* Since their advent in the 19th century, interchangeable parts have allowed manufacturers to efficiently produce products in quantity and for lower costs. And after a product leaves the manufacturer's assembly line, such parts make repairs significantly easier than handmade or custom-fitted parts ever allowed.
Interchangeable parts are undoubtedly a fundamental building block of success in industrial manufacturing.
But today, as mechanized products evolve into an element of a more integrated complex system, changing out a failing part for an identical interchangeable part may not be as straightforward as it has been in the past. In defense, especially, as state-of-the-art weapon systems advance to include architecture that exploits automated self-healing recovery and artificial intelligence, swapping out parts may no longer be possible without jeopardizing the delicate relationships among linked components and subsystems within the greater system.
For many years, perhaps decades now, maintenance crews realized that if they had two or more similar complex systems, say, frontline military aircraft, and more than one was down for different maintenance reasons, they could remove parts or components from one system to repair the others. In many situations, cannibalizing one system for its interchangeable parts enabled maintainers to return failed systems to working order more quickly than did troubleshooting and repairing individual problems or diving into inventory, finding the appropriate new part, and installing it.
The reasons for cannibalism are numerous. If a part had to be shipped from a depot, the original manufacturer or a subcontractor, the wait time could be excessive. Furthermore, if the user community had not paid for availability, the part may not be sitting on the manufacturer's shelf available for shipping. When budgets are reduced, such as with sequestration, parts availability is one area that is quickly underfunded. So, "living like a cannibal" evolved into a procedure of necessity for maintenance crews.
The consensus opinion is that underfunded spares may be the principal factor in this now well-established procedure of cannibalizing one aircraft to preserve readiness in others. The Government Accountability Office and other investigators have highlighted the possible causes and ill effects this practice creates.
Recent investigative reports in the news focus on readiness rates that are in some cases below 50 percent--a...