 The 747-100B model was developed from the -100SR, using its stronger airframe and landing gear design. The type had an increased fuel capacity of 48,070 US gal (182,000 l; 40,030 imp gal), allowing for a 5,000-nautical-mile (9,300 km; 5,800 mi) range with a typical 452-passenger payload, and an increased MTOW of 750,000 lb (340,000 kg) was offered. The first -100B order, one aircraft for Iran Air, was announced on June 1, 1978. This aircraft first flew on June 20, 1979, received FAA certification on August 1, 1979, and was delivered the next day. Nine -100Bs were built, one for Iran Air and eight for Saudi Arabian Airlines. Unlike the original -100, the -100B was offered with Pratt & Whitney JT9D-7A, General Electric CF6-50, or Rolls-Royce RB211-524 engines. However, only RB211-524 (Saudia) and JT9D-7A (Iran Air) engines were ordered. The last 747-100B, EP-IAM was retired by Iran Air in 2014, the last commercial operator of the 747-100 and -100B.
