Definition
A secondary source of electrical power, independent of the main electrical system, that supplies a FADEC-equipped engine if the aircraft's primary electrical system fails. Because a FADEC engine relies entirely on electronic control, the engine cannot run without electrical power, so a dedicated backup source — typically a separate alternator, battery, or permanent magnet generator on the engine itself — is required to keep the FADEC operating.
Plain English
A second, separate way to keep electricity flowing to the engine's computer if the main electrical system quits. Without it, a FADEC engine would stop running.
Context Anchor
Seen in discussions of FADEC engines, electrical system reliability, and emergency planning for loss of normal electrical power.
Why Pilots Care
Maintains continuous engine control and prevents uncommanded shutdown during primary power loss.
Grounding Statement
If the main electrical supply fails in flight, the backup electrical source is the power path that may keep the engine control working.
Intuition Check
Backup does not mean extra power for normal use. Here it means an alternate power supply available to take over if the normal supply fails.
Example Sentence 1
Because the aircraft uses a FADEC, it has a backup electrical source that automatically takes over if the main alternator fails.
Example Sentence 2
During preflight, the pilot confirmed that the backup electrical source was charged and ready.