Many readers probably do not know what the term Mean Time Between Failure (MTBF) means. MTBF is a measurement of the number of days (or years) that a device will fail based on test results or past performance. In the aerospace industry, MTBF is calculated for just about every piece of equipment that has active mechanical or electrical components. In theory, MTBF is a preventative action tool where a piece of equipment is replaced or overhauled before it fails. Commercial airlines as well as Original Equipment Manufacturers (OEMs) like Lockheed Martin, Boeing, and Airbus spend millions of dollars developing and refining MTBF’s for just about everything on an aircraft. This holds true for military aircraft including the F-16.
Here is an example of how MTBF is used in the aerospace industry. Let’s say Lockheed Martin is designing a new aircraft. As part of the design, Lockheed hires another company to design a new hydraulic pump. Included in the design-work, the company is also responsible for setting an initial MTBF. The company can do this task based-on previous performance of other similar hydraulic pumps, or they cycle (or age it) repeatedly before it fails. Let’s say the MTBF for this pump is 1,200 hours. Once this baseline is established, the owners of the aircraft know that they need to remove and replace (and/or overhaul) this pump before 1,200 hours. After MTBF is established for a piece of equipment, effort is made to determine ways to improve the design of the pump to increase its MTBF. If the cost to improve the design is less than the cost of replacing/overhauling the pump, the user of the aircraft saves money.
Any guess what the MTBF is for F-16 wiring harnesses? Look at the table below and guess the number of days an F-16 wiring harness will last.
How many days did you guess? That is, when will an F-16 wiring harness fail? If you guessed none of the above then you are correct. The correct answer is infinity or said in a different way, there is no MTBF for F-16 wiring harnesses. It is assumed that once you install a wiring harness inside an F-16, it will never fail. It will continue to work as designed until the aircraft is done and sent to the scrapyard or graveyard. One interesting point to mention is that although many F-16’s were retired and sent to the graveyard (or boneyard), they are now being taken out of the boneyard for refurbishment. Bulkheads and other structures are replaced to extend the lifetime of the aircraft but there is little thought about replacing the old wiring harnesses. Isn’t that crazy for aircraft over 20 years old???!!!
What’s even crazier is that the MTBF of wiring harnesses of new aircraft such as the F-35 is also infinity. There is no planning or preventive maintenance for wiring harnesses even on a 5th generation fighter!
InterConnect prides itself on being the world’s leader in F-16 wiring harnesses and F-16 electrical panel assemblies. After 25+ years of extensive research, we have recommendations on what the MTBF should be for F-16 wiring harnesses. Before providing our F-16 wiring harness MTBF recommendation, InterConnect must first release two more informative blogs to pave the way. The first blog deals with something called “inherent viscosity”. The second blog answers this question, “Why is MTBF not determined for most aircraft electrical wiring harnesses?” After these two blogs are released, InterConnect will provide our recommendation for the MTBF of F-16 wiring harnesses.
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