Who determines the location of the datum on an aircraft?

The location of the datum on an aircraft is determined by the aircraft manufacturer. The datum is a reference point on the aircraft from which measurements, such as weight and balance, are taken. It is crucial for maintaining the aircraft's stability and performance characteristics.

The manufacturer specifies this location during the design and certification process, ensuring that it adheres to the aircraft's structural and functional design requirements. This standardization is important for consistency across the same aircraft model, as it provides a uniform reference that mechanics and operators can rely on when performing weight and balance calculations.

While the FAA sets regulations that encompass many aspects of aircraft operation and safety, including weight and balance practices, it is ultimately the manufacturer's responsibility to establish where the datum point is located based on the aircraft's design criteria. Other parties, such as the aircraft owner or flight crew, do not have authority in determining this reference point; they must follow the specifications set by the manufacturer.