User Guide

What does the Calculator do?

The Calculator is a program that allows you to calculate the weight-and-balance in order to load your airplane correctly for the flight. The Calculator checks both the takeoff CG location and the takeoff weight, as well as projects the CG location with the tanks empty. At the end, you can get a little printed report with the numbers and the analysis.

Using the Calculator

The Calculator allows you to choose an airplane from a list, and it then displays to you a little form in which you can enter the weights of passengers and baggage, and the amount of fuel in gallons. The form looks like this, at least for a six-place airplane with a forward baggage compartment:
The six boxes in the middle are the seats, the boxes in the wings are fuel tanks, and the two lonely boxes in front and back are the baggage compartments. The form will appear differently, depending on the actual number of seats and baggage compartments in the airplane of your choice. Please note that the weight must be specified in pounds, while the fuel is in gallons.

If you change the choice of airplane, the Calculator will try to preserve the entered weights of your passengers and baggage, unless the other airplane has fewer seats.

After loading the airplane, you should click the "Update Graph" button. This will update the loading graph with the numbers you have entered. For example, loading a Seneca II as shown above will cause the following display in the loading graph:

Although the maximum gross weight has not been exceeded, the CG is outside of the allowed envelope. You have to make some changes in the loading, for example, add more baggage to the aft compartment, or ask your companion to fly in the back, or fly with less than full fuel.

You can make changes in the form and click the "Update Graph" button again, until you are satisfied with the loading. At this point, if this is of interest, you can create a W&B report and print it out by clicking the "Generate Report" button.

What exactly does the Calculator check?

The Calculator will perform the following checks. First, it will make some checks to see if your data makes sense. It will make sure that you:
  1. Put a pilot in one of the front seats, weighing more than 50 pounds.
  2. Specify at least the minimum amount of fuel for this airplane.
  3. Specify at most the maximum amount of fuel this airplane can carry.
Next, the Calculator will calculate the CG location and takeoff weight. It will make sure that:
  1. The takeoff weight and CG location is within the envelope.
  2. The zero fuel weight does not exceed the additional limit, should that be specified for this airplane.
  3. It will warn you if the zero fuel CG location is outside of the envelope (a very rare occurrence unless the takeoff CG is outside as well).