Manoeuvring delicately at a height of 17,000 feet and at a speed of 500 km an hour, the powerful Su-30 jet fighter sidles up the huge Il-78 aircraft that can best be described as a flying fuel tank.
Extending a short probe located ahead of the cockpit, the Su-30 moves closer and locks on to a pipe extended from a pod attached to the 75-tonne Il-78, sucking in several tonnes of fuel in a matter of minutes.
During the entire procedure, both aircraft maintain the same distance and speed.
The refuelling complete, the Su-30 peels away, able to remain in the skies for several more hours and capable of flying several more thousands of kilometres.
It is this capability, said Air Commodore R.C. Baruah -- commander of the Agra airbase where the India's four Il-78 mid-air refuelling aircraft are based -- that will allow the Indian Air Force (IAF) to project power on a global scale.
Baruah knows what he is talking about.
The IAF is only the world's sixth air force to acquire mid-air refuelling aircraft. By refuelling in the sky, frontline jets like the Su-30 can almost double their range of 2,500 km, making them capable of striking at targets deep within China.
In just a little more than 18 months since the IAF acquired the Il-78s from Uzbekistan, the aircraft have helped jet fighters to make long journeys to Alaska and South Africa to join international military exercises.
"The Il-78s are helping maximise the IAF's offensive potential and flexibility for tactical operations," Group Captain Shouvik Roy, commander of the Mid-Air Refuelling Squadron (MARS), told a group of journalists.
Currently, the IAF's Su-30, Mirage 2000 and Jaguar jets have the capability to refuel in the air.
Pilots are being trained round the clock to acquire the expertise required to hook up to the Il-78s -- each of which can carry 110 tonnes of fuel and refuel three jets at a time -- and take in several tonnes of fuel in about five minutes.
Those flying the Su-30s, Mirages and Jaguars are considered among the best of IAF pilots, but even they need to train for several months to simply become capable of hooking up with the flying fuel tankers. Only after this are they allowed to refuel in mid-air.
"We have flown 2,300 hours in training missions since May last year, made 4,800 engagements (mid-air refuelling contacts) and delivered over 2,300 tonnes of fuel," said Roy.
While the Il-78s were bought from Uzbekistan, the refuelling pods, three of which are fitted on each aircraft, were acquired from Israel. With four Il-78s already in operation with the IAF, the force will receive two more refuelling aircraft from Uzbekistan next month.
Roy said his unit had framed its operational procedures from scratch, as the IAF had no experience of flying mid-air refuelling aircraft.
"We have learnt concepts from the Israelis, as well as the Royal Air Force and US Air Force during our recent exercises with them," Roy said. "We will also soon interact with the navy (to train for mid-air refuelling).
"While refuelling, we can't relax even for a second. We have to be continuously alert because we have to coordinate with up to three jets."
The Il-78s are now capable of carrying out refuelling missions over land and sea, during both day and night, Roy said.
During recent training missions, said an officer who did not want to be named, Su-30 jets based at Pune in Maharashtra flew close to Tezpur in Assam in the northeast, a distance of over 2,100 km, with a single mid-air refuelling.
The IAF has also had to adopt innovative tactics to cope with the needs of pilots flying longer hours after refuelling.
"Our aim is to provide up to five hours of flying for jets like the Su-30. So the pilots have been provided food and water," said the officer.
"They were also provided diapers as that was the only way to relieve themselves in the air!"