Attrition: An F-22 Brought Down By A Hot Wire


August 20, 2013: The U.S. Air Force recently released the accident report for an F-22 that crashed last November during a training flight in Florida. The cause of that accident turned out to be a high power electrical wire that was worn and in contact with a hydraulic line. The charged wire eventually caused a hydraulic leak that the aircraft sensors detected, which shut down the hydraulic system in flight. The pilot attempted to restart the hydraulic system and that led to electrical sparks that ignited the leaked hydraulic fluid. Before that could be extinguished (by the fire suppression system) damage was done to the flight control system and that made the aircraft uncontrollable and the pilot had to eject. The entire F-22 fleet was then inspected for any similar electrical wiring situations and to make sure electrical wires are kept away from hydraulic lines.

This was the fifth F-22 fighter lost in an accident. Two of the crash losses were during testing. In three of the crashes the pilot survived. The first crash occurred in 1992, destroying the first YF-22 prototype. The first production F-22 lost was in 2004. That was followed in 2009, by the loss of an F-22 during a test flight. Another was lost in 2010, during a training flight.

Each of these losses has made a serious dent in the F-22 fleet. The 187th, and last, F-22 fighter was completed on December 13th 2011. This last aircraft was sent to a squadron in Alaska which lost one in an accident in 2010. The manufacturer is not going to scrap or sell off the tools and equipment used to produce the F-22 but will store the stuff for a while in the hope that production may resume eventually. There were also eight development prototypes built, for a total of 195 F-22s. With the five crashes, that leaves 190, but most of the remaining prototype aircraft are out of service. Currently 182 production aircraft are in service with 15 squadrons (three of them for training).

With the recent accident, the F-22 accident rate is a little over 6 per 100,000 hours. Note that the accident rate refers to any incident that costs more than two million dollars to repair, not just total loss of aircraft. F-15s and F-16s have an accident rate of 3-4 per 100,000 flight hours. India, using mostly Russian aircraft, has an accident rate of 6-7 per 100,000 hours flown (compared to 4-5 for all NATO air forces). The Indian rate had been over ten for many years and it is still that high and often higher. This is common with nations (including Russia and China) that use Russian aircraft designs. The B-52 has the lowest accident rate (less than 1.5 per 100,000 flying hours) of all American heavy bombers. The B-1s rate is 3.48. Compared to the supersonic B-1 and high-tech B-2, the B-52 is a flying truck. Thus the B-52, despite its age, was the cheapest, safest, and most reliable way to deliver smart bombs.

New aircraft always have higher accident rates, which is how many hidden (from the design engineers and test pilots) flaws and technical problems are discovered. The F-22 is expected to eventually have an accident rate of 2-3 per 100,000 flight hours.

Combat aircraft are becoming more reliable, even as they become more complex. For example, in the early 1950s, the F-89 fighter had 383 accidents per 100,000 flying hours. A decade later the rate was in the 20s for a new generation of aircraft. At the time the F-4, which served into the 1990s, had a rate of under 5 per 100,000 hours. Combat aircraft have gotten more reliable and easier to maintain, despite growing complexity, for the same reason automobiles have. Better engineering and more sensors built into the equipment makes it easier for the user and maintenance personnel to detect potential problems. Aircraft used the computerized maintenance systems, currently common on new aircraft, long before automobiles got them. Unless you have a much older car that still runs, or a real good memory, you don't notice the enormous increase in automobile reliability. But older pilots remember because such changes are a matter of life and death if you make your living driving an aircraft. And commanders know that safer aircraft gives you more aircraft to use in combat and more aircraft that can survive combat damage and keep fighting.




Help Keep Us From Drying Up

We need your help! Our subscription base has slowly been dwindling.

Each month we count on your contributions. You can support us in the following ways:

  1. Make sure you spread the word about us. Two ways to do that are to like us on Facebook and follow us on Twitter.
  2. Subscribe to our daily newsletter. We’ll send the news to your email box, and you don’t have to come to the site unless you want to read columns or see photos.
  3. You can contribute to the health of StrategyPage.
Subscribe   Contribute   Close