Which statement best describes how the CG is affected when a weight located aft of CG is removed?

• A. Forward in proportion to weight and location.
• B. Backward in proportion to weight and location.
• C. No change.
• D. Upward.

Answer: (A)

The center of gravity is the weighted average of all weights’ locations. If you remove a weight that is behind the CG, you reduce the aft moment more than you reduce the front moment, so the overall balance shifts toward the nose. In math terms, removing a weight located aft of the CG changes the CG to a new position that is forward of the original, with the amount of shift increasing with both the removed weight and how far aft it was.

For example, if the airplane weighs 6000 lb with a CG at 2.0 ft, and you remove 1000 lb located at 3.0 ft, the new CG moves forward from 2.0 ft to about 1.8 ft. This illustrates that the forward shift is proportional to the weight removed and its distance aft of the CG.

If you removed weight forward of the CG, the CG would move backward toward the tail; removing weight exactly at the CG would leave the CG unchanged. Upward isn’t a relevant description for CG shift.