Weight and balance is really just a seesaw problem. Get comfortable with the seesaw and the FAA written questions become straightforward arithmetic.

Two things must be true

The aircraft is at or below its maximum gross weight.
The center of gravity (CG) falls within the manufacturer's forward and aft limits.

The only formula you need

Moment = weight × arm. Add up every moment (people, fuel, baggage, the empty airplane), add up every weight, then divide total moment by total weight to get the CG. Compare that CG to the limits in the POH.

Why CG matters

Too far forward and the airplane is nose-heavy and hard to flare; too far aft and it becomes dangerously unstable and hard to recover from a stall. The envelope keeps you in the controllable, stable zone.

A worked example

Say total moment is 204,400 lb-in and total weight is 2,205 lb. CG = 204,400 ÷ 2,205 ≈ 92.7 inches aft of datum. If the POH allows 89–96 inches, you're in limits — and under max gross. Good to go.

Test-day tip

Work neatly in a little table: item, weight, arm, moment. Sum the columns, divide, compare. The math is easy; sloppy bookkeeping is what trips people up.

Frequently asked questions

Can the airplane be in limits but still unsafe?

It can be legal yet poorly suited to conditions (e.g., heavy on a hot, high day). Weight and balance is necessary, not sufficient — always check performance too.

Our built-in E6B and worked explanations make these click: study free.