What is the smallest cable diameter permitted in primary control systems?

The smallest cable diameter permitted in primary control systems is one-eighth inch. This standard is established to ensure sufficient strength and durability in the control cables that are vital for aircraft operations. Cables that are too thin may not withstand the forces exerted during flight operations, potentially leading to failure in control surfaces and endangering flight safety.

Using a one-eighth inch diameter cable strikes a balance between providing adequate strength and minimizing weight, which is crucial in aviation design. This dimension is generally accepted across various regulations and practices to maintain the integrity and reliability of primary control systems. The specified diameter ensures that the cable can resist wear and fatigue over time while handling the necessary loads during operation, thus ensuring that pilots retain full control of the aircraft in all phases of flight.