An empty aircraft has combined main gear weight 3540 lb at 195.5 in, nose gear weight 2322 lb at 83.5 in; datum is forward of the nose. What is the empty CG?

An empty aircraft has combined main gear weight 3540 lb at 195.5 in, nose gear weight 2322 lb at 83.5 in; datum is forward of the nose. What is the empty CG?

• A. 150.5 inches
• B. 151.1 inches
• C. 152.3 inches
• D. 149.0 inches

Answer: (B)

Finding the empty center of gravity uses moments about a reference datum. Multiply each weight by its distance from the datum (its arm), sum those moments, then divide by the total weight to get the CG position relative to the datum. Compute the moments: 3540 lb at 195.5 in gives 692,070 lb·in. The nose gear is 2322 lb at 83.5 in gives 193,887 lb·in. Total moment = 885,957 lb·in. Total empty weight = 3540 + 2322 = 5,862 lb. CG from the datum = 885,957 / 5,862 ≈ 151.14 in, which rounds to about 151.1 inches. So the empty CG is approximately 151.1 inches aft of the datum.

Finding the empty center of gravity uses moments about a reference datum. Multiply each weight by its distance from the datum (its arm), sum those moments, then divide by the total weight to get the CG position relative to the datum.

Compute the moments: 3540 lb at 195.5 in gives 692,070 lb·in. The nose gear is 2322 lb at 83.5 in gives 193,887 lb·in. Total moment = 885,957 lb·in. Total empty weight = 3540 + 2322 = 5,862 lb.

CG from the datum = 885,957 / 5,862 ≈ 151.14 in, which rounds to about 151.1 inches.

So the empty CG is approximately 151.1 inches aft of the datum.