How are altimeter settings measured?

Altimeter settings are critical for aviation as they determine the altitude at which an aircraft is flying in relation to sea level. The correct answer indicates that altimeter settings are measured in inches of mercury (inHg) or hectopascals (hPa).

The altimeter is a device that measures air pressure, which decreases with altitude. By referencing standard atmospheric pressure at sea level (29.92 inches of mercury or 1013.25 hPa), pilots can calibrate the altimeter to ensure they know their actual altitude in relation to the ground and surrounding terrain. When an altimeter is set to the local altimeter setting, which is given in these units, it allows pilots to maintain safe altitudes while flying.

The mention of inches of mercury and hectopascals reflects the units commonly used in aviation for altimeter settings. These measurements provide vital information for maintaining proper altitude and ensuring flight safety, especially when flying at low altitudes or in mountainous regions.

Other choices involve measurements not relevant to altimeter settings. For example, feet of elevation might relate to the height of an area above sea level, but it does not reflect how those heights are determined or calibrated in aviation. Cubic feet per minute is a volumetric flow rate