Which of the following duties is considered safety-sensitive in a flight operation environment?

In a flight operation environment, performing pre-flight checks is deemed a safety-sensitive duty because it directly impacts the safety of the aircraft and its passengers. These checks include inspecting critical components of the aircraft, ensuring that all systems are functioning properly, and verifying that safety protocols are followed before takeoff. If these checks are not conducted thoroughly or accurately, it can lead to serious safety risks, including mechanical failures or accidents during the flight.

The other duties listed do not have the same critical impact on the safety of the flight. While providing customer service, managing office paperwork, and cleaning the aircraft cabin are important roles within the operation, they do not directly affect the aircraft's readiness for flight in terms of safety oversight. Hence, they are not categorized as safety-sensitive like performing pre-flight checks.