InterConnect deals with many different armed services all over the world. All of them are regimented, disciplined, and professional. Although there are many phrases in common for each of them throughout the world, one that stands out is “Bottom Line Up-Front” or BLUF. When commanders get briefed by others, they want BLUF or “What is the bottom line?” The BLUF to this blog’s question “How many flight control wiring harnesses are there in an F-16?” is 32 for a Block 15, one-seat F-16.
The F-16 is one of the first “fly by wire” aircraft in the world. Instead of cables and pulleys, the aircraft is controlled by electrical signals. The electrical signals tell the flight control surfaces how to move and how fast to move. There are 5 flight control surfaces on the F-16: (1) leading edge flap, (2) trailing edge flaps (also called flaperons), (3) horizontal tail (also called a taileron), (4) rudder (also called a vertical tail), and (5) speed brakes. Each of these structures move during flight and thus control the F-16. Actuators are attached to the light control surfaces to move them in flight. Actuators receive electrical signals (instead of cables and pulleys). The electrical signals are sent from computers (and the pilot) via electrical wiring harnesses. Thus, the wiring harnesses are important and play a huge role in the safety of the aircraft. The wiring harnesses that contain these electrical signals are called “Flight Control Wiring Harnesses”. When working on the F-16, maintainers can easily see which wiring harnesses are flight control because they have a double white tracer in the olive-drab Nomex braid. Figures 1 and 2 show a “non-flight control” and a “flight control” wiring harness, respectively.
Figure 1: Non-flight Control
Figure 2: Flight Control
Flight control wiring harnesses are installed throughout the F-16. Table 1 shows where they are generally located throughout the aircraft. The F-16 was designed with quadruple redundancy of its flight control systems. The four flight control systems are identified as A, B, C, and D. Each system sends and receives signals to computers that compare inputs and decides how to maneuver the aircraft. There are separate wiring harnesses for each of the four redundant systems throughout the aircraft. Additionally, each flight control wiring harness is installed away from the other flight control wiring harnesses to make sure that if one experiences a problem (such as bullets from small arms fire), then it will not affect the other flight control wiring harnesses.
Table 1: F-16 Flight Control Wiring Harness Locations
InterConnect recommends to replace flight control wiring harnesses at least every twenty years after installation. Early version F-16’s had Kapton insulated wires. Kapton insulated wires have potential problems after they get old and brittle. The only solution to this problem is to replace the old wiring harnesses with new ones. The flight control wiring harnesses in the forward bay and cockpit are replaced during large avionics upgrade programs such as Mid Life Update (MLU). The other flight control wiring harnesses are a different matter. They should be replaced at least every twenty years to avoid future problems. This is called “Preventative Maintenance”. InterConnect offers a flight control wiring harness replacement program (also called a rewire) for F-16’s throughout the world. For more information about our F-16 rewire programs please let us know
