What is meant by the center of gravity range?

• A. The distance in inches between the forward allowable center of gravity and the rear-ward allowable center of gravity.
• B. The loss of stability at high speed.
• C. The maximum allowable forward CG position.
• D. The maximum allowable CG displacement.

Answer: (A)

The center of gravity range describes the span of positions the aircraft’s CG can occupy along the longitudinal axis while staying within safe stability and control margins. It’s defined by the forward and aft allowable CG limits.

The best answer reflects that range as the distance, in inches, between the forward allowable center of gravity and the rear-ward allowable center of gravity. This spread shows how far the CG can move in either direction from the datum before performance becomes unsafe or uncontrollable. For example, if the forward limit is at a certain inch mark and the aft limit is at another, the range is the difference between those two positions, measured in inches.

Why the other descriptions aren’t correct: instability at high speed is about aerodynamic stability, not how the CG is allowed to move within its range; focusing on a single limit (the maximum forward CG) only describes one end of the range, not the whole span; and a vague “maximum allowable CG displacement” doesn’t capture that the range is specifically the distance between two defined limits.