Definition 1 of 2
Definition
A type of computer memory that retains its stored data when electrical power is removed. Used in avionics for storing information that must survive power-down, such as navigation databases, configuration settings, fault logs, and engine monitoring records.
Plain English
Memory that keeps what it has stored even after the power is turned off.
Context Anchor
Seen in avionics, engine monitors, navigation equipment, and other aircraft systems that must retain settings, fault records, or stored data after shutdown.
Derivation
Volatile comes from the Latin volare, meaning 'to fly.' A volatile substance flies away easily. Volatile memory loses its contents the moment power is cut. Nonvolatile memory does not 'fly away' when the power goes off.
Why Pilots Care
It keeps navigation databases, fault logs, and operating software intact across every power cycle, supporting reliable system restarts and post-flight data retrieval.
Analogy
It is like writing a note on paper instead of saying it out loud. If the room goes dark, the written note is still there when the lights come back on.
Intuition Check
Nonvolatile does not mean the memory can never be damaged or erased. It means the stored information normally remains there without electrical power.
Example Sentence 1
The engine monitor stores exceedance events in nonvolatile memory, so the data is still available the next morning when the mechanic plugs in.
Example Sentence 2
Maintenance crews read the nonvolatile memory in the engine control unit to review fault codes recorded on previous flights.