What instrument serves as a backup to the altitude indication found on the primary flight display?

• A. Standby Altimeter
• B. Attitude Indicator
• C. Heading Indicator
• D. Vertical Speed Indicator

Answer: (A)

The standby altimeter functions as a backup to the altitude indication found on the primary flight display. In an aircraft, the primary flight display shows critical flight information, including altitude, but should that instrument fail or provide incorrect data due to a malfunction, the standby altimeter serves as a redundant source of altitude information.

The standby altimeter typically operates independently of the primary flight display system and is designed to be quick and easy to read. It allows pilots to maintain an accurate awareness of their altitude, which is crucial for maintaining safe flight operations, especially when flying in controlled airspace or during instrument flight.

While other instruments like the attitude indicator, heading indicator, and vertical speed indicator provide valuable flight information, they do not serve the same purpose as the standby altimeter. The attitude indicator shows the aircraft's orientation relative to the horizon, the heading indicator indicates the direction the aircraft is facing, and the vertical speed indicator displays the rate of climb or descent rather than absolute altitude.