Under memorandum of understanding, Boeing 737 will demonstrate technology to improve non-precision accuracy

Chinese and Indonesian consortia are planning tests with Boeing 737s fitted to required navigation performance (RNP) standards to improve non-precision approach and departure accuracy at the countries' secondary airports.

Fitted for RNP, an aircraft can be flown to a lateral accuracy of ±0.15nm (0.28km) in terminal airspace using inertial and global positioning system (GPS) data inputs to its flight management computers (FMC) without the use of ground navigation aids.

However, the system can also integrate distance-measuring equipment (DME) and/or VOR inputs to boost integrity. VOR/DME signals are essential in areas that have not yet been mapped to the WGS84 standard of accuracy.

As a result, decision height on non-precision approaches under certain conditions can be as low as 75m (250ft) above airfield level. The use of RNP can also help lower the risk of controlled flight into terrain accidents because it provides pilots with glideslope information at airports not equipped with instrument landing systems.

DGAC, Indonesia's civil aviation authority, has signed a memorandum of understanding (MoU) with the International Air Transport Association (IATA), Garuda, Smiths Aerospace and the UK avionics manufacturer's Asian distributor Janco, Singapore, to start trials with a 737 at Jakarta from March.

Under the MoU, RNP area navigation (RNAV) runway approaches will be conducted at Jakarta airport to demonstrate the technology, with IATA providing operational support. DGAC aims to have 10 airports in Indonesia approved for RNAV operations by December. It is still unclear how the DGAC will fund development of RNP RNAV procedures and staff training.

The Chinese civil aviation authority is expected to shortly sign an MoU with Boeing, Janco and Smiths. Boeing 737 RNP trials will take place at Tianjin airport near Beijing later this year.

China plans to implement RNAV initially in the south-west region because it lacks precision navigation aids. However, China does not want to rely on the US-controlled GPS constellation, and has not mapped its territory to WGS84 standards. Consequently it anticipates using only inertial and DME inputs to the FMC which will degrade the system's accuracy to 0.3nm or more.

Janco is proposing that Indonesian flag-carrier Garuda and several Chinese airlines upgrade the FMC on their Boeing 737 fleets to enable them to take advantage of RNAV.

Discussions on how RNAV should be used in terminal airspace are also under way in Malaysia and the Philippines.

Source: Flight International