What is a common tool used for altitude verification during an approach?

The common tool used for altitude verification during an approach is the altimeter. An altimeter measures the aircraft's altitude above a reference point, typically the mean sea level. In instrument flight operations, accurate altitude readings are crucial for maintaining safe vertical separation from terrain and other aircraft, especially during the approach phase when precision is paramount.

The altimeter works by measuring the pressure of the surrounding air. As an aircraft climbs, the atmospheric pressure decreases; this change in pressure is translated into altitude. Pilots set the altimeter to the local altimeter setting, which ensures that altitude readings are consistent with those of air traffic control and other aircraft.

While GPS can provide altitude information, it is typically used for lateral navigation rather than precise altitude verification, making it less reliable for this specific purpose. VOR (VHF Omni-directional Range) is primarily used for navigation by providing bearing information but does not give altitude data. A barometer measures atmospheric pressure but is not commonly used directly by pilots for altitude verification; rather, it provides input for the operation of the altimeter.

The altimeter's role in the approach phase—coupled with proper pre-flight checks and in-flight adjustments—ensures that pilots maintain appropriate altitudes and adhere to the required vertical profiles