The Boeing 747-400 is a wide-body airliner produced by Boeing Commercial Airplanes, an advanced variant of the initial Boeing 747. The “Advanced Series 300” was announced at the September 1984 Farnborough Airshow, targeting a 10% cost reduction with more efficient engines and 1,000 nmi (1,850 km) more range. Northwest Airlines (NWA) became the first customer with an order for 10 aircraft on October 22, 1985. The first 747-400 was rolled out on January 26, 1988 and made its maiden flight on April 29, 1988. Type certification was received on January 9, 1989, and it entered service with NWA on February 9, 1989.
The -400 was offered in passenger (-400), freighter (-400F), combi (-400M), domestic (-400D), extended range passenger (-400ER), and extended range freighter (-400ERF) versions. Passenger versions retain the same upper deck as the -300, while the freighter version does not have an extended upper deck. The 747-400D was built for short-range operations with maximum seating for 624. Winglets were not included, but they can be retrofitted. Cruising speed is up to Mach 0.855 on different versions of the 747-400.