At Pinal Airpark, in the desert north of Tucson, the airplanes sit in rows the way old men sit in rows at a clinic, waiting for something that isn’t coming. A great many of them are 747s, parked here because the engines are worth more than the rest of the airframe and somebody, someday, may want the engines. Somewhere among the rows is one that’s shorter than its neighbors by nearly fifty feet, the line of its fuselage interrupted just behind the wing as though a piece had been folded in and stitched shut. This is a 747SP, and there were only forty-five of them ever built, because the airplane was, from the moment it was conceived, a compromise built to solve one problem and no other.
The problem belonged to Pan American World Airways. In the early seventies Pan Am wanted to fly nonstop from New York to Tehran, a route that did not then exist because no airliner Pan Am owned could cover the distance with a full load of passengers and still land with fuel in the tanks. Iran Air had the identical problem in reverse. Boeing had, at the time, the 747-100, an airplane that could carry nearly everybody in the world somewhere, but not necessarily that far. McDonnell Douglas and Lockheed had the DC-10 and the L-1011, three-engine widebodies built expressly for the medium-haul market the 747 was too big to serve efficiently, and Boeing, watching two competitors carve into territory it had assumed it owned outright, needed an answer that did not require designing a new airplane from the keel up. There was no time and, after the financial near-catastrophe of developing the original 747, no appetite for one.
The man who supplied the answer was Joe Sutter, the engineer who had led the 747 program from the start and who brought to it an instinct for solving problems by subtraction. Sutter’s idea was not to add a third engine, which several engineers in the room had assumed was the path, since removing one engine entirely was reckoned to save a third of the fuel burn and nearly seven tons of weight in one move. Sutter’s idea was to leave the engines alone and shorten the airplane instead. Take fuselage out fore and aft of the wing, forty-eight feet four inches of it, lighten the structure to match, simplify the flaps from the standard triple-slotted design to a single-slotted one, lengthen the tail surfaces to keep the shorter airplane stable, and let the weight savings buy range instead of payload. Boeing’s engineers called the result, informally and a little affectionately, Sutter’s Balloon. The company filed it as the 747SB, for Short Body, before settling on a name that did the marketing for itself: 747SP, for Special Performance.
The first one, manufacturer’s serial number 21022, rolled out of the Everett plant on May 19, 1975, and flew on July 4th, ten days ahead of a schedule that was already tight. Jack Waddell, who had flown the maiden flight of the original 747 six years earlier, was in the left seat again, and on that first flight he put the shortened airplane through a stall and a run up to Mach 0.92, a speed that had no business being associated with anything called a jumbo jet. In November, Boeing flew the fourth airframe nonstop from New York to Tokyo, 6,927 miles, with two hundred passengers aboard, and landed in Seattle’s backyard with more than thirty thousand pounds of fuel still in the wings, a fact Boeing’s marketing department repeated for years the way a man repeats the one good thing a difficult relative once said about him. The FAA signed off in February of 1976. Pan Am took delivery of the first production airplane, named Clipper Freedom, on March 5th, and put it into revenue service in April.
What the SP was for, it did well. A South African Airways SP flew nonstop from the Boeing plant in Seattle to Cape Town on its delivery flight in 1976, a record for an unrefueled commercial airplane that stood for more than a decade. Pan Am flew SPs around the world in well-publicized record attempts, and for thirteen years, until the 747-400 arrived in 1989, the SP held the title of longest-range airliner in the world. It is a title that means something only to the small number of people who keep track of such titles. Boeing had once projected sales in the neighborhood of two hundred. Fuel prices rose through the back half of the seventies and into the eighties, and the SP, despite its range, cost more to fly per seat than the standard 747 it had been built to outdo on a narrower set of routes. Twin-engine widebodies were coming that would solve the same range problem with half the engines to maintain. Production ran from 1976 to 1982, paused, and then opened once more in 1987 for a single VIP-configured order from the Abu Dhabi Amiri Flight, after which Boeing closed the line for good. Forty-five airplanes, full stop.
A handful of them found second careers that outlasted anything the airline business had planned for them. One, a former Pan Am airframe, was hollowed out by NASA and the German Aerospace Center and fitted with a hatch that opened in flight to expose a reflecting telescope two and a half meters across, an arrangement that let astronomers fly above most of the water vapor in the atmosphere and look at the sky the way the ground never quite allows. It flew as the Stratospheric Observatory for Infrared Astronomy until 2022. As of this year, the airplanes still capable of flight number three: two belong to Pratt & Whitney Canada, which uses them as flying engine test beds, bolting experimental turbines onto a wing built half a century ago to prove an idea about subtraction; the third belongs to a casino company in Las Vegas, configured for fifty passengers, which is roughly the inverse of what Joe Sutter had in mind. The rest are scattered in places like Pinal Airpark, sitting in rows, shorter than their neighbors, waiting on engines somebody might still want.
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