Which statement best describes what the pitot-static system measures?

The pitot-static system is a crucial component in aircraft that primarily measures airspeed, altitude, and vertical speed. This system combines inputs from the pitot tube, which captures dynamic air pressure (related to the aircraft's forward speed), and the static ports, which measure the ambient air pressure surrounding the aircraft.

The airspeed indicator derives its readings from the difference between dynamic and static air pressures, allowing the pilot to monitor how fast the aircraft is traveling through the air. The altimeter, which also relies on static pressure, provides the aircraft's altitude above sea level, and the vertical speed indicator, using changes in static pressure over time, indicates whether the aircraft is climbing or descending.

Other options do not accurately describe the function of the pitot-static system. Control surface positions pertain to the aircraft's flight control system, while engine performance metrics relate to the engine and its operation. Aircraft structural integrity is assessed through different systems and not through the pitot-static measurements. Thus, the best description of the pitot-static system's function is its ability to measure airspeed, altitude, and vertical speed.