GRAHAM WARWICK / WASHINGTON DC
Carriers urge FAA to make development of arrival and departure procedures a priority
US airlines have cautioned the Federal Aviation Administration not to overlook the benefits of basic area-navigation (RNAV) in its new push for a performance-based airspace system. Carriers are concerned the basic RNAV capability of most US airliners will be ignored as the FAA pursues the advanced procedures possible with required navigation performance (RNP) RNAV.
About 80% of the US airliner fleet is equipped for basic RNAV, but only a handful of procedures have been approved. This contrasts with Europe, where RNAV is required in almost all en-route airspace and is planned to be extended to terminal airspace by 2010. At an RTCA symposium in Vienna, Virginia last week, Ira Pearl, Delta Air Lines' director of flight operations technical support, urged the FAA to make development of RNAV arrival and departure procedures "a priority".
Under its performance-based national airspace system initiative, the FAA is moving to exploit the capacity and efficiency benefits of RNP RNAV, which differs from basic RNAV in that it provides navigation containment - the aircraft is able to monitor its navigation performance. This allows advanced procedures, such as simultaneous converging approaches, but requires dual-redundant avionics. Less than half of the US fleet is RNP-capable.
"Before you ask me to spend more, give me value for what I've already paid for," said Pearl, criticising the FAA's lack of progress with basic RNAV. Eleven RNAV "Q routes" have been opened on the US West Coast, but their use is restricted to GPS-equipped aircraft. The routes will be opened to aircraft using DME/DME navigation in August, Jeff Williams, FAA RNP division manager, told the symposium. More RNAV arrival/departure procedures will be released soon, he says.
The containment provided by RNP will allow advanced RNAV approach procedures, available to operators that comply with the special aircrew and aircraft authorisation required (SAAAR) - similar to the approval needed to use a Category 2/3 instrument landing system, the FAA says. These include the RNP parallel approach transition (RPAT), which will improve access to runways spaced 1,300m (4,300ft) or less apart, due to be implemented at seven airports by 2005.
Roland Rawlings, navigation domain manager with Eurocontrol's airspace, flow management and navigation unit, told the symposium that Europe plans to introduce precision RNAV in terminal airspace in 2010 and four-dimensional RNAV, allowing "full gate-to-gate management of the flight", by 2015. "The USA is losing its pace-setter status," warned Delta's Pearl.
Source: Flight International
