On 15 October, Air India adjusted the routing of its Delhi—San Francisco flight to increase the distance of the flight by over 1000 kilometers. In doing so, however, the airline saved 2 hours and 15 minutes of flying time. How did they manage that? In a word: wind.
Flying the Jet Stream
Prior to this week, Air India’s flights between Delhi and San Francisco took a polar routing in both directions, flying north from Delhi over the North Pole and south through Canada. From 15 October onward, flight 173 is flying east from Delhi through China and over the North Pacific Ocean to take advantage of the Jet Stream, the high-altitude, fast moving air used by other flights crossing the Pacific.
While the distance flown will increase by over 1000 kilometers, depending on the speed of the wind, the flight will be between one and three hours shorter than the old polar route. Taking advantage of the tailwind offered by the jet stream on this route will also help the airline cut the amount of fuel it uses during the flight. Air India made the change after receiving approval from India’s Director General of Civil Aviation to operate on the NOPAC and PACOTS tracks that cross the Pacific Ocean.
The return from San Francisco will still fly north from San Francisco on a polar routing.