also from Tan Son Nhut completed almost 700 reconnaissance sorties, with RVNAF pilots flying O-1 Bird Dogs and U-17 Skywagons. At 01:15 on 18 February a VC rocket and mortar attack on the base destroyed 6 aircraft and damaged 33 others and killed one person. A rocket attack the next day hit the civilian air terminal killing one person and six further rocket/mortar attacks over this period killed another six people and wounded 151. On 24 February another rocket and mortar attack damaged base buildings killing four US personnel and wounding 21. On 12 June 1968 a mortar attack on the base destroyed two USAF aircraft and killed one airman. The Tet Offensive attacks and previous losses due to mortar and rocket attacks on air bases across South Vietnam led the Deputy Secretary of Defense Paul Nitze on 6 March 1968 to approve the construction of 165 "Wonderarch" roofed aircraft shelters at the major air bases. In addition airborne "rocket watch" patrols were established in the Saigon-Biên Hòa area to reduce attacks by fire. Vietnamization and the 1972 Easter Offensive On 2 July 1969 the first 5 AC-47 Spooky gunships were handed over to the RVNAF to form the 817th Combat Squadron which became operational at the base on 31 August. In 1970, with American units leaving the country, the RVNAF transport fleet was greatly increased at Tan Son Nhut. The RVNAF 33rd and 53rd Tactical Wings were established flying C-123 Providers, C-47s and C-7 Caribous. In mid 1970 the USAF began training RVNAF crews on the AC-119G Shadow gunship at the base. Other courses included navigation classes and helicopter transition and maintenance training for the CH-47 Chinook. By November 1970, the RVNAF took total control of the Direct Air Support Centers (DASCs) at Bien Hoa AB, Da Nang AB and Pleiku AB. At the end of 1971, the RVNAF were totally in control of command and control units at eight major air bases, supporting ARVN units for the expanded air-ground operations system. In September 1971, the USAF transferred two C-119 squadrons to the RVNAF at Tan Son Nhut. In 1972, the buildup of the RVNAF at Tan Son Nhut was expanded when two C-130 Hercules squadrons were formed there. In December, the first RVNAF C-130 training facility was established at Tan Son Nhut, enabling the RVNAF to train its own C-130s pilots. As more C-130s were transferred to the