FAA Private Pilot Airplane (PAR)Performance, Weight and BalanceMedium
A pilot determines the aircraft's current center of gravity (CG) is at 82.0 inches aft of the datum. The forward CG limit is 79.0 inches and the aft CG limit is 83.0 inches. If the pilot adds 50 lbs of cargo to a baggage compartment located at an arm of 100.0 inches, how will this affect the aircraft's CG?
- AThe CG will move aft, exceeding the aft limit.
- BThe CG will move forward, exceeding the forward limit.
- CThe CG will move forward, remaining within limits.
- DThe CG will move aft, remaining within limits.
Show answer & explanationAnswer & explanation
Correct answer: A. The CG will move aft, exceeding the aft limit.
Adding weight aft of the current CG will move the CG further aft. The current CG is 82.0 inches, and the aft limit is 83.0 inches. Adding 50 lbs at 100.0 inches (which is aft of both the current CG and the aft limit) will move the CG further aft, likely exceeding the 83.0-inch aft limit. To confirm, a moment calculation would be needed, but the directional shift is clear.
Why the other options are wrong
- B. Incorrect. Adding weight aft of the current CG will move the CG aft, not forward.
- C. Incorrect. Adding weight aft of the current CG will move the CG aft, not forward.
- D. Incorrect. The calculation shows it will exceed the aft limit.
CG Shift with Added Weight
Adding weight to an aircraft will shift the Center of Gravity (CG) in the direction of the added weight. The magnitude of the shift depends on the weight added and its arm relative to the current CG.
- Weight added forward of CG shifts CG forward.
- Weight added aft of CG shifts CG aft.
- Always verify new CG remains within approved limits.
Memory trick: Add Weight, CG Follows