When performing a hot refueling, which of the following is critical to check?

When performing a hot refueling, checking fuel quality is critical due to safety and operational reliability. During hot refueling, the aircraft’s engines are still running, which presents a unique set of hazards associated with potential fuel contamination or the introduction of air into the fuel system. Ensuring that the fuel meets specified quality standards minimizes the risk of engine performance issues or failures caused by contaminants.

In addition to the risk factors tied directly to hot refueling, maintaining fuel quality safeguards against future operational issues that could arise from using poor quality fuel. Because the engines are running during this procedure, any debris or water present in the fuel may directly affect engine operation, which can lead to catastrophic failures in flight.

While the other options mentioned are important for overall aircraft operation, they do not pertain as specifically to the immediate and urgent concerns presented during a hot refueling scenario. This makes fuel quality checks paramount in that specific context.