Which instruments are affected by static pressure?

The instruments that are affected by static pressure are the altimeter, vertical speed indicator, and airspeed indicator.

The altimeter measures the aircraft's altitude by comparing the atmospheric pressure outside the aircraft to a pre-measured standard atmospheric pressure set within the instrument. When the static pressure changes, the altimeter responds accordingly, indicating a change in altitude.

The vertical speed indicator utilizes static pressure as well. It measures the rate of climb or descent by detecting the rate of change of static pressure. When an aircraft climbs or descends, the static pressure alters, and the vertical speed indicator translates this change into a visual representation of the ascent or descent rate.

The airspeed indicator also relies on static pressure but in a different way. It compares the dynamic pressure from the air entering the pitot tube (which senses the aircraft's speed) to the static pressure from the static port. Changes in static pressure influence the indicated airspeed, making it essential that this instrument is properly calibrated and functioning correctly.

In summary, all three of these instruments respond to changes in static pressure, which is vital for accurate altitude measurement, rate of ascent or descent, and airspeed determination.