Calculator
Example Data Table
| Item | Weight | Arm | Moment/1000 |
|---|---|---|---|
| Basic empty aircraft | 1639 lb | 39.29 in | 64.40 |
| Fuel, 35 gal | 210 lb | 48 in | 10.08 |
| Pilot and front passenger | 330 lb | 37 in | 12.21 |
| Rear passenger | 120 lb | 73 in | 8.76 |
| Baggage area 1 | 35 lb | 95 in | 3.33 |
Formula Used
Moment: Moment = Weight × Arm.
Moment/1000: Moment/1000 = Weight × Arm ÷ 1000.
Center of gravity: CG = Total moment ÷ Total weight.
Fuel weight: Fuel weight = Gallons × 6.
Normal forward limit: 35 inches at 1950 lb or less. It varies to 40 inches at 2450 lb.
Utility forward limit: 35 inches at 1950 lb or less. It varies to 36.5 inches at 2100 lb.
How to Use This Calculator
- Enter the current basic empty weight and arm.
- Add ramp fuel, taxi fuel, and expected trip fuel.
- Enter each occupant weight and station arm.
- Add baggage and custom equipment if needed.
- Select normal or utility category.
- Press calculate and review every phase result.
- Download CSV or PDF for records.
- Confirm all results with approved aircraft documents.
About this Cessna 172R Weight and Balance Calculator
This calculator helps a pilot organize loading data for a Cessna 172R. It follows the common weight, arm, and moment method used in aircraft balance work. Each station has a weight and an arm. The tool multiplies both values to find a moment. It then totals the moments and divides by total weight to estimate the center of gravity.
Why Weight and Balance Matters
An aircraft can be under maximum weight and still be out of balance. A forward center of gravity may require more elevator force. An aft center of gravity may reduce stability. Both conditions can affect takeoff, climb, landing flare, and stall behavior. That is why every loading case should be checked before flight.
Advanced Loading Checks
The form includes empty aircraft data, fuel, taxi fuel, trip fuel, seats, baggage areas, and custom equipment. It compares ramp, takeoff, and landing phases. It also checks baggage limits and category rules. You can edit arms when your aircraft records or seat positions require different stations.
Fuel and Phase Planning
Ramp weight uses fuel before taxi. Takeoff weight subtracts taxi and runup fuel. Landing weight subtracts planned trip fuel. These phase checks help show how balance moves as fuel burns. Fuel is normally forward of many cabin loads, so the center of gravity can move aft during flight.
Custom Aircraft Data
The empty weight and empty arm should come from current aircraft records. Do not rely on factory sample data when the airplane has avionics, paint, repairs, or equipment changes. Small changes can affect useful load. They can also change the calculated center of gravity.
Interpreting the Result
The result table shows weight, moment, center of gravity, forward limit, aft limit, and status. A pass means the calculated point is inside the selected envelope. A warning means one or more limits need review. The calculator also shows zero fuel weight, payload, fuel remaining, and useful load used.
Important Safety Note
This page is an estimate. Use the actual equipment list and current weight record for the specific aircraft. Always compare the result with the approved handbook, placards, supplements, and operating rules. Do not use sample numbers as official flight data each time.
FAQs
1. Is this calculator official flight data?
No. It is only a planning aid. Always use the approved handbook, current aircraft weight records, placards, and supplements for flight decisions.
2. What is arm in weight and balance?
Arm is the distance from the reference datum to the item center of gravity. It is measured in inches for this calculator.
3. What is moment?
Moment is weight multiplied by arm. This calculator also shows moment divided by 1000 to keep numbers shorter.
4. Why check ramp, takeoff, and landing?
Fuel burn changes aircraft weight and balance. Ramp, takeoff, and landing checks show how the loading changes during the planned flight.
5. What fuel weight does the calculator use?
It uses 6 pounds per gallon for aviation gasoline. Confirm the correct planning value for your aircraft and fuel documents.
6. Can I edit station arms?
Yes. Arms are editable because seat positions, equipment, and aircraft records may differ. Use the values approved for the specific aircraft.
7. What happens in utility category?
The calculator applies lower weight and CG limits. It also warns if rear seats or baggage areas are loaded.
8. Why did I get a review warning?
A warning appears when weight, CG, fuel, baggage, or category rules may be outside the calculator limits. Recheck all entries carefully.