By David Jensen
WASHINGTON, 4 March 2010. Although consulting firms design many procedures, both public and private, in the U.S. and throughout the world, the Federal Aviation Administration (FAA) continues to be the primary source for designing required navigation performance (RNP) approach procedures for the NAS.
"Third-party procedure designers have been designated to design public-use RNP AR where a non-FAA entity is willing to fund development of such a procedure," says a spokesman for the agency. Generally, this would be at location in which one or more local users or the airport authority desires a procedure completed sooner than would the FAA, which may give it a lesser priority.
According to the FAA spokesman, "As of February 2010, there have been a total of 205 RNP AR procedures published in the United States. They are for 183 runways."
Many of the approved RNP AR procedures have decision altitudes (DA) as low as 250 feet above threshold elevation. However, the spokesman adds that, while a lower DA is desirable, a major benefit of RNP is to "enable the most efficient, repeatable aircraft trajectory in various applications." Those examples include "terrain-challenged areas, such as Colorado and Alaska," he says.
Working with the aviation industry, FAA is developing a "revised strategy," to commence in Fiscal Year (FY)2011, according to the FAA official. "It will focus mainly on the integration of a set of RNAV and RNP arrival, departure and approach procedures appropriate for a given terminal or metroplex environment," he continues. "The FAA also is developing a NAS-wide plan for implementation of RNAV routes to address en-route needs."
By February, the FAA had published 341 RNAV SIDs (standard instrument departures) and STARs (standard terminal area routes). It is in the process of publishing "at least one RNAV SID and STAR, and in most cases, multiple procedures at each of the top 50 [U.S.] airports," says the spokesman.