these issues, the agency in coming weeks will begin mapping all performance-based navigation (PBN) processes to standardize how it develops, tests, charts and implements PBN procedures, Day says, noting that FAA currently only has a process for developing RNAV/RNP procedures in the airport terminal area.
Since 2002, the FAA has implemented 159 RNAV routes, which enable aircraft to fly on any desired enroute flight path within the coverage of ground- or spaced-based navigation aids, within the limits of the capability of the self-contained systems, or a combination of both capabilities. RNAV routes cover procedures for the high-altitude portion of a flight.
At the same time, FAA has also created 270 RNAV arrival and departure procedures, which define a lateral and vertical path either to an airport from the airway, or from an airport to the airway.
RNAV procedures are on top of the 163 RNP special aircraft and aircrew authorization required (SAAAR) approvals that the FAA has implemented since 2002.
By the end of fiscal year 2009, the agency plans to implement 48 other RNAV routes, 35 RNAV arrival and departure procedures and 29 RNP SAAAR approach procedures.