One of the most unusual widebody aircraft to take to the skies, the Boeing 747SP has the distinction of the shortest production run of any Boeing jetliner. Boeing built only 45 of them between 1975 and 1987. But the 747SP was far from a folly. Instead, it was the innovative result of two different market forces at play at the time of its launch in September 1973.
One of those forces was the development and launch was the arrival of the Lockheed L-1011 Tristar and McDonnell Douglas DC-10 after the Boeing 747 was already in production. The widebody trijets were dominating the market space between the 169-seat Boeing 707 and the 380-seat Boeing 747. At the time of their respective launches, the DC-10 and Tristar did not have the range of the 747, but it was well known that both McDonnell Douglas and Lockheed were working on longer range derivatives of their aircraft.
The 747SP was a solution to a problem: build a competitor to the DC-10 and L-1011 that could beat them on range. A shortened derivative of the 747-100/200, development costs were minimized. The SP could be put into production quickly and provided commonality to operators who already had the 747-100/200 in service.
After rejecting a three-engined design for the 747SP on the basis of development costs, the program took on added urgency when a second market force entered the picture: Pan Am indicated that it had a requirement for a long range aircraft that could serve routes like New York-Tehran or any other destination in the Middle East. With McDonnell Douglas and Lockheed announcing long range versions of their aircraft to meet the Pan Am requirement, things moved quickly at Boeing. Experience had shown that what Pan Am wanted had market appeal. Pan Am would be the 747SP’s launch customer, announcing its orders a month after the program launch in September 1973.
Though essentially a shortened 747, the SP had a new fuselage section aft of the wing, a taller vertical fin with a double-hinged rudder to compensate for a shorter moment arm, reduced gauge spars, skin, and ribs in the wings and simple single slotted flaps.
The first 747SP rolled out on 19 May 1975, ten days ahead of the schedule laid down at program launch. It gained its type certificate on 4 February 1976, seven months after its maiden flight. The first SP was delivered to Pan Am as Clipper Freedom (N533PA) on 5 March 1976.
Despite the performance of the 747SP, it wasn’t the success Boeing planned. Most of this was simply a function of the incremental improvements in the 747-200 which narrowed the performance gap between the 747SP and the 747-200B in particular. In addition, the DC-10 and L-1011 Tristar each had one less engine than the 747SP, and therefore a lower fuel burn. The last SP was delivered in 1989 to the government of the United Arab Emirates as a VIP transport.
The arrival of 747-400 and the 777 – as well as the Airbus A330/340 – led to the progressive phase out of the small worldwide 747SP fleet. The aircraft was best suited to long, thin routes but at the time of the SP’s introduction, the passenger demand simply wasn’t as great. It remains a fascinating expression of engineering and rapid market response at a time when passenger numbers were on the cusp of a massive increase worldwide.