As a result of the United States rebuff, Saudi Arabia turned to Britain to meet its requirements. In mid-1988, it was announced that as part of a huge transaction, Saudi Arabia would acquire Tornado fighters from Britain in their strike and air defense configurations, plus Hawk jet trainers and Pilatus PC-9 trainers built in Switzerland and outfitted in Britain. Project Al Yamamah is Britain’s largest export contract assisting the Royal Saudi Air Force to become self sufficient. As of early 1992, three of the RSAF fighter-ground attack squadrons were equipped with Tornadoes and three squadrons were equipped with F-5Es. Two air defense squadrons were equipped with Tornados and three squadrons were equipped with F-15Cs. The three transport squadrons were equipped with C-130s in various versions and CASA C-212s, a medium transport of Spanish design. The two helicopter squadrons employed a variety of smaller rotary-wing aircraft. Undaunted by its previous failure to establish an assured supply of combat aircraft from the United States, Saudi Arabia announced in late 1991 that it had placed an order with McDonnell Douglas for an additional seventy-two F-15s. It appeared doubtful whether the sale would be approved by the United States administration and the Congress.