Definition
Permanent weight installed in an aircraft at a specific location to bring its center of gravity within allowable limits or to correct an out-of-balance condition. Fixed ballast is secured to the structure and is not removed during normal operations. Its installation must be approved and recorded in the aircraft's weight and balance records.
Plain English
Extra weight bolted into the aircraft to make it balance correctly. Once it is installed, it stays there — the pilot does not add or remove it for each flight.
Context Anchor
Seen in weight-and-balance discussions, aircraft records, and maintenance entries when an aircraft needs added weight to balance correctly.
Derivation
Ballast comes from an old Scandinavian word for the heavy material — sand, stone, or iron — placed low in a ship's hull to keep it stable. The same idea carries into aviation: weight added to keep the aircraft balanced. 'Fixed' here means permanently installed, not adjustable flight to flight.
Why Pilots Care
Keeps the center of gravity within certified limits for all normal loading conditions, directly affecting stability, control feel, and safe flight characteristics.
Intuition Check
Fixed does not mean “repaired” here; it means fastened in place. Ballast is not useful cargo—it is weight carried for balance.
Example Sentence 1
After the avionics upgrade moved equipment forward, the mechanic installed fixed ballast in the tail to bring the center of gravity back within limits.
Example Sentence 2
Because the aircraft carried fixed ballast, the pilot did not need to add temporary weights when flying with a light passenger load.