Typical value for PA-28-180. Refer to your aircraft's POH.
Calculated as (Empty Weight * Arm). From your POH's Weight & Balance section.
Weight of the pilot in pounds (lbs).
Distance from datum in inches (in). Typically 37.5 for front seats.
Weight of the front passenger in pounds (lbs).
Distance from datum in inches (in). Typically 37.5 for front seats.
Weight of the first rear passenger in pounds (lbs).
Distance from datum in inches (in). Typically 49.5 for rear seats.
Weight of the second rear passenger in pounds (lbs).
Distance from datum in inches (in). Typically 59.5 for rear seats.
Total weight of fuel in pounds (lbs). (Gallons * 6 lbs/gal).
Distance from datum in inches (in). Typically 42.0 for PA-28 wing tanks.
Weight of baggage in pounds (lbs). Check placard for limits.
Distance from datum in inches (in). Typically 71.0 for baggage area.
Flight Conditions
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Center of Gravity (CG)
— lbs
Total Weight
— lb-in
Total Moment
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CG Range
Moment = Weight × Arm (distance from datum). Total Moment = Sum of all individual moments. Total Weight = Sum of all weights. CG = Total Moment / Total Weight.
Center of Gravity (CG) Envelope for PA-28-180 (Typical Values)
Flight Load Summary
Item
Weight (lbs)
Arm (in)
Moment (lb-in)
Empty Aircraft
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—
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Pilot
—
—
—
Front Passenger 1
—
—
—
Rear Passenger 1
—
—
—
Rear Passenger 2
—
—
—
Fuel
—
—
—
Baggage
—
—
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TOTALS
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What is PA-28-180 Weight and Balance?
The PA-28-180 weight and balance calculation is a critical pre-flight procedure for pilots operating the popular Piper Cherokee 180. It ensures that the aircraft's total weight and its center of gravity (CG) remain within the certified limits defined in the aircraft's Pilot's Operating Handbook (POH). Operating an aircraft outside these limits can lead to a loss of control, reduced performance, and potentially a catastrophic accident. Understanding your PA-28-180 weight and balance is not just a regulatory requirement; it's a fundamental aspect of safe aviation.
Who should use it? Any pilot flying a Piper PA-28-180 (or similar PA-28 variants with comparable weight and balance characteristics) must perform this calculation before each flight. This includes private pilots, commercial pilots, flight instructors, and anyone else at the controls. It's essential for determining how much payload (passengers, baggage, fuel) can be safely carried.
Common misconceptions about weight and balance often revolve around its complexity. Some pilots may believe it's only for complex aircraft or that standard loading scenarios are always safe. However, even seemingly minor changes in passenger weight, fuel load, or baggage can shift the CG. Another misconception is that if the total weight is below the maximum, the aircraft is automatically safe; this ignores the crucial CG location. Proper PA-28-180 weight and balance is paramount.
PA-28-180 Weight and Balance Formula and Mathematical Explanation
The core of weight and balance calculation relies on the principle of moments. A moment is created when a weight is placed at a distance from a reference point, known as the datum.
The fundamental formula is:
Moment = Weight × Arm
Where:
Weight: The mass of an object (e.g., pilot, fuel, aircraft empty weight) in pounds (lbs).
Arm: The horizontal distance from the aircraft's datum (a reference point, often the firewall or wing leading edge) to the center of gravity of the weight, measured in inches (in).
Moment: The product of weight and arm, measured in pound-inches (lb-in).
To calculate the aircraft's overall weight and balance:
Calculate Individual Moments: For each item (empty aircraft, pilot, passengers, fuel, baggage), multiply its weight by its respective arm.
Sum All Weights: Add up the weights of the empty aircraft, all occupants, fuel, and baggage. This gives the Current Total Weight.
Sum All Moments: Add up all the individual moments calculated in step 1. This gives the Current Total Moment.
Calculate Center of Gravity (CG): Divide the Current Total Moment by the Current Total Weight.
CG = Current Total Moment / Current Total Weight
The calculated CG (in inches from the datum) must then be compared against the allowable CG range specified in the PA-28-180 POH. This range typically varies with the aircraft's weight.
Variables Table
PA-28-180 Weight & Balance Variables
Variable
Meaning
Unit
Typical Range / Notes
Empty Weight
Weight of the aircraft including unusable fuel, fixed equipment, and full oil.
lbs
~1300 – 1450 lbs (Check POH)
Empty Weight Moment
Moment of the empty aircraft about the datum.
lb-in
Calculated from POH. ~50,000 – 60,000 lb-in is common.
Occupant/Baggage Weight
Weight of pilot, passengers, and baggage.
lbs
Individual: ~100-250 lbs. Max Baggage: ~100-150 lbs.
Occupant/Baggage Arm
Distance from datum to the CG of the item.
in
Pilot/Front Pass: ~37.5 in. Rear Pass: ~49.5 – 59.5 in. Baggage: ~71.0 in.
Fuel Weight
Weight of usable fuel on board.
lbs
(Gallons × 6 lbs/gal). PA-28-180 typically has 48 gal usable = ~288 lbs max.
Fuel Arm
Distance from datum to the CG of the fuel tanks.
in
Typically ~42.0 in for wing tanks.
Total Weight
Sum of all weights on board.
lbs
Must be <= Max Takeoff Weight (e.g., 2325 lbs for PA-28-180).
Total Moment
Sum of all moments (Weight x Arm) for items on board.
lb-in
Varies significantly with loadout.
Center of Gravity (CG)
The calculated balance point of the aircraft.
in
Must fall within the allowable CG range for the current weight.
Allowable CG Range
The weight-dependent CG limits from the POH.
in
e.g., 30.0 in to 40.0 in at 2300 lbs. Always check POH.
Practical Examples (Real-World Use Cases)
Let's illustrate the PA-28-180 weight and balance calculation with two common scenarios. We'll assume the following aircraft specifics from the POH:
Empty Weight: 1350 lbs
Empty Weight Moment: 54000 lb-in
Max Takeoff Weight: 2325 lbs
Allowable CG Range: 30.0 in to 40.0 in (at 2300 lbs and below)
Datum: Firewall
Arms: Pilot/Front Pass: 37.5 in, Rear Pass 1: 49.5 in, Rear Pass 2: 59.5 in, Fuel: 42.0 in, Baggage: 71.0 in
Example 1: Local Flight with Two Adults
A pilot and one adult passenger plan a short local flight. They plan to carry half the usable fuel and some baggage.
Interpretation: The calculated CG of 40.56 inches is slightly outside the allowable range of 30.0 – 40.0 inches. This indicates the aircraft is too nose-heavy for this loading condition. The pilot should consider reducing weight from the front, reducing baggage, or carrying more fuel (if within weight limits) to bring the CG forward.
Example 2: Cross-Country Flight with Full Load
Two adults and two children plan a cross-country trip with full usable fuel.
Interpretation: The total weight of 2258 lbs is below the Max Takeoff Weight of 2325 lbs. However, the calculated CG of 42.75 inches is well beyond the allowable rearward limit of 40.0 inches. This loading is unsafe and must be rectified. The pilot could remove baggage, reduce passenger weight (if possible), or potentially shift weight forward if there were forward compartments, though this is uncommon in the PA-28. This scenario highlights the importance of checking both total weight and CG.
How to Use This PA-28-180 Weight and Balance Calculator
Using this calculator is straightforward and designed to provide quick, accurate results for your PA-28-180 flight planning.
Gather Aircraft Data: Locate your PA-28-180's specific POH. You'll need the Empty Weight, Empty Weight Moment, and the Allowable CG Range for various weights. Note the standard Arms for the pilot, passengers, fuel, and baggage stations.
Input Aircraft Empty Weight & Moment: Enter your aircraft's specific Empty Weight and Empty Weight Moment into the designated fields. These are foundational values.
Enter Occupant & Baggage Details: Input the weight of each pilot and passenger (in pounds) and the weight of any baggage (in pounds).
Enter Fuel Load: Input the total weight of usable fuel you intend to carry. Remember that 1 gallon of aviation fuel weighs approximately 6 lbs. Calculate `Gallons * 6 = Fuel Weight`.
Verify Station Arms: Ensure the correct Arm (distance from datum) is entered for each item. The calculator provides typical values, but your POH is the ultimate authority.
Click Calculate: Press the "Calculate" button. The calculator will instantly compute the Total Weight, Total Moment, and the resulting Center of Gravity (CG).
Interpret the Results:
Main Result (CG): The primary output shows your aircraft's calculated CG in inches from the datum.
CG Range: This displays the allowable CG range for your aircraft's current weight, as defined in the POH.
Comparison: Visually or mentally compare your calculated CG against the allowable range. If your CG falls within the range, your PA-28-180 is within weight and balance limits. If it's outside, you must adjust the load.
Total Weight: Check that the Total Weight is less than or equal to the Maximum Takeoff Weight specified in the POH.
Load Summary Table: Review the table for a breakdown of each component's contribution to the total weight and moment.
Chart: The dynamic chart provides a visual representation of your CG's position relative to the operational envelope.
Make Flight Decisions: Based on the results, decide if the current loading is safe. If not, adjust fuel, baggage, or passenger loads and recalculate. This PA-28-180 weight and balance tool is key to safe flight planning.
Reset or Copy: Use the "Reset" button to clear fields and start over with default sensible values. Use "Copy Results" to save the summary data for your flight log.
Key Factors That Affect PA-28-180 Results
Several factors significantly influence your PA-28-180's weight and balance calculations and should be carefully considered for every flight:
Occupant and Baggage Weights: This is often the most variable aspect. Actual weights can differ from estimates. Weighing passengers and baggage, especially on longer trips or with full loads, is highly recommended. Even a few pounds difference per person can affect the CG.
Fuel Load: The PA-28-180 typically has a significant fuel capacity. Carrying full tanks adds substantial weight and moment, usually well aft of the empty aircraft's CG, pushing it rearward. Conversely, carrying minimal fuel (e.g., for a short flight) will result in a forward CG shift. Accurately calculating fuel weight (gallons × 6 lbs/gal) is crucial.
Aircraft Empty Weight and CG: While fixed for a specific aircraft, the empty weight and its associated moment are the baseline. Any changes to the aircraft (e.g., installing new equipment) require updating these figures, which will impact all subsequent calculations. Maintaining an up-to-date Weight and Balance sheet is vital.
Station Arms: The defined arms for different seating positions and baggage compartments are critical. Ensuring occupants and baggage are positioned correctly within their designated areas (e.g., not overloading the forward seats with heavy baggage) is essential. Incorrect arm values lead to inaccurate moment calculations.
Baggage Compartment Limitations: The PA-28-180 has a specific weight limit for the baggage compartment (e.g., 100 or 150 lbs depending on model) and often a forward limit for placing heavy items. Exceeding this weight or placing it too far forward/aft can compromise the CG envelope.
In-flight Changes: As fuel is consumed during flight, the aircraft's total weight decreases, and the CG typically shifts forward (as fuel weight is often located near the CG or slightly aft). While this calculator focuses on the pre-flight condition, understanding this shift is important for longer flights. The CG will move towards the average CG of the remaining fuel.
Equipment Changes: Installing optional equipment (like avionics upgrades, long-range tanks, or STOL kits) will alter the empty weight and/or empty weight moment. These changes must be professionally documented and incorporated into the aircraft's official Weight and Balance records. Relying on outdated information can lead to dangerous miscalculations.
Frequently Asked Questions (FAQ)
What is the maximum takeoff weight for a PA-28-180?
The maximum takeoff weight for most PA-28-180 models is 2325 lbs. However, always verify this exact figure in your specific aircraft's POH, as variations exist between different serial numbers and modifications.
Where do I find my aircraft's Empty Weight and Moment?
This information is found in the aircraft's Weight and Balance Record or Equipment List, which is part of the aircraft's official records. It is derived from the POH data and adjusted for installed equipment.
What are the standard CG limits for the PA-28-180?
The allowable CG range is typically weight-dependent. A common range for the PA-28-180 at or below 2300 lbs is approximately 30.0 inches to 40.0 inches aft of the datum (often the firewall). You MUST consult your specific POH for the exact limits applicable to your aircraft's current weight.
Can I use this calculator if my aircraft is modified (e.g., STOL kit, larger tanks)?
This calculator uses typical arms and weights. If your PA-28-180 has modifications like long-range fuel tanks or different baggage area configurations, you must input the correct, updated arms and weights as specified by the modification's documentation or your aircraft's revised Weight and Balance records. Always use data from your official aircraft records.
What happens if my CG is outside the allowable range?
Operating an aircraft outside its CG limits is prohibited and extremely dangerous. If your calculation shows the CG is too far forward or aft, you must adjust the load. This might involve removing baggage, reducing fuel, or rearranging occupants if possible. You cannot legally take off until the CG is within limits.
How often should I check my PA-28-180 weight and balance?
You must check it before every flight, especially if the loading conditions change from the previous flight. Any change in fuel, passengers, or baggage requires a recalculation. If you install new equipment, the aircraft's empty weight and moment must be officially updated.
Does the calculator account for unusable fuel?
This calculator assumes you are inputting the weight of *usable* fuel. The aircraft's empty weight typically includes unusable fuel. When calculating fuel load, ensure you're only accounting for fuel you can actually use in flight.
What is the "moment" and why is it important?
Moment (Weight x Arm) is a measure of the tendency of a weight to rotate about the datum. It's used because it allows us to sum up the effects of different weights at different locations. Calculating the total moment and total weight allows us to find the single point (the CG) where the entire aircraft's weight could be concentrated and still balance. It's the key to understanding the aircraft's stability and control.