Weight and Balance

Weight and Balance

With a car, you have to put massive rocks in the trunk before added weight appreciably affects how the car drives. With an airplane, you must follow weight and balance limitations when loading an aircraft for safe flight. Extra weight — especially weight in the wrong location — can make flight unsafe or even impossible. That's why your cross-country trips as well as your FAA knowledge and practical tests will require you to understand your craft's weight and balance requirements.

It's a good thing that the plane's operating handbook includes weight and balance information as well as tips on how to calculate it. The aircraft's gross weight is the manufacturer's (and FAA's) documented weight limit including the pilot, passenger, instruments, luggage, fuel, and oil. So use your craft's weight and balance tables along with your E6B computer to make sure your craft is not overweight and the weight is properly distributed around the center of gravity before you go flying.

The operating handbook tells you the balance limits and how to load weight including passengers and luggage to stay within those limits. Here are some guidelines for calculating weight and balance in most small aircraft:

  • The center of gravity or balance point is calculated based on the weight of the load and its distance from a specific point on the craft, called the datum line.
  • The datum line for some aircraft is at the firewall behind the engine, while on other aircraft it's at the propeller; use whichever is suggested by the manufacturer.
  • The arm is the distance from a specific point, called the datum line, to the weight.
  • The moment is the arm multiplied by the weight.
  • The location of the center of gravity is the total moments divided by the total weight.

Your E6B computer or calculator, along with the operating handbook, will guide you in establishing the craft's balance around its center of gravity. The handbook will show you if the balance, as loaded, is within the required limits.