Definition
A failure or abnormal operation of onboard radios, navigation receivers, or related avionics that prevents the pilot from communicating with air traffic control or navigating by the intended means. Such malfunctions trigger specific lost-communication and lost-navigation procedures defined by regulation and by the flight's clearance, allowing the pilot to continue and complete the flight safely under known rules.
Plain English
Something has gone wrong with the radios or navigation equipment, so the pilot can no longer talk to controllers or navigate the way they were planning to. There are set rules for what to do next so the flight can still finish safely.
Context Anchor
Encountered during instrument flying when a radio, navigation receiver, display, antenna, or related electrical equipment stops working normally or gives unreliable information.
Derivation
Communication comes from a Latin word meaning “to share” or “make common.” Navigation comes from Latin words connected with guiding a ship. Malfunction means “bad working.” Together, the phrase points to equipment that is not properly sharing information or helping guide the aircraft.
Why Pilots Care
Loss of these systems in IMC requires immediate use of backup procedures or diversion to maintain safety.
Grounding Statement
The key point is not that every device is dead; the key point is that a system the pilot depends on for talking or navigating is no longer trustworthy.
Intuition Check
Do not assume malfunction means complete failure. In aviation, a malfunction can also mean the equipment works only part of the time, gives wrong information, or cannot be trusted.
Example Sentence 1
After losing both radios in the clouds, the pilot recognized the communication/navigation system malfunction and continued the flight using the lost-communication procedures from the clearance.
Example Sentence 2
Training covers steps to take after a communication/navigation system malfunction to keep the flight safe.