[1] This was intended as a highly fuel-efficient aircraft employing new technologies, but it was postponed indefinitely as the price of oil dropped during the 1980s.
[4] Japan initially agreed to a Letter of Understanding with Boeing in March 1984 to take a 25-percent share in a future 150-seat airliner, such as Boeing's Seven Dash Seven or Japan's "YXX" project, that would enter service in 1988 using the IAE V2500 turbofan as the engine,[5] which was developed in part by the Japanese Aero Engine Corporation.
However, Boeing became increasingly interested in the latest propfan engine research that would yield large double-digit fuel savings, in particular with the gearless unducted fan (UDF) concept from the aviation division of General Electric.
[7] It also scrapped the 7–7 code name, saying that the moniker was too commonly seen as a possible direct competitor to the Airbus A320, and that the aircraft Boeing had in mind would be a half-generation ahead.
[13] Shorts from the United Kingdom and Saab-Scania from Sweden also invested in the program a few weeks later, but with smaller, single-digit percentages.
The airline also expressed its desire to eliminate middle seats in a six-abreast configuration and asked that the cabin include a seven-abreast option for economy travel.
[18] The next month at the Farnborough Air Show, Boeing stated that the early acoustical results were better than expected.
[23][24] Boeing recommitted to the aft-mounted UDF in April,[25] albeit one day after IAE announced that it could not complete the engine by its previous May 1992 target date.
[27] Potential customers, who could afford to be choosier in an oversupplied world aircraft market,[28] were concerned about the economics and noise of the unproven propfan engines, though.
[29] Boeing neglected to survey the needs of different airlines before visiting them on a road show, so it was surprised by the unenthusiastic overall response to the 7J7 after the airframer had put so many resources into development.
[35] Later that month, Boeing pushed back the scheduled certification of the 7J7 from 1992 to 1993,[36] saying that the market needed time to decide whether it wanted a 140-seat or a 170-seat airplane.
[45] Two months later, Boeing confirmed that it was still meeting with its Japanese partners twice a year to discuss the 7J7, which was now framed as an eventual replacement for the 737.
[46] Boeing chairman Frank Shrontz renewed the joint 7J7 development agreement with the Japanese firms in Hawaii, and planned to modify their memorandum of understanding.
[49] However, Alan Mulally, who was director of engineering for the 7J7 and would become the CEO of Ford Motor Company two decades later, stated that the 7J7 was one of the best research and development investments that Boeing ever made.
[56] The airframer hoped to build the 7J7's wings out of aluminum-lithium, despite the material costing about three times more to use than conventional aluminum alloys.
[63] The twin-aisle setup would reduce passenger onboarding and deboarding times by ten minutes,[64] allowing airlines to plan for 50-percent faster turnaround times compared to its competitors;[31] Boeing's research found that even two 18-inch skinny aisles (46 cm) turned passengers around faster than one 26-inch wide aisle (66 cm).
[66] Boeing also provided a higher gross weight option for the plane by configuring the in-fuselage part of the wing to hold fuel.
[70] It could be used for bulk storage or to hold standard LD3-46 unit load devices, a smaller size of air cargo container that was entering usage with the debut of the Airbus 320.