What should never be done when loading pallets onboard an aircraft?

When loading pallets onto an aircraft, gravity-loading should be avoided because it can lead to inadequate control and potential harm to both the personnel and the cargo. Gravity-loading can compromise the stability of the pallets and increase the risk of them shifting during transport, which may affect the balance of the aircraft. It also makes it difficult to ensure that the cargo is properly secured and loaded in compliance with safety regulations.

On the other hand, manually pushing pallets is a practice that may be used as long as it is done within safety protocols, while securing pallets tightly is essential for preventing movement during flight. Checking for proper fitting is also a necessary step to ensure that the pallets fit securely within the designated areas of the aircraft. Therefore, avoiding gravity-loading is crucial for maintaining safety and operational integrity when loading pallets.