A Quick History of Concurrency

May 21, 2013 No Comments by

I really enjoy your magazine entirely. As I read the latest issue (June 2013), I found myself disagreeing with one statement made by Robert Dorr on his article “A Troubled Bird” about the F-35. On p. 34, in discussing the supposed “concurrency” of the F-35 program, he says “concurrency … (is where) … the aircraft is being tested and placed into service simultaneously. It has never been tried on this scale before.” Concurrency was common in Cold War fighter development programs. For example, the F-15 development contract was let in December 1969, with an associated production lot buy of 20 aircraft (today we would call these Low Rate Initial Production deliveries). The F-15 had a new airframe capable of Mach 2.5 speeds, powered by two new Pratt & Whitney engines giving the aircraft a better than 1 to 1 thrust-to- weight ratio, with an all new avionics suite. There was no prior prototype program. The F-15 flew in 30 months, and reached initial operational capability with the 20 production aircraft delivered forming the first squadron in just over five years … in 1975. By then, it has also completed most of the development program. The F/A-18A/B Hornet has a similar development and production concurrency plan, albeit the basis of redesigned Hornet was Northrop’s YF-17 prototype aircraft which lost the competition to General Dynamics YF-16 to become the USAF’s low-end fighter. Today’s programs, such as the F-22 and F-35, were supposed to benefit from risk reduction in big, expensive prototype fly-off competitions that haven’t seemed to payoff in eliminating technical problems, cost overruns, and schedule delays. And, if anything, these delays and the lack of concurrency in production has contributed to cost growth and obsolescence problems before the aircraft is actually fielded.

Ed Will, St. Charles, MO
McDonnell Douglas/Boeing retired

Good insights, Ed. — BD

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Budd Davisson is the Editor-in-Chief of Flight Journal. Since 1996, Flight Journal has been the undisputed leader in the field of aviation photojournalism and presented aviation history through the eyes of those who made it.
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