How often should the indicated height be reset when using the aircraft-type altimeter?

The indicated height should be reset each time the altimeter setting is determined to ensure accuracy in altitude readings. This practice is essential because atmospheric pressure changes due to weather conditions and temperature can significantly affect altitude measurements. When pilots receive updated altimeter settings from air traffic control or when entering different weather systems, resetting the altimeter helps maintain precise altitude awareness, which is crucial for safe flight operations.

Furthermore, frequent resetting in response to new altimeter settings allows for adjustments that account for changes in pressure conditions at sea level, which can vary with shifts in weather. This standard operating procedure contributes to more reliable altitude data, ultimately enhancing safety in aviation operations.