Air China's First RNP Approach Into Linzhi Airport, Tibet

HIMALAYAN RNP

The first required navigation performance approach into this new airport in a mountainous valley is a sign of things to come as China plans to certify up to 50 more RNP procedures at terrain-challenged airports in a five-year period.

RNP procedures use advanced flight management systems and satellite navigation primarily (though in some cases DME-DME) to allow airline aircraft to drive down tightly confined corridors of airspace. Airlines and ATC agencies worldwide are starting to embrace this type of "performance-based" navigation, and China is poised to implement it on a large scale. For this RNP approach in Tibet, an Air China Boeing 757 was relying on dual GPS receivers, flight path computers and inertial reference systems so no single failure could cause a loss of navigation capability. Self-monitoring avionics systems are installed to alert pilots of any problems.

This Aviation Week & Space Technology pilot observes parts of the approach into Linzhi from the cockpit. The RNP procedure we are flying was developed by Naverus Inc. of Kent, Wash., a 50-employee company. Steve Fulton, chief technical officer of Naverus, and Buzz Nelson, who joined the company after a 31-year career as a Boeing test pilot, also are on the flight.

The recently completed 9,700-ft.-elevation Linzhi Airport is ensconced in a valley with a ridge jutting out to the left toward the approach path to one end of the 9,800-ft. runway.