The professional standards, capability and flexibility of the much expanded Service were soon to be put to the acid test. From early 1971, as the political situation on the sub-continent deteriorated, the IAF was alerted to the possibility of another armed conflict. For some weeks in November, both Indian and Pakistangovernments protested violations of national airspace along the western border, but aerial conflict between the respective air arms began in earnest on 22 November, preceding full-scale warfare between India and Pakistan by 12 days. At 1449 hours, four Pakistani Sabres strafed Indian and Mukti Bahini positions in the Chowgacha Mor area, and 10 minutes later, while engaged on a third strafing run, the Sabres were intercepted by four Gnats from No. 22 Sqn, a detachment of which was operating from Dum Dum Airport, Calcutta. During the ensuing melee, three of the Sabres were shot down, all Gnats returning to base unscathed. The first blood of a new Indo-Pakistan air war had been drawn. Other encounters were to follow over the next 10 days, within both Indian and Pakistani airspace, before full-scale war began on 3 December. Pre-emptive strikes were launched by the Pakistan Air Force against IAF bases at Srinagar, Amritsar and Pathankot, followed by attacks on Ambala, Agra, Jodhpur, Uttarlai, Avantipur, Faridkot, Halwara and Sirsa. Apart from IAF bases, the PAF attacked railway stations, Indian armour concentrations and other targets. In response and during the ensuing two weeks, the IAF carried out some 4,000 sorties in the West from major and forward bases in Jammu, Kashmir, Punjab and Rajasthan, while, in the East, a further 1,978 sorties were flown.
Throughout the conflict, in which Indian strategy was to maintain basically defensive postures on the western and northern fronts whilst placing emphasis on a lightning campaign in the east, the IAF established a highly credible serviceability rate which exceeded 80 per cent. Mission emphasis throughout was on interdiction. In the West the IAF's primary tasks were disruption of enemy communications, the destruction of fuel and ammunition reserves, and the prevention of any ground force concentrations so that no major offensive could be mounted against India while Indian forces were primarily engaged in the East. On the Eastern front, the Indian forces launched a sophisticated campaign which included rapid-moving infantry and armour advancing from three directions, airborne and heliborne assaults, missile bombardments from ships and an amphibious landing, the IAF's task being primarily direct support of the ground forces. In a classic air action in the Western desert, four Hunters of the OCU, detachment at Jaisalmer destroyed an entire armoured regiment at Longewala, literally stopping the enemy offensive in its tracks.
The IAF had good reason for satisfaction with its showing during the December 1971 conflict. Although Pakistan had initiated the war with pre-emptive air strikes against major forward air bases, the IAF rapidly gained the initiative and had thereafter dominated the skies over both fronts. Admittedly, there had to be war losses but the IAF flew many more sorties than its opponent with interdiction missions predominating, and the bulk of the Service's attrition was the result of intensive anti-aircraft fire; in aerial combat, the IAF proved its superiority in no uncertain manner. First round had gone to the Gnats, again, but its later compatriots, the MiG-21s, were to shortly demonstrate the superiority of this supersonic fighter, flown by professionals. Six squadrons of MiG-21FLs were part of the IAF's order-of battle, participating in operations both in the Eastern and Western Sectors. Three MiG-21 squadrons, operating from Gauhati and Tezpur,took part in counter-air, escort and close air support tasks during the blitzkrieg action in Bangladesh. That the MiG-21 was highly effective in short range, precision attacks was amply demonstrated during the attacks with 500 kg bombs on the PAF's air bases at Tezgaon and Kurmitola, while pin point 57 mm rocket attacks were carried out against key command centres in the capital Dacca itself.
It was in the Western theatre that the MiG-21 was employed in its primary task, that of air defence, escort and interception. Deployed at all the major air bases, from Pathankot in the north to Jamnagar in the South Western area, the MiG-21FLs mounted hundreds of combat air patrol sorties over Vital Points (VP) and Vital Areas (VA), flew escort missions for bombers and strike fighters and were continuously scrambled to intercept hostile intruders. The MiG-21 finally met its original adversary, the F- 104 Starfighter, in air combat over the Subcontinent during the December 1971 conflict and in all four recorded cases of classic dog fights, the MiG-21s outclassed and out fought the F- 104s. The first aerial victory was on 12 December 1971, when MiG-21FLs of No. 47 Squadron shot down a PAF F-104 over the Gulf of Kutch and this was followed by three more victories in quick succession on 17 December, when MiG-21FLs of No. 29 Squadron escorting HF-24 Maruts, shot down intercepting F-104s near Uttarlai in the Rajsthan desert in gun-missile encounters, while a third F-104, on an intruding mission, was shot down by another MiG 21FL of No.29 Squadron.
The December 1971 war also meant the gaining of India's highest award for gallantry to the IAF. Flying Officer Nirmal Jit Singh Sekhon, flying Gnats with No. 18 Squadron from Srinagar, was posthumously awarded the Param Vir Chakra. Notwithstanding the successful campaign of December 1971 which created both history and geography, the Indian Air Force had lessons to draw from subsequent analyses of the conflict, although for the most part, these lessons dictated refinement rather than any fundamental change.