A high-power HF radio operation may cause which of the following effects on the aircraft systems?

• A. Electromagnetic interference
• B. Improved navigation accuracy
• C. Increased engine performance
• D. Reduced avionics loading

Answer: (A)

High-power HF radio energy can couple into aircraft electrical and avionics systems, causing electromagnetic interference. The RF energy from powerful HF transmissions can travel along wiring, antennas, and other conductive paths, and radiate into nearby systems. This interference may show up as garbled or incorrect instrument indications, degraded navigation or communication performance, nuisance alarms, or autopilot instability. The airframe and avionics are designed to minimize this risk with shielding, filtering, proper grounding, and careful cable routing, but the potential for EMI remains a real consideration during high-power HF operations.

Therefore, the effect you’d most expect is electromagnetic interference with onboard systems. The other options describe positive or unrelated outcomes (improved navigation accuracy, increased engine performance, reduced avionics loading) that HF power does not produce.