FAA Aviation Mechanic General (AMG)Aircraft Drawings, Weight and BalanceHard
An aircraft weighing 4,600 lb has a CG located 92.0 in aft of the datum. A 100 lb baggage item is moved from fuselage station 150 to station 50. What is the new CG location?
- A92.00 in
- B94.17 in
- C97.83 in
- D89.83 in
Show answer & explanationAnswer & explanation
Correct answer: D. 89.83 in
Using the weight-shift formula, CG change = (weight moved × distance moved) ÷ total weight = (100 × 100) ÷ 4,600 = 2.17 in. Since the weight moved forward (from station 150 to 50), the CG shifts forward: new CG = 92.0 − 2.17 = 89.83 in.
Why the other options are wrong
- A. This ignores the weight shift entirely.
- B. This incorrectly adds the shift as if the weight moved aft.
- C. This uses an incorrect distance moved calculation.
Weight Shift Formula
When a known weight is moved a known distance within an aircraft, the resulting CG shift equals (weight moved × distance moved) ÷ total aircraft weight.
- CG shift direction matches the direction the weight was moved
- Formula: ΔCG = (weight moved × distance moved) ÷ total weight
- Used for balancing aircraft after cargo relocation
Memory trick: Shift weight, shift CG — same direction, proportionally smaller