How is altitude information typically indicated on an altitude indicator?

• A. Through GPS satellite data
• B. Using vertical speed indicators
• C. By barometric pressure readings
• D. Through radar signals

Answer: (C)

Altitude information on an altitude indicator is typically indicated by barometric pressure readings. Altitude indicators, commonly referred to as altimeters, operate on the principle of measuring changes in air pressure. As an aircraft ascends, the atmospheric pressure decreases. The altimeter converts this pressure change into an altitude reading, which is displayed to the pilot.

Barometric altimetry relies on the standard atmosphere model, which assumes that pressure decreases predictably with altitude. Pilots often set a reference pressure (known as the altimeter setting) to account for local variations in atmospheric pressure, ensuring that altitude readings are accurate relative to sea level.

Utilizing GPS satellite data can provide altitude information; however, it is generally not the primary means of displaying altitude on traditional cockpit instruments. Vertical speed indicators measure the rate of ascent or descent rather than the current altitude, and while radar can detect altitude indirectly, it is not used for providing altitude readings on an altitude indicator in the cockpit.