The Air Traffic Control has adopted a new method to ease congestion at the Indira Gandhi International Airport (IGIA) during dense fog. Bigger aircraft are being given priority clearance for takeoff and landing because this leads to better visibility at the airport.
A high-capacity, wide-body aircraft like Boeing 747 or even a medium-capacity aircraft like Airbus A-320 is being given preference for takeoff and landing at IGIA.
A senior air traffic controller said that the RVR (Runway Visual Range — the maximum distance at which the runway or the specified lights or markers on it are visible to the pilot) at the airport improves considerably at the airport after a jumbo jet takes off because the hot and high-pressure exhaust fumes it emits help clear the fog to an extent.
"The fog is made up of water droplets suspended in the air. The heat of the fumes emitted by a big aircraft during takeoff and even landing helps in the evaporation of these droplets," said an airport official.
"This is a temporary measure adopted at the airport due to the fog situation. Each jumbo takeoff leads to an increase of 50 metres in the RVR," said the air traffic controller. The increase is not insignificant because an increase in RVR from 350m to 300m means a change from CAT III-A ILS to CAT II.
"This is a new measure we have taken at the airport and it is helping in improving the RVR," said Director General of Civil Aviation Kanu Gohain.