When the altimeter is set to 29.92" Hg, what altitude does it indicate?

When the altimeter is set to 29.92 inches of mercury (Hg), it indicates pressure altitude. This setting represents the standard atmospheric pressure at sea level, which allows the altimeter to measure altitude in terms of the atmospheric pressure rather than the actual height above sea level.

Pressure altitude is crucial in aviation, especially when flying at higher altitudes, as it is used for flight planning and maintaining safe vertical separation between aircraft. When an aircraft’s altimeter indicates pressure altitude, it assists pilots in navigating and ensuring safe operation in compliance with air traffic control instructions.

In a practical sense, when pilots adjust their altimeters to 29.92 Hg, they align their readings with a uniform standard, which facilitates consistent communication and altimeter settings across aircraft, especially in flight levels above the transition altitude where the standard pressure is consistently applied.