The 747 ASB

Boeing announced the 747 ASB — Advanced Short Body — in 1986, as a response to two aircraft then in development: the Airbus A340 and the McDonnell Douglas MD-11.

The idea

Both competitors were aimed at long, thin routes — journeys long enough to need range, but with too few passengers to fill a full-size 747. Boeing’s proposal was to shorten the 747’s fuselage while keeping the technology being developed for the 747-400: the new wing with winglets, the two-crew glass cockpit, and the improved engines.

The result would have been an aircraft with 747 range and systems, sized closer to its rivals.

Why it did not happen

The ASB ran into the same arithmetic that had limited the 747SP a decade earlier.

Shortening a 747 does not reduce its costs proportionally. The wing, the undercarriage, the four engines and much of the systems weight stay broadly the same, because they are sized for the wing and the mission rather than the cabin. Take away fuselage and you remove revenue seats while keeping most of the expense — so cost per seat rises sharply.

That was exactly why only 45 747SPs were built. Airlines could see the same problem in the ASB, and the interest Boeing needed did not materialise.

What Boeing did instead

The effort went into the 747-400, which became the best-selling 747 of all, and then into a genuinely new aircraft for that market segment: the 777, a twin-engined widebody designed from the outset for long, thin routes.

The 777 succeeded precisely where the ASB would have struggled, because two engines and a purpose-sized airframe beat four engines and a truncated one. In hindsight the ASB’s failure to launch looks less like a missed opportunity than an early signal of where the market was going.