Operational Constraints on Flight Navigation due to Fog and Consequent Economic Implications at the Rajiv Gandhi International Airport, Hyderabad, Telangana, India

Fog is a frequent deterrent during the winter season. The reduction in horizontal visibility and other adverse conditions results in flight delays, cancellations, and flight dc-route/diversions, leading to economic implications for rescheduling plans by the air-travellers. Clear skies, calm/light winds, a good amount of relative humidity, and fall in temperatures due to radiation cooling during winter nights are conducive. The intensity and duration of fog constrain flight operations. In the light of a fair number of fog occurrences compelling flight delays and diversions over Hyderabad Airport (RGIA, Shamshabad), the present study is undertaken to analyse the meteorological aspects of fog. and its frequency, duration, and economic implications. During the period 2014-2019, 74 instances of fog occurrence were recorded over the RGIA. The majority of the incidents (45.9%) were shallow fog events. The dense fog (2) and very dense fog (1) events were rare. Maximum fog occurrences (26 out of 74 events) were reported in December. The onset of fog was observed between 1800 UTC and 0400 UTC, while most of them (43.2%) occuired between 0000 UTC and 0200 UTC. Most of the fog events lasted up to 1 hour, and there were six instances of fog lasting between 2-3 hrs.