What is necessary for accurate weight data to determine the center of gravity (CG)?

To accurately determine the center of gravity (CG) of an aircraft, it is essential that the aircraft is weighed in a level flight attitude. This is crucial because the CG is dependent on the distribution of weight along the aircraft's length and width. When an aircraft is in a level attitude, it allows for the proper identification of the correct weight distributions and the corresponding moments that affect CG calculation.

Weighing the aircraft in any other attitude could distort the data, leading to incorrect calculations of the CG. For instance, if the aircraft is pitched up or down, the weight distribution will not accurately reflect how it would behave in level flight, which can severely impact performance and safety.

While empty weighing and weighing at maximum capacity can provide useful data, they do not directly address the requirement for level flight during measurement. Additionally, weight measured during takeoff does not allow for the determination of CG since the aircraft is not in a stable attitude for measurement. Thus, level flight attitude during weighing is fundamental to ensuring an accurate and reliable calculation of the CG.