If a pilot and copilot together weigh 400 pounds in an aircraft with an empty weight of 1,271 pounds, what is necessary for the CG to remain within limits?

To ensure the center of gravity (CG) remains within limits, it is essential to maintain operations at or below the maximum weight capacity. This is because exceeding the maximum weight can shift the CG outside of specified limits, which can adversely affect the aircraft’s performance and handling characteristics. The CG is influenced not just by the total weight of the aircraft but also by the distribution of that weight.

When the aircraft's weight is kept at or below the maximum capacity, it increases the likelihood that the CG will stay within the allowable range, especially when considering the loading of passengers, cargo, and fuel. Operating above maximum weight jeopardizes the safety and performance of the aircraft, as it could lead to issues such as increased stall speed, reduced climb performance, and more difficulty in handling.

While monitoring loading configurations and making incremental weight adjustments can help manage the CG, these practices alone don’t ensure that the overall weight remains within safe limits, nor do they address the importance of not exceeding maximum weight capacity directly. In this context, option D is critical for maintaining safe flight operations.