Weight and Balance Calculator

To work it out:

1. Press Tools in the bar at the top of any page, then Weight and Balance, or Weight and balance calculator at the foot.
2. The aircraft: type the N-number and press Look it up. The FAA registry fills in the make and model and the serial; for a type-certificated aircraft it links the Type Certificate Data Sheet, which gives the datum, the CG range and the maximum weight. An experimental aircraft’s envelope comes from the kit manufacturer.
3. The weighing: level, tanks empty, a calibrated scale under each wheel (AC 90-89C 2.13). For each wheel, the scale reading, the tare (chocks or blocks on the scale) and its arm from the datum; and the unusable fuel, added back. Without a weighing, enter the empty weight and its CG instead.
4. The envelope: its corners from the kit manufacturer’s weight and balance data, in order around it, so a sloped limit is drawn as it is. Where the aircraft has them, the utility and aerobatic categories’ envelopes go beside it, each with its own corners; the answer says which categories a loading is inside. Without corners, the forward and aft limits and the gross weight make a rectangle.
5. The loading: each row has its own name, weight and arm. It starts with Pilot, Passenger and Baggage, which you can rename, and Add a row gives up to 12. Fuel is its own rows, each tank named, in gallons with its own arm (worked at 6 lb a gallon), up to 4 with Add a tank; the zero-fuel loading empties every tank.
6. The empty weight and CG, the answer and the chart are worked out as you type. Work it out puts it all in the page’s address, for a link.

For the POH:

1. Download the chart (SVG) for a document, or (PNG) for anything that takes a picture.
2. Download the calculations (Excel) gives one workbook with four tabs: the weighing, the loading, the totals and CG, and the envelope check; the envelope chart sits on the Loading tab, under the loading. The weighing and loading tabs keep their working as formulas, so changing a number in the sheet works it out again.
3. From an aircraft: Weight & balance in the aircraft’s menu in MRO (and its card on the aircraft’s page), or in a Builders Log project’s row, opens the calculator for that aircraft with its saved calculations first.
4. Signed in with a membership, Save keeps the calculation on your account under a name, tied to one of your aircraft if you choose. Your saved calculations are listed at the top of the calculator, one group per aircraft; open one to carry on, Save changes, Save as new, or Remove it. Without a membership, what you saved before can still be opened and downloaded.
5. The report for the POH lays out the weighing, the empty weight and CG, the useful load, the envelope chart and the sample loading on one page, with lines to sign. Print it, or save it as a PDF from the print window.