"On This Day" In Engineering History Blog

"On This Day" In Engineering History

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July 23, 1970 - The First McDonnell-Douglas DC-10

Posted July 23, 2008 9:40 AM by Steve Melito

On this day in engineering history, the first McDonnell-Douglas DC-10 emerged from the company's final-assembly hangar in Long Beach, California. The debut of this wide-bodied jet transport was witnessed by 1,000 guests, including representatives of the 15 airlines that had placed orders for an aircraft that McDonnell-Douglas hoped would compete with the Boeing 747, Lockheed L-1011, and Airbus A300. Tragically, however, the DC-10 may be best remembered for a series of well-publicized plane crashes during the 1970s.

Designing and Building the First DC-10

Registered as N10DC, the first McDonnell-Douglas DC-10 was the product of new design and manufacturing processes. In addition to wooden mockups, aircraft designers built a dimensionally accurate, full-scale metal model that included the fuselage, tail fin, and wing junction. According to Gunter Endes, author of the 1998 book McDonnell Douglas DC-10, this technique "allowed the accurate fitting of electrical wiring, piping, ducting, insulation blankets and other linings prior to production." During production, five-axis, numerically-controlled milling machines were used to produce large, machined parts. According to Endes, 70 of these machines ran 24 hours a day, six days a week.

Large Loads and Long Hauls

The McDonnell-Douglas DC-10 was designed to carry as many as 380 passengers on long-range routes up to 3,800 miles. With a top speed of 600 miles per hour (mph), the wide-bodied jet featured three General Electric (GE) turbofan engines. Two of these engines were mounted on underwing pylons while the third was mounted at the base of the vertical stabilizer. The original engine model, GE CF6-6D, provided 40,000 pounds of thrust (lbf). The final DC-10 variant, the DC-10-40, used Pratt and Whitney JT9D-59A engines with 53,000 lbf. Today, the U.S. Air Force uses a modified DC-10-30 as an air-to-air tanker. With a maximum fuel load of 356,000 lbs., the KC-10 Extender has been in active service since 1981.

Maintenance Matters: The Safety Record of the DC-10

Although the lifetime safety record of the DC-10 was comparable to those of other heavy passenger planes, the aircraft may be best remembered for its brief grounding by the U.S. Federal Aviation Administration (FAA) in the summer of 1979. On May 25th of that year, an American Airlines DC-10 (Flight 191) crashed shortly after take-off near Chicago when a pylon-mounted engine separated from the aircraft. After examining cracks in the wing pylons of other DC-10-10s, FAA inspectors determined that the cause of the Chicago crash was an improper maintenance procedure in which mechanics used a forklift to remove both the engine and the pylon. Critics of the DC-10 remained skeptical about the aircraft's design, however, and noted past problems with the plane's cargo doors and hydraulic system.








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