Which instruments are connected to an aircraft's static pressure system only?

Which instruments are connected to an aircraft's static pressure system only?

• A. Vertical speed indicator and cabin altimeter
• B. Airspeed indicator and variometer
• C. Heading indicator and attitude indicator
• D. Turn-and-slip indicator and altimeter

Answer: (A)

The vertical speed indicator and cabin altimeter are both instruments that rely solely on the static pressure system of the aircraft to function. The vertical speed indicator measures the rate of climb or descent by detecting changes in static pressure, which corresponds to altitude changes. It utilizes the static pressure input from the static line to report vertical movement. Similarly, the cabin altimeter provides altitude readings based on the static pressure level outside the aircraft. It senses the ambient air pressure and translates that into altitude readings, reflecting how high the aircraft is relative to sea level. In contrast, other instruments listed depend on different pressure sources or combinations of static and dynamic pressure systems. For instance, the airspeed indicator, while it does use static pressure, also relies on dynamic pressure from the pitot tube. The heading and attitude indicators typically utilize a gyroscopic system rather than static pressure. The turn-and-slip and altimeter instruments have different calibration methods alongside static pressure but also functionality that does not stem solely from the static system. Therefore, the only instruments clearly connected exclusively to the static pressure system are the vertical speed indicator and cabin altimeter.

The vertical speed indicator and cabin altimeter are both instruments that rely solely on the static pressure system of the aircraft to function. The vertical speed indicator measures the rate of climb or descent by detecting changes in static pressure, which corresponds to altitude changes. It utilizes the static pressure input from the static line to report vertical movement.

Similarly, the cabin altimeter provides altitude readings based on the static pressure level outside the aircraft. It senses the ambient air pressure and translates that into altitude readings, reflecting how high the aircraft is relative to sea level.

In contrast, other instruments listed depend on different pressure sources or combinations of static and dynamic pressure systems. For instance, the airspeed indicator, while it does use static pressure, also relies on dynamic pressure from the pitot tube. The heading and attitude indicators typically utilize a gyroscopic system rather than static pressure. The turn-and-slip and altimeter instruments have different calibration methods alongside static pressure but also functionality that does not stem solely from the static system. Therefore, the only instruments clearly connected exclusively to the static pressure system are the vertical speed indicator and cabin altimeter.