Under what condition should the fueling unit not be left unattended?

• A. while it is connected to the aircraft
• B. while it is connected to the ground
• C. while fueling is paused
• D. when the operator is in the restroom

Answer: (A)

Fueling is at its most hazardous when fuel is actively being transferred to the aircraft. The unit should not be left unattended while it is connected to the aircraft because any leak, spill, or equipment fault can escalate quickly into a fire or dangerous situation near the aircraft, and a quick shutoff or corrective action is needed. Continuous supervision allows immediate response to problems such as a sudden fuel leak, pressure anomaly, or equipment malfunction, and ensures bonding/grounding remains effective. Being connected to the ground or fueling being paused reduces some risks, but the critical moment requiring supervision is the actual connection to the aircraft during fueling.