What altitude is indicated on the altimeter based on the described scenario?

The indicated altitude on the altimeter is based on the specific atmospheric pressure setting that the altimeter is calibrated to recognize. In many scenarios, it is essential to understand how the altimeter works in conjunction with the local pressure settings to derive an accurate reading.

In this case, if B indicates 4,790 feet MSL, this could suggest that the altimeter has been calibrated correctly to the local barometric pressure, providing an accurate representation of the aircraft's altitude above mean sea level (MSL). The actual reading would have been aligned with a correctly set altimeter that corresponds to the existing atmospheric conditions.

Understanding how altimeters function is crucial for pilots, especially in instrument flight rules (IFR) operations. It allows them to maintain altitude awareness, manage vertical navigation appropriately, and ensure safe separation from terrain and other aircraft. This context confirms that the indicated altitude must reflect an accurate reading influenced by current pressure settings provided either through local altimeter readings or standard atmospheric pressure references.