The Civil Aviation Authority of Nepal (CAAN) has published an Aeronautical Information Publication (AIP) amendment for the entry into service of new RNP AR approaches and departures developed by NAVBLUE for Tribhuvan International Airport (IATA: KTM, ICAO: VNKT), the main airport serving Kathmandu, which is surrounded by mountains and a very challenging operating environment.
Required Navigation Performance with Authorization Required (RNP AR), a Performance Based Navigation (PBN) navigation specification, is a good solution for this type of airport. RNP AR allows navigation accuracy down to 0.3NM and below, and performing turns after the final approach point: trajectories can fit better in the obstacle landscape, reducing minimas while maintaining safety.
NAVBLUE had already developed RNP AR procedures in 2012 for Runway 02 at Kathmandu Airport, which includes Radius to Fix (RF) turns in the final segment to allow a curved approach around the mountains, as opposed to the straight-in VOR approach (VHF omnidirectional range) usually required to go over a mountain. These RNP AR procedures allow a comfortable glide slope of 2.8 degree compared to the VOR glide slope of 5.3 degree.
The new RNP AR APCH procedures designed by NAVBLUE in 2021 for Runway 20 at Kathmandu airport offer an IFR (Instrument Flight Rules) alternative to the current VFR (Visual Flight Rules)/circling approaches. RNP AR departure procedures for both runway ends have also been developed providing full benefits to operators equipped with this capability, NAVBLUE says.
The new RNP AR procedures, airlines flying to and from Kathmandu airport will benefit from lower approach minima and fewer weather related diversions, a fully guided approach in both lateral and vertical (using flight director and/or autopilot), optimized airspace with fully repeatable, predictable trajectories and reduced fuel consumption due to shorter procedures compared to the conventional ones, and optimized vertical paths of the trajectories.
“NAVBLUE is proud that Kathmandu airport will now benefit from new RNP AR procedures, which should generate significant benefits for airlines flying into Nepal,” said Fabrice Hamel, CEO of NAVBLUE. “For Runway 20 it even allows for instrument flight procedures where none existed before. These fully managed RNP AR procedures reduce the risk of unstabilised approaches and involve fewer go-arounds, bringing operational benefits for the airport, both in terms of efficiency and safety.”
NAVBLUE says it has already supported many airlines in their ops approvals, Flight Ops Safety Assessment (FOSA), RAIM predictions and navigation database validation for their RNP AR operations into Kathmandu, in order to enhance the regularity and safety of their operations in their flights to Kathmandu.
IndiGo, India’s largest airline, has chosen NAVBLUE and Airbus’s RNP AR modification to upgrade some of its latest A320 aircraft and to obtain RNP AR approvals to take advantage of the new procedures. Kathmandu is the only international airport in Nepal.