Pilots flying into Hong Kong's new Chep Lap Kok Airport are being urged to familiarise themselves with a new windshear alerting system, installed after a meteorological investigation revealed that severe turbulence would be encountered for a total of 20h each year.
Chep Lap Kok is adjacent to Lantau Island, which rises to 1,000m (3,300ft) and can lead to significant terrain-induced windshear, says the study.
The $1.5 million Windshear and Turbulence Warning System (WTWS) unit developed by Weather Information Technologies of the USA is undergoing operational evaluation. The Hong Kong Observatory, Hong Kong Civil Aviation Department and the International Federation of Air Line Pilots Associations (IFALPA) have also been involved.
The WTWS comprises a Terminal Doppler Weather Radar (TDWR) for detecting convective windshear with a 90% probability of detection (POD), and a Terrain-Induced Windshear and Turbulence (TIWT) predictive diagnostic tool. By fine-tuning the TDWR algorithm and feeding in anemometer data from around the airfield, researchers believe a POD increase from 50% to over 80% is possible for the TIWT element.
Control tower displays give controllers warnings for turbulence as moderate or severe, and for microburst alerts for a 30kt (55km/h) or greater headwind loss or gain. This is relayed verbally.
Introduction of WTWS warning on the flightdeck is being proposed, but there are problems to be overcome, says IFALPA, adding that pilots should watch for potential conflicts between ground-based and airborne windshear warning systems.
The WTWS is also designed for use with future data gathering from sensors such as the light-detection and ranging system LIDAR. This would increase the POD considerably, says IFALPA.
Cathay Pacific will assist in validating the WTWS in a simulator, while IFALPA hopes Jeppesen and Aerad route guides will have usage notes for pilots.
Source: Flight International
