What is meant by permanent ballast for an aircraft?

• A. Weight temporarily installed for testing.
• B. Weight that is permanently installed to bring the empty weight center of gravity into allowable limits.
• C. Extra fuel stored in fixed tanks.
• D. Weight used only during ground testing.

Answer: (B)

Ballast is fixed weight added to an aircraft to control its weight distribution, specifically to place the empty weight center of gravity within the approved range. Permanent ballast means this weight is installed so it stays with the aircraft for its life and is included in the empty-weight and moment data. It’s used to position the aircraft’s baseline CG so, as loads change (fuel, passengers, baggage), the CG remains within allowable limits for safe handling. This is different from weights used only for testing or ground checks, which are removed after use, and from fuel, which is consumed and changes the mass and moment during flight.