During the Cold War when the West was concerned about the Soviet Union’s undersea fleet, McDonnell Douglas Corporation (MDC), which later merged with Boeing, offered the U.S. Navy an anti-submarine patrol aircraft under the Long-Range Air ASW Capable Aircraft (LRAACA) program that looked like a familiar jet airliner – but, then again, it didn’t.

The November 1986 design resembled a DC-9, which was known to its builder as the MD-87 and to the Navy as the C-9B Skytrain II, but it was powered by two ultra-high bypass (UHB), unducted fan engines driving what appeared to be twin pusher propellers at the rear of the fuselage.

MDC said it could complete the first flight of its “Advanced USN Patrol Aircraft” in 1990 and deliver combat-ready planes to the Navy by late 1991.

MDC’s Advanced USN Patrol Aircraft retained the fuselage, wings, and landing gear of the DC-9, which was a proven commodity to aviators and maintainers in the Fleet, but introduced the new engine concept. The UHB powerplants were meant to improve fuel economy – just what the Navy needed for grueling, long-range patrols stalking Soviet submarines. To the untrained observer, the UHB looked like a propeller engine, since it employed unducted blades for a portion of its thrust. In fact, it was a type of jet engine.

The first Reagan administration was about to be followed by the second. The Soviet threat loomed, and defense spending was bountiful. The Navy placed high priority on getting a new, advanced aircraft to replace the four-turboprop Lockheed P-3 Orion.

The Navy was very serious in wanting a P-3 Orion replacement. Great Britain and West Germany also wanted a new maritime patrol aircraft. The MDC proposal was a response to a Navy program called LRAACA (Long-Range Air ASW Capable Aircraft). Boeing and Lockheed submitted their own proposals under the program. The winning planemaker would build 125 LRAACAs for the Navy and a dozen each for Britain and Germany.

MDC’s Advanced USN Patrol Aircraft retained the fuselage, wings, and landing gear of the DC-9, which was a proven commodity to aviators and maintainers in the Fleet, but introduced the new engine concept. The UHB powerplants were meant to improve fuel economy – just what the Navy needed for grueling, long-range patrols stalking Soviet submarines. To the untrained observer, the UHB looked like a propeller engine, since it employed unducted blades for a portion of its thrust. In fact, it was a type of jet engine.

Under a program sponsored by NASA, one type of UHB engine was being test flown aboard a Boeing 727 test aircraft. This was the General Electric Unducted Fan Demonstrator Engine. A different UHB engine, the Pratt & Whitney/Allison 578 DX, was being developed but had not yet flown. MDC was prepared to offer the Advanced USN Patrol Aircraft with either powerplant. Experts claimed the plane would have had a 48 percent lower fuel burn than the Orion when flying a typical maritime patrol.

Except for its unorthodox source of power, the aircraft would have looked remarkably like short-body DC-9 airliners then plying the nation’s airways, but its 130-foot fuselage would have been ten feet longer.

Its interior fuselage would have been fitted with P-3C Update III anti-submarine sensors, and the aircraft would have carried radar, AGM-84 Harpoon missiles, torpedoes, mines, sonobuoys, and a mission control center with up to half a dozen technicians. Total crew would have been eleven.

Without building or flying any of the competing designs, the Navy ultimately chose Lockheed’s candidate, the P-7A, a new aircraft which looked much like the P-3 Orion but offered new engines, propellers, and other features. The choice of the P-7A ended plans for the unique MDC airplane, but the P-7A, too, proved to be a dead end. The P-7A effort ran into technical and fiscal difficulties, and on July 20, 1990, the Navy terminated the program. Britain and Germany then went their own way in developing maritime patrol planes.

By then, the Berlin Wall had fallen, the Cold War had ended, defense spending was down, and there was less impetus for an Orion replacement. In more recent years, the Navy began acquiring the P-8A Poseidon, a version of the Boeing 737.