Free sim
Weight & Balance
Every airplane has a weight limit and a balance limit, and you have to be inside both — at takeoff and after the fuel burns off. Load a sample trainer below: each item adds weight at its arm (its distance from the datum), the moments sum, and the center of gravity is just total moment ÷ total weight. Watch the dot land inside the envelope — or not.
These are sample trainers with representative numbers — the picture, not your airplane. To run your own empty weight, arms, and envelope, use the Weight & Balance calculator.
● takeoff (current fuel) · ○ zero fuel — Sample data (C172S POH-class, datum = firewall). Verify against your POH.
Cessna 172S. Takeoff weight 2280 pounds, CG 40.5 inches — Within limits. With the tanks dry, CG 39.6 inches — Within limits.
Two failure modes, two different fixes. Too heavy is a weight problem — no amount of CG shuffling fixes it; you offload. Out of CGis a balance problem — you shift or remove load until the dot is back in the box. And because the fuel sits at its own arm, burning it moves the CG: the hollow dot is where you'll be with the tanks dry, so a load that's legal at takeoff can walk to the aft limit by the time you land — which is exactly why the examiner checks both ends of the burn. These are samplenumbers; your airplane's real empty weight and CG come off its own weighing record, and the POH always wins.
Drilling for the checkride?
Walking the examiner through a weight & balance — datum, arm, moment, and defending the result against the envelope — is chapter 4 territory in our ACS-organized Private Pilot Quick-Review Study Guide, right alongside takeoff and landing performance and the density-altitude math.