When is a total aircraft rewire needed? Let’s take a step back and ask a more common question that military users and maintainers of aged aircraft ask: “When should any aircraft rewire program be considered?” Here are 5 Main Factors to contemplate when deciding to rewire a military or commercial aircraft. They are listed in the order of importance.
THE TYPE OF INSULATION OF THE WIRE
Surprisingly, the most important factor is the type of insulation of the wire in the aircraft. A wire that undergoes hydrolysis is more likely to become aged and brittle. Unfortunately, many of the older aircraft have polyimide insulation. Polyimide insulation is commonly known as Kapton™ and can tend to experience hydrolysis more than other aircraft insulation types.
ENVIRONMENT WHERE OPERATED
The environment is the second most important aspect when considering rewiring your fighter jet, fixed wing, or helicopter. An aircraft that has primarily operated in a wet, salty, and/or humid environment is more likely to need to be rewired much sooner than one that is operated in hot dry environment.
THE AGE OF THE AIRCRAFT
The third main factor is the age of the aircraft. Age is defined as the number of years since the aircraft has left the production line. Generally speaking (and depending on the type of insulation and the environment in which it operated) rewire should be considered once it is 20 years old. After 20 years, the cost benefit analysis shows it is more beneficial to rewire a fleet of aircraft than continue to fix wire-related problems.
NUMBER OF INTERMITTENT PROBLEMS EXPERIENCED OVER THE PAST YEAR
The fourth item to consider is the number of intermittent and wire-related problems that an aircraft experiences. Some aircraft seem to have more wire related problems than others. Typically, they either have a gremlin in them or were operated in a harsher environment than the other aircraft in the fleet. It is recommended that all intermittent problems be recorded and analyzed on a yearly basis. If this analysis is done over many years, trends will be apparent and justify a complete or partial rewire of the aircraft.
THE NUMBER OF FLIGHT HOURS
Finally, the last factor is the number of flight hours. Many people think the number of flight hours is the most important factor when in fact it is not. The other four factors above have more of an effect than flight hours on deciding when to rewire. Flight hours however is a factor and should be considered. An aircraft flown more than other aircraft tend to have more intermittent and wire-related problems than other aircraft.
InterConnect Wiring has done multiple studies analyzing older aircraft wiring. Click here for a copy of one of the original studies that InterConnect performed.
Now back to the original question… when is a TOTAL rewire needed? If your aircraft has experienced three or more of the five factors listed above, a total aircraft rewire is recommended.