Explained: Why Delhi airport always fails to meet flight-handing demand
New Delhi’s Indira Gandhi International (IGI) airport, which has three operational runways, late last year clocked its peak record of handling 1,339 air traffic movements (ATMs) in a day. Even as this was significantly higher than its usual count, the number would seem rather unimpressive when compared with the 969 ATMs achieved a few days ago by the Mumbai airport, which has only one runway. Why does Delhi handle so few ATMs in a day despite three runways? There certainly is no dearth of demand – the average consolidated demand from all airlines would require the airport to handle 90 ATMs in peak hours, against the 73 that it manages at present. The problem for Delhi, it seems, lies in a number of factors. For one, though there are three runways, not all can operate simultaneously, thanks to operations complexities. Besides, some security issues and the nature of flights to and from the airport also pose some challenges that are unique to Delhi. Simultaneous operations The International Civil Aviation Organisation (ICAO) rules state that different aircraft operating on adjacent runaways must be separated by a minimum of 3 nautical miles at all times, unless some ‘mitigation measures’ have been put in place. In IGI’s case, the distance between the two runways used for arrivals is only 1.3 miles. This means there can be no parallel landing of planes on different runways at the same time – something that significantly reduces the overall capacity. Also, the situation of two of the three runways – one used for arrival and the other for departure – is such that they converge at ends. This makes them operationally dependent on each other, and simultaneous arrival and departure of planes impossible. Delhi International Airport Ltd (DIAL), the joint venture of GMR Group, Airports Authority of India (AAI), and Fraport AG operating the Delhi airport, and AAI are working together on putting in place the necessary ICAO-mandated ‘mitigation measures’ to facilitate simultaneous operations on the runways 10/28 and 11/29. These measures, used only at some of the world’s busiest airports, are designed for additional security to ensure safe parallel operations across runways. Security concerns The Delhi airport also has a large general aviation business – of smaller private planes – which accounts for three per cent of its daily ATM handling. However, the northernmost runway is barred from servicing such planes, thanks to VIP security restrictions. Since these planes do not follow a fixed schedule, they need to be accommodated on the other runways which adds more pressure on the capacity. The airport also handles 50-55 ATR aircraft, the most for any airport in the country. These account for 7-8 per cent of its daily ATM handling.
For these smaller aircraft, ICAO has stipulated a separation of up to 7 miles, if they are behind larger aircraft. This, too, exerts some pressure on the capacity.