air superiority over qualitatively superior Pakistan Air Force. Thus the war was effectively a stalemate. By the time of the Indo-Pakistani War of 1971, the Indian Air force had both the numerical as well as qualitative edge. Newly procured Mikoyan-Gurevich MiG-21s and Sukhoi Su-7 were also inducted into service. On the other side of the border the PAF had successfully inducted new aircraft such as the Shenyang J-6 and Dassault Mirage III. The war began with Operation Chengiz Khan, Pakistan's December 3, 1971 pre-emptive strike on 11 Indian airbases. After the initial pre-emptive strike, the PAF adopted a defensive stance in response to the Indian retaliation. As the war progressed, the Indian Air Force continued to fight the PAF over conflict zones, but the number of sorties flown by the PAF gradually decreased day-by-day. The Indian Air Force flew 4,000 sorties while its counterpart, the PAF offered 3,300 in retaliation, partly because of shortages of non-Bengali technical personnel. In East Pakistan, the lone No. 14 Squadron Tail Choppers of the PAF pitched against ten IAF Squadrons was ultimately grounded, when the Tezgaon airfield in Dhaka (Dacca) was put out of commission after seven days of repeated bombings by Indian MiG-21s, Hunters and Su-7s, and consequently allowed the IAF to attain air superiority in the East. Vietnam War The Republic of Vietnam Air Force (VNAF) was originally equipped with helicopters such as the Piasecki CH-21 and propeller powered aircraft such as the North American T-28 Trojan when jet aircraft were disallowed by treaty. As US involvement increased, most aircraft were flown by US forces. Large scale use of helicopters by the US Army in Vietnam led to a new class of airmobile troops, and the introduction of "Air Cavalry" in the U.S, culminating in extensive use of the Bell UH-1 Huey helicopter which would become a symbol of that war, while the Sikorsky CH-54 Tarhe "Skycrane" and Boeing-Vertol CH-47 Chinook lifted heavier loads such as vehicles or artillery. Troops were able to land unexpectedly, strike, and leave again, and evacuate wounded. The specialized AH-1 Cobra was developed from the Huey for escort and ground support duties, The later Soviet campaign in Afghanistan would also see widespread use of helicopters as part of the Air Assault brigades and regiments. US forces provided close support of ground force over South Vietnam, and strategic bombing of targets over North Vietnam. Many types flying close