What does proper engine check during a run-up ensure?

The correct answer highlights the importance of ensuring that all engine instruments and systems are operational during a run-up. A proper engine check is a critical safety procedure performed before flight, typically while the aircraft is stationary and engines are running at a designated power setting. This check allows the pilot to verify that the engine is functioning correctly and all associated systems, such as fuel flow, oil pressure, and electrical systems, are operational.

This process not only aids in identifying potential mechanical issues before departure but also helps ensure that the aircraft is ready for the demands of flight. By confirming that engine performance metrics are within normal parameters, the pilot can proceed with greater confidence, knowing that the engine will perform as expected during the flight.

Other options focus on different aspects of flight preparation that, while important, are not directly related to engine performance verification during the run-up. Passengers' comfort, updated charts, and fuel levels are indeed essential for a safe flight; however, they are separate from the critical engine check process which is primarily concerned with the operational readiness of the aircraft's engine systems.