If the reference datum line is placed at the nose of an airplane, how will all measurement arms be affected?

When the reference datum line is established at the nose of an airplane, all measurement arms will be represented as positive numbers. This is because the measurement arm is calculated as the distance from the reference datum to the center of gravity (CG) of the aircraft. Since the CG will be located aft of the nose, all distances measured in the direction toward the tail will yield positive values.

This method of measurement is a standard practice in weight and balance calculations, as it simplifies the determination of moments and the overall weight and balance analysis of the aircraft. Employing positive values for the arms helps ensure clarity in calculations, particularly when verifying weight distribution and ensuring the aircraft remains within its operational limits.

The fact that the measurement arms are associated with positive numbers reinforces the systematic approach to weighing and balancing aircraft, aiding in maintaining a clear and effective evaluation of aircraft configurations.