A good weight and balance calculation is the keystone of flight testing an amateur-built aircraft. Accurately determining the aircraft’s takeoff weight and ensuring that the CG is within the aircraft’s design for each flight is critical to conducting a safe flight test.

The aircraft should be level when weighed, spanwise and fore and aft in accordance with the kit manufacturer’s instructions, and should be in the level flight position. It is highly recommended that the aircraft be weighed in an enclosed area using three calibrated scales. Bathroom scales are not recommended because they are not always accurate.