Six commercial models of the DC-10 were developed. All versions of the trijet transport accommodate from 250 passengers, in a typical mixed first class and coach arrangement, to 380 in all-economy seating. The roomy flight deck of the DC-10 had stations for a three-member crew, plus seating for two observers. Prime considerations in cockpit design were simplicity, efficiency and low crew workload. The DC-10 was the first commercial transport to be certified under the stringent FAA Stage 3 regulations governing sound levels for new aircraft, and it also complied with international noise standards.