Professional Flight Planning Tool for Archer II/III Aircraft
Aircraft Loading Data
Enter the specific empty weight from your aircraft's POH.
The center of gravity location of the empty aircraft.
Arm: 80.5 inches
Arm: 118.1 inches
Arm: 142.8 inches (Max 200 lbs)
Baggage exceeds 200 lbs limit.
Arm: 95.0 inches (Max 48 gal / 288 lbs)
Fuel exceeds 48 gallons capacity.
Center of Gravity (CG)
—
WITHIN LIMITS
Total Weight
— lbs
Total Moment
—
Useful Load Remaining
— lbs
Loading Manifest
Item
Weight (lbs)
Arm (in)
Moment (in-lbs)
CG Envelope Plot
Chart shows Normal Category limits for PA-28-181.
What is a Piper PA-28-181 Weight and Balance Calculator?
A piper pa-28-181 weight and balance calculator is a critical flight planning tool designed specifically for the Piper Archer II and Archer III aircraft. It allows pilots to determine if their aircraft is loaded within the certified limits for safe operation. Before every flight, a pilot must ensure that the total weight of the aircraft does not exceed the maximum gross weight and that the Center of Gravity (CG) falls within the approved envelope.
This tool is essential for student pilots, private owners, and flight instructors operating the PA-28-181. Unlike generic calculators, this tool uses the specific "arms" (distances from the datum line) defined by the manufacturer for the Archer series, ensuring precision in flight safety calculations.
Common misconceptions include assuming that if the seats are full, the plane is still safe to fly. In reality, a fully loaded Archer with full fuel often exceeds the maximum gross weight, requiring a reduction in fuel or baggage to remain legal and safe.
Piper PA-28-181 Weight and Balance Formula
The calculation relies on the principle of moments. A "moment" is the rotational force created by a weight located at a specific distance from a reference point (the datum).
The Core Formulas:
Moment = Weight × Arm
Total Weight = Sum of all weights (Empty Aircraft + Pilot + Pax + Fuel + Baggage)
Total Moment = Sum of all moments
Center of Gravity (CG) = Total Moment / Total Weight
Variable Definitions
Variable
Meaning
Unit
Typical PA-28-181 Value
Weight
Mass of the item
lbs
Varies
Arm
Distance from Datum
inches
80.5 (Front), 118.1 (Rear)
Moment
Rotational force
in-lbs
Weight × Arm
Datum
Reference line
–
78.4″ ahead of wing leading edge
Practical Examples (Real-World Use Cases)
Example 1: The "Hundred Dollar Hamburger"
Two pilots fly to a nearby airport for lunch. The aircraft has full fuel.
Empty Weight: 1,590 lbs (Arm 87.5)
Front Seats: 380 lbs (Two 190lb adults)
Rear Seats: 0 lbs
Fuel: 48 gallons (288 lbs)
Baggage: 10 lbs
Result: Total Weight is 2,268 lbs. This is well below the 2,550 lbs max gross weight. The CG is calculated to be roughly 88.2 inches, which is comfortably within the envelope. This is a safe and legal loading configuration.
Example 2: Family Trip with Luggage
A pilot takes three passengers and heavy luggage.
Empty Weight: 1,590 lbs
Front Seats: 340 lbs
Rear Seats: 300 lbs
Baggage: 100 lbs
Fuel: 48 gallons (288 lbs)
Result: Total Weight is 2,618 lbs. This exceeds the Max Gross Weight of 2,550 lbs by 68 lbs. The pilot must either reduce fuel load or remove baggage to fly legally. Using the piper pa-28-181 weight and balance calculator helps identify this danger immediately.
How to Use This Piper PA-28-181 Weight and Balance Calculator
Enter Aircraft Data: Input the Basic Empty Weight and Arm found in your specific aircraft's Weight and Balance sheet (Section 6 of the POH).
Input Payload: Enter the weights for the pilot, front passenger, rear passengers, and baggage.
Add Fuel: Enter the fuel in gallons. The calculator automatically converts this to pounds (6 lbs/gal).
Review Results: Check the "Status" badge. Green means safe; Red means you are overweight or out of CG limits.
Check the Chart: Look at the visual graph to see where your CG falls relative to the forward and aft limits.
Key Factors That Affect Weight and Balance Results
Several factors influence the outcome of your piper pa-28-181 weight and balance calculator results:
Fuel Burn: As you fly, you burn fuel. Since the fuel tank arm (95.0″) is different from the empty CG, your CG will shift during flight. Always check landing weight and CG as well.
Baggage Placement: The baggage compartment has a long arm (142.8″). Heavy items here have a massive effect on moving the CG aft, potentially causing instability and poor stall recovery characteristics.
Density Altitude: While not part of the W&B formula directly, a heavy aircraft performs significantly worse in high density altitude. Being at max gross weight on a hot day may prevent a safe climb.
Equipment Changes: If new avionics are installed, the Basic Empty Weight and Arm change. Ensure you are using the most current data for your airframe.
Passenger Distribution: Moving a heavy passenger from the rear seat to the front seat moves the CG forward, increasing stability but slightly increasing stall speed.
Zero Fuel Weight: Ensure that the structural limitations of the wings are respected, though the Archer typically relies on Max Gross Weight as the primary limiter.
Frequently Asked Questions (FAQ)
What is the maximum gross weight for a Piper Archer II/III?
The standard maximum gross weight for the PA-28-181 Archer II and III is 2,550 lbs in the Normal Category.
What happens if the CG is too far aft?
An aft CG makes the aircraft less stable. It becomes difficult to recover from a stall or spin, and the elevator controls may become overly sensitive. It is extremely dangerous.
What is the standard fuel weight used in calculations?
Aviation gasoline (Avgas 100LL) is calculated at 6.0 pounds per gallon.
Can I use this calculator for a Piper Warrior (PA-28-161)?
No. The Warrior has different weight limits and moment arms. You must use a calculator specific to the PA-28-161.
Does the CG change as fuel is burned?
Yes. Since the fuel is located at station 95.0, burning fuel reduces weight at that station, shifting the CG. You should verify that your landing CG is also within limits.
What is the "Datum" line?
The datum is an imaginary vertical plane from which all horizontal distances (arms) are measured. In the PA-28-181, it is located 78.4 inches ahead of the wing leading edge.
Is the baggage limit strictly 200 lbs?
Yes, the baggage compartment is structurally limited to 200 lbs, regardless of whether you have remaining useful load.
How do I find my aircraft's Basic Empty Weight?
Look in Section 6 (Weight and Balance) of the Pilot's Operating Handbook (POH) specific to your tail number. It is updated whenever equipment is added or removed.