S. Pudasainee, Central Department of Hydrology and Meteorology, Nepal

Mountain flight remains a considerable challenge in Nepal. Since 1979 A.D, there has been 36 helicopter accidents over different parts of the country that have claimed 85 lives. A detailed understanding of meteorological condition and reliable forecast that may develop over the complex terrain of the mid-hills of Eastern Nepal Himalaya is yet to be achieved. This research numerically discusses the near-surface unstable atmospheric conditions possibly associated with the most recent fatal crash at Pathivara Peak on 27 Feb 2019 as revealed by the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) Model routine forecast. The model simulations suggested a strong gusting wind along with snowfall and turbulence which led to inadvertently enter into Instrumental Meteorological Condition (IMC) conditions, lost situational awareness and positive control of helicopter which ultimately led to the Controlled Flight Into Terrain (CFIT) accident and ended with the tragic crash. Atmospheric instability was hazardous for aviation as well as the tourism sector in Nepal. This indicates WRF-ARW forecasts can be customized to generate and disseminate useful information of the meteorological condition to the pilots in advance for enhancing aviation safety.