The C-17's wing 'failed' its test, until engineers rechecked the loading
In 1992 the C-17 Globemaster III's wing buckled at 128 percent of its design limit, short of the 150 percent target, and about $100 million went into a redesign. A second test failed at 145 percent. Then a review found the wing had been loaded wrongly all along and actually met the requirement.
The big airlifter began as a stretched, swept-wing descendant of the YC-15, a smaller prototype McDonnell Douglas built in the 1970s for an Air Force contest that was cancelled before any winner emerged. When the Air Force launched its C-X programme in 1979, it needed something to replace an ageing fleet of C-141 Starlifters and to take some pressure off the giant C-5 Galaxy. McDonnell Douglas beat bids from Boeing and Lockheed on 28 August 1981.
Development dragged. Budget limits pushed the schedule back four years, and in April 1990 Defense Secretary Dick Cheney cut the planned order from 210 aircraft to 120. The first flight, from Long Beach on 15 September 1991, came roughly a year late. In late 1993 the Pentagon gave the contractor two years to fix production and cost problems or lose the deal after the 40th plane, and accepting those terms cost McDonnell Douglas nearly $1.5 billion.
Watchdog reports were sceptical. A 1994 Government Accountability Office review noted that earlier studies claiming the C-17 could use 6,400 more foreign runways than the C-5 had looked only at runway size; once pavement strength was factored in, the advantage shrank to 911 airfields. Another found that a fully loaded C-17 could not land on a wet 3,000-foot runway. Yet by September 1995 most problems were reportedly solved, and the aircraft entered service that year.
Orders then grew steadily, especially after Boeing absorbed McDonnell Douglas in 1997, and the last airframe left Long Beach in November 2015. The C-17 carries troops, cargo and casualties, and airdrops supplies. It flew key logistics during the wars in Afghanistan and Iraq, delivered aid after the 2010 Haiti earthquake, and serves air forces from India and Britain to Qatar and Canada.
Source: Boeing C-17 Globemaster III
