Altimeter Setting

Definition

The altimeter setting is the barometric pressure adjusted to sea level, which pilots use to calibrate their altimeters for accurate altitude readings. This setting is crucial for flight safety as it ensures that the aircraft maintains the correct altitude in relation to the terrain and other aircraft. The altimeter setting is determined from atmospheric pressure measurements and is expressed in inches of mercury (inHg) or hectopascals (hPa).

5 Must Know Facts For Your Next Test

1. Altimeter settings are updated regularly to account for changes in atmospheric pressure, which can affect altitude readings.
2. Pilots typically receive the altimeter setting from air traffic control before takeoff and during flight to ensure accurate altitude maintenance.
3. In regions with rapidly changing weather conditions, altimeter settings can change frequently, requiring pilots to be vigilant.
4. Using an incorrect altimeter setting can lead to altitude deviations, increasing the risk of mid-air collisions or terrain impacts.
5. When transitioning between different pressure systems, pilots must adjust their altimeters accordingly to reflect the local pressure conditions.

Review Questions

• How does the altimeter setting influence flight safety and navigation during a flight?
  • The altimeter setting plays a crucial role in flight safety and navigation by providing pilots with accurate altitude information relative to sea level. When the altimeter is correctly set, it helps maintain safe separation from terrain and other aircraft. Incorrect settings can lead to altitude miscalculations, potentially resulting in hazardous situations such as controlled flight into terrain or mid-air collisions.
• Discuss the process by which pilots obtain and use altimeter settings during different phases of flight.
  • Pilots typically obtain altimeter settings from air traffic control or automated weather stations before departure and during flight. They adjust their altimeters based on this information to ensure accurate altitude readings. During climb, descent, and level flight, pilots must continually monitor and adjust the altimeter for changing atmospheric pressures to maintain appropriate altitude levels relative to the surrounding environment.
• Evaluate the implications of not adjusting altimeter settings when flying through varying pressure systems on overall flight operations.
  • Failing to adjust altimeter settings when flying through varying pressure systems can have serious implications for overall flight operations. It can lead to significant altitude discrepancies, creating a risk of collisions with terrain or other aircraft. Additionally, this oversight can complicate air traffic management, as incorrect altitude readings may interfere with separation protocols, resulting in inefficient airspace usage and increased operational risks for both pilots and air traffic controllers.

Related terms

Barometer: An instrument used to measure atmospheric pressure, which is essential for determining the altimeter setting.

Pressure Altitude:

The altitude indicated by an altimeter when it is set to 29.92 inHg (standard pressure), used for calculating flight levels.

QNH: A term that refers to the altimeter setting that indicates the actual barometric pressure at a specific location adjusted to sea level.