Plan a flight · weight and balance

Weight and balance

Pick the type, enter the aircraft's own empty weight and arm from its weight-and-balance record, then the people, bags and fuel. The calculator draws the type's centre-of-gravity envelope and shows where the loaded aircraft sits at takeoff, at landing and with no fuel. The aircraft's record and its manual govern; this is for planning.

The aircraft

Type

Tail number optional; the empty weight below is remembered on this device for it

Empty weight, lb from the aircraft's record Empty arm, inches or enter the moment instead Empty moment, lb-in as the record gives it (not divided by 1,000)

The load

Fuel at takeoff, gallons Fuel burned en route, gallons Weight per gallon, lb

Where it sits

Enter the aircraft and its load, then press "Work it out".

How to read it, and where the numbers come from

Everything in the aircraft has a weight and sits at an arm, a distance behind the type's datum. Weight times arm is the moment; the loaded centre of gravity is the total moment divided by the total weight. The type's manual allows a range of centre of gravity that narrows as the weight rises, drawn here as the envelope; a point outside it means the aircraft would be unsafe to fly as loaded: nose-heavy or tail-heavy, or simply too heavy.

The limits and stations for the listed types are taken from the FAA's type certificate data sheets and the manuals, and each type names its sheet. They are to be checked against your own manual before you rely on them, and they never replace it: equipment, modifications and the category of operation can change the limits for one aircraft. The empty weight and arm are different for every aircraft and come from its own weight-and-balance record, which changes with every modification; that is why you enter them, and why they are kept only on your device, never sent to this site.

Fuel is counted at 6 lb a gallon for aviation gasoline (about 6.7 for jet fuel); change it for your fuel. Oil is included in the empty weight for most types. Density altitude for the departure field is on each airport's page.