weight balanceFAA-published sample question (FIA, Aug 2021)
Determine the condition of the aircraft: Pilot: 160 lb; 26 inch arm Passenger: 120 lb; 26 inch arm Baggage: 80 lb; 62 inch arm Fuel: 24 gal; 7 inch arm Airplane empty weight: 730.5 lbs Empty CG: 17 inches MAC: 59 inches MGTOW: 1,320 lbs
A
The aircraft is slightly over MGTOW with the CG aft of the aft limit of 37% MAC.
B
The aircraft is under MGTOW with the CG at 35.2% MAC.✓ Correct Answer
C
The CG is forward of the aft limit of 37% and the aircraft is 100 pounds under MGTOW.
Explanation
Total weight is 160 + 120 + 80 + 144 (24 gallons x 6) + 730.5 = 1,234.5 pounds, 85.5 pounds under the 1,320-pound maximum. Moments are 4,160 + 3,120 + 4,960 + 1,008 + 12,418.5 = 25,666.5, so the CG is at 25,666.5 / 1,234.5 = 20.8 inches, which is 20.8 / 59 = 35.2 percent MAC. The airplane is under maximum weight and not 100 pounds under.
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