Cessna 172 Weight and Balance Calculator
Total Ramp Weight:
0 lbs
Total Moment:
0 lb-in
Center of Gravity (CG):
0 in
Understanding Cessna 172 Weight and Balance
The Cessna 172 is one of the most popular training aircraft in the world, but its safety depends heavily on staying within the "envelope" defined by the manufacturer. Operating outside of these limits can drastically change the aircraft's stall characteristics, stability, and ability to recover from spins.
Key Definitions
- Arm: The horizontal distance in inches from the reference datum line to the center of gravity of an item. For the C172, the datum is usually the front face of the firewall.
- Moment: The product of the weight of an item multiplied by its arm (Weight x Arm).
- Center of Gravity (CG): The point at which the aircraft would balance if suspended. Calculated by dividing Total Moment by Total Weight.
Standard Arms for Cessna 172
While you should always consult your specific Pilot's Operating Handbook (POH), standard values for a Cessna 172N/P model typically include:
- Front Seats: 37 inches
- Rear Seats: 73 inches
- Fuel (6 lbs/gal): 48 inches
- Baggage Area 1: 95 inches
- Baggage Area 2: 123 inches
Example Calculation
If your empty weight is 1,450 lbs with a moment of 56,500 lb-in, and you add a 170 lb pilot (37″ arm) and 40 gallons of fuel (240 lbs at 48″ arm):
- Pilot Moment: 170 * 37 = 6,290 lb-in
- Fuel Moment: 240 * 48 = 11,520 lb-in
- Total Weight: 1,860 lbs
- Total Moment: 74,310 lb-in
- Final CG: 74,310 / 1,860 = 39.95 inches
At 1,860 lbs, a CG of 39.95 inches is well within the typical allowable range of 35 to 47 inches.