Severe wind shear (headwind change of 30 kn or more) at Hong Kong International Airport is documented in this study. Its climatology, including the number of reports from pilots each year, captured by the wind shear alerting service, its cause and its magnitude are presented. The purpose of the study is to document the characteristics of severe wind shear at an operating airport. Some typical cases of severe wind shear are also examined, such as observation by remote-sensing instruments and flight data analysis. It is found that the shear magnitudes in pilot reports of severe wind shear, as with pilot reports of wind shear in general, are subjective in nature. They may not be consistent with headwind changes as determined from the flight data. Sometimes, the pilot reports of wind shear may be based on wind trend information available onboard for certain fleets of aircraft. The wind shear can be transient in nature, for which an alert beforehand is difficult.
