Updated October 2026
Weight and balance is the check that an airplane's total weight is under its maximum and its center of gravity (CG) sits inside the limits in the POH. Multiply each weight by its arm to get a moment, add the weights and the moments, then divide total moment by total weight to find the CG. Our Piper Warrior's maximum gross weight is 2,325 lb.
It is arithmetic, not judgment, and it is the one preflight calculation that can make an airworthy airplane illegal to fly. 14 CFR 91.9(a) forbids operating outside the limitations in the approved flight manual, and the weight and CG limits are among them. The Private Pilot ACS tests it in Area I, Task F: compute weight and balance, correct an out-of-CG load, and confirm the airplane stays within limits through every phase of flight.
We fly three trainers with three very different loading stories. The weights below come from our own fleet pages. Where the worked example needs station arms and CG limits, we invented them for teaching and labeled them as such. When you fly, use the POH and the weight and balance record for the actual tail number.
Book A Discovery Flight — $229 Book A Free Consultation Call (818) 330-1318
Why Weight And Balance Matters (Forward CG, Aft CG, Overweight)
Overweight first, because it is the easiest to picture. The Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C, chapter 10) lists what extra weight costs: a higher takeoff speed and a longer takeoff run, a weaker climb, a lower ceiling, shorter range, slower cruise, higher stall and landing speeds and a longer landing roll. None of those is dramatic on its own. Stacked together on a hot afternoon at Van Nuys, they are.
Balance is subtler. A forward CG makes the airplane nose-heavy, and the handbook warns that the nose becomes hard to raise on takeoff and landing, to the point where a proper flare can become difficult or impossible. An aft CG is the dangerous one. It reduces longitudinal stability and the ability to recover from stalls and spins, and it makes the control forces light enough that overstressing the airplane gets easy.
That is why instructors watch the back seats and the baggage area of the Warrior more closely than the front. Weight placed far aft sits on a long arm, and a long arm moves the CG a long way.
The Terms: Datum, Arm, Moment, Station, Useful Load, Empty Weight
| Term | Meaning |
|---|---|
| Datum | An imaginary reference line chosen by the manufacturer. Every arm is measured from it, and it is station zero. |
| Arm | Horizontal distance from the datum to an item's CG, positive aft of the datum and negative forward of it. |
| Station | A location in the airplane identified by its distance in inches from the datum. |
| Moment | Weight multiplied by arm, in inch-pounds. |
| Basic empty weight | Standard empty weight plus any optional or special equipment installed. |
| Useful load | Occupants, baggage, usable fuel and drainable oil. It equals maximum gross weight minus basic empty weight. |
| Payload | Occupants, cargo and baggage only. |
| Center of gravity | The balance point, given in inches from the datum or as a percentage of the mean aerodynamic chord. |
Two standard weights from the same chapter do most of the work: avgas at 6 lb per US gallon and oil at 7.5 lb per gallon. Jet A is 6.8 lb per gallon, a number you will need only if you go on to fly turbines.
Moments get large quickly, so many handbooks divide them by 100 or 1,000 to keep the figures manageable. Check which convention your loading graph uses before you add anything up. Mixing the two up is the quickest way to a nonsense CG.
Reading The POH Loading Graph And CG Envelope
Section 6 of a standard POH is the weight and balance section, and it belongs to one tail number. It holds the airplane's as-weighed empty weight and empty CG, its equipment list, the arms for the seats, fuel and baggage, and the CG envelope. Our Piper Warrior page explains why two Warriors parked side by side can differ by more than a hundred pounds in empty weight.
Most light-airplane handbooks give two methods. The arithmetic method is a table with weight, arm and moment on each line. The graphical method uses a loading graph: find each item's weight on one axis, read its moment off the line for that station, then plot total weight against total moment on the envelope chart. Both give the same answer. The table is easier to check.
The envelope is a shape with weight up the side and CG or moment along the bottom, and your loaded point has to sit inside it. Many envelopes have a sloped forward edge, so the forward CG limit moves aft as the airplane gets heavier. Some airplanes also have a smaller utility-category envelope with tighter limits. The DA20-C1 we use for spin training has to be inside its utility envelope for that work.
Examiners like the follow-up question: the airplane is out of limits, so what do you move, and how far? The handbook's weight-shift formula answers it. Weight moved divided by total weight equals CG change divided by the distance the weight moved. In its own example, 100 lb moved 120 inches in an 8,000 lb aircraft shifts the CG 1.5 inches. Expect a version of the same question on the private pilot written exam.
A Worked Example: Two People And Full Fuel In The Piper Warrior
Three numbers here come from our Warrior fleet page: the 2,325 lb maximum gross weight, the 48 US gallons of usable fuel and a typical empty weight of about 1,350 lb. The arms and the CG limits are invented for teaching. These are example numbers, not for flight.
| Item | Weight (lb) | Arm (in), Invented | Moment (in-lb) |
|---|---|---|---|
| Basic empty weight | 1,350 | 86.0 | 116,100 |
| Student and instructor, front seats | 340 | 80.0 | 27,200 |
| Rear seats | 0 | 118.0 | 0 |
| Fuel, 48 gallons at 6 lb | 288 | 95.0 | 27,360 |
| Baggage, headsets and flight bags | 20 | 142.0 | 2,840 |
| Total | 1,998 | CG 86.8 | 173,500 |
Total weight is 1,998 lb, 327 lb under gross. The CG is 173,500 divided by 1,998, or 86.8 inches aft of the datum. In our invented envelope the limits at this weight run from 84.0 to 93.0 inches, so the airplane is inside on both counts.
Now add two friends in the back at 170 lb each. That is 340 lb on the 118-inch arm, another 40,120 inch-pounds. Total weight becomes 2,338 lb, 13 lb over gross, and the CG moves aft to 91.4 inches. Thirteen pounds over is still over.
The fix is fuel. Leave with 30 gallons instead of 48 and you remove 108 lb and 10,260 inch-pounds. The airplane now weighs 2,230 lb with the CG at 91.2 inches, inside the example envelope, with less range than before. Our Warrior page says it plainly: in most Warriors you carry full seats or full tanks, not both.
Cessna 162 And DA20: The Two-Seat Trainers And Their Limits
In the two-seaters, weight and balance is a real decision on almost every flight. The figures below are the typical values on our fleet pages. The weight and balance record for each tail number is the one that counts.
| Aircraft | Tail Numbers | Maximum Gross | Typical Useful Load | Usable Fuel | Left For People And Bags With Full Fuel |
|---|---|---|---|---|---|
| Cessna 162 Skycatcher | N60225, N7030B, N6039M, N179LC, N5208V, N52049 | 1,320 lb | About 450 to 490 lb | 24 gal, about 144 lb | Roughly 310 to 345 lb |
| Diamond DA20-C1 | N306EF, N308EF | 1,764 lb | About 580 to 600 lb | About 24 gal, about 144 lb | Roughly 435 to 455 lb |
| Piper Warrior PA-28-161 | N3034Q, N6312C | 2,325 lb | About 950 to 980 lb | 48 gal, about 288 lb | Roughly 660 to 690 lb |
The Skycatcher is the tight one. Two people at 170 lb each make 340 lb, which with full fuel puts a typical 162 at or over its 1,320 lb limit before anyone loads a flight bag. Most of our 162 flying leaves with partial fuel, and when it helps we pair a heavier student with a lighter instructor. A pattern lesson does not need full tanks, as long as you keep the reserve in 14 CFR 91.151: enough fuel to reach the first point of intended landing plus 30 minutes by day, or 45 at night.
The DA20-C1 has more room. Two average adults and a small bag with full fuel is a realistic load; two large adults may not be. Spin training in the DA20 happens inside its utility-category limits, which the spin course briefing covers.
If you are not sure where you fall, our page on whether there is a weight limit for flight training explains how we plan lessons around it. Training flights are planned individually. The fixed limits apply only to pre-sold discovery flights, 180 lb per person in the Warrior.
Fuel Burn And How CG Moves In Flight
Fuel is normally the only weight that changes in flight, and the airplane performs a little better as it burns off. Where the CG goes depends on where the tanks are. The PHAK points out that most small airplanes carry their fuel in the wings, close to the CG, so burning it moves the loaded CG only slightly.
Run it anyway. Take the two-person Warrior above and fly a two-hour lesson at the 8 to 9 gallons an hour our Warrior page gives for cruise. Call it 16 gallons, or 96 lb at the example fuel arm of 95.0 inches. Landing weight is 1,902 lb, the moment falls by 9,120 to 164,380, and the CG moves forward from 86.8 to 86.4 inches.
Small, as the handbook says. But it moved toward the forward limit, and with a heavy front-seat pair and little baggage that can matter. The ACS wording is deliberate: weight and balance within limits during all phases of flight, not only at engine start.
Free Weight And Balance Calculator
The formula is the same for every airplane. For each line, moment = weight × arm. Total weight is the sum of the weights, total moment is the sum of the moments, and CG = total moment ÷ total weight. With the example rows above: 1,350 × 86.0 = 116,100; 340 × 80.0 = 27,200; 288 × 95.0 = 27,360; 20 × 142.0 = 2,840. The weights add to 1,998 lb and the moments to 173,500 in-lb, and 173,500 ÷ 1,998 = 86.8 inches. Enter your own rows below with the empty weight, empty CG and arms from the record for the airplane you are flying. The calculator has no aircraft data built in, on purpose.
It does the arithmetic and nothing more. Whether the answer is inside the envelope is a question for the chart in your POH. If you would rather keep a weight and balance spreadsheet, four columns are all it needs: item, weight, arm and moment, with a total row at the bottom.
Weight, Density Altitude And A Summer Afternoon At Van Nuys
Van Nuys sits at about 800 feet, and on a hot summer afternoon the density altitude can be several thousand feet higher. Weight and density altitude hit the same numbers: takeoff distance, climb rate and how high you are by the time you cross the Sepulveda Basin. A Warrior near gross on a hot August afternoon climbs far more slowly than the same airplane solo on a January morning. Our guide to pressure altitude and density altitude covers the other half of that problem.
The Cessna 162 shows the combination most clearly. Its climb figure of about 890 feet per minute is a light-weight, cool-air number, and our 162 page notes that at gross on a hot Valley afternoon the real figure is a fraction of it.
Weight also moves maneuvering speed. Our page on maneuvering speed works out the Warrior's VA at lighter weights, and a student who has just done the weight and balance already has the number it needs. We put both on the kneeboard sheet before every cross-country.
Related Reading
- Piper Warrior PA-28-161 — weights, fuel, useful load and what is in each POH section.
- Is there a weight limit for flight training — how we plan lessons for larger students.
- Private pilot written exam — where the loading graph questions come from.
- Cessna 162 Skycatcher — the light sport trainer where fuel is the variable.
- Diamond DA20-C1 — the two-seat composite trainer and spin-training airplane.
- Maneuvering speed explained — the speed that falls as the airplane gets lighter.
Weight And Balance FAQ
How Do You Calculate Center Of Gravity?
Multiply each weight by its arm to get a moment, add up the weights and the moments, then divide the total moment by the total weight. The result is the CG in inches from the datum, which you check against the envelope in the POH.
What Is The Difference Between Useful Load And Payload?
Useful load is everything added to the empty airplane: occupants, baggage, usable fuel and drainable oil. Payload is only the occupants, cargo and baggage. Useful load equals maximum gross weight minus basic empty weight.
How Much Does Avgas Weigh?
6 lb per US gallon for weight and balance, according to the Pilot's Handbook of Aeronautical Knowledge. The Warrior's 48 usable gallons weigh about 288 lb, and the Cessna 162's 24 gallons about 144 lb.
Is An Aft CG Or A Forward CG More Dangerous?
Aft. The FAA says an aft CG reduces longitudinal stability and the ability to recover from stalls and spins, and makes control forces light enough to overstress the airplane. A forward CG makes the nose hard to raise, which is unpleasant but usually easier to manage.
Can I Use A Cessna 172 Weight And Balance Sheet For Another Airplane?
No. The arms, limits and empty weight belong to one type and one tail number. Even two Cessna 172s differ, because each airplane's empty weight and empty CG come from its own weight and balance record.
Is Weight And Balance On The Private Pilot Checkride?
Yes. Area I, Task F of the Private Pilot ACS asks you to compute weight and balance, correct out-of-CG loading errors and confirm the airplane stays within limits during all phases of flight. It appears on the written test as well.
Do The Numbers With An Instructor
Weight and balance becomes routine inside our private pilot course, and by the checkride it takes a couple of minutes. A 60-minute discovery flight from Van Nuys is $229 in the Warrior, with a 180 lb per person limit, and it is credited in full toward training if you enroll within 24 hours. For what the whole course costs, see flight school cost in Los Angeles, or book a free consultation and bring your questions about weight. Call (818) 330-1318, 9 AM to 9 PM, seven days.
Book A Discovery Flight — $229 Book A Free Consultation Call (818) 330-1318
