 Complete the following phrase:  When North Vietnamese forces captured Da Nang Air Base, at the end of March 1975, they captured large amounts of stores and equipment, including 33 intact A-37s. On 28 April 1975, several captured A-37s were used by the North Vietnamese to attack Tan Son Nhut Air Base, still held by the South Vietnamese. Approximately 187 A-37Bs were in RVNAF service at the Fall of Saigon in April 1975. Ninety-two were recovered by the US, while the other 95 were later used by the Vietnam Peoples Air Force in missions over Cambodia and during the 