Avionics and Aircraft Systems Installation
Core concepts
Avionics installation begins with approved data: wiring diagrams, equipment location, power budget and weight-and-balance impact. Each LRU needs a proper rack or mount, correct connectors, keying and torque, plus enough cooling and vibration isolation. Power feeds should be protected by a breaker or fuse sized to protect the wire and carry the load; avionics often use a dedicated bus.
Grounding and bonding control noise and provide fault return. Use single-point grounding where specified, bond the airframe, and avoid ground loops. Shielded and twisted wires, separation from high-current cables, and careful coax routing reduce EMI. Antennas need a proper ground plane, a clear view and low-loss cable; check VSWR after installation.
Document the work, update the weight and balance, load the correct software and configuration, and perform functional and operational checks before return to service.
Traps
Questions test breaker sizing (protect the wire, not just the load), shield termination, antenna cable loss, connector torque, and whether power was removed before work. Do not assume a larger breaker is safer.
Worked example
An avionics package draws 8 A on a 28 V bus. Choose a breaker above the load but at or below the wire's ampacity - for example, a 10 A breaker with wire rated at least 10 A in the installed bundle - then verify voltage drop at the LRU connector.