Enter the total number of in or mm of mercury (or millibars) into the calculator. The calculator will display the equivalent pressure altitude in ft or meters.
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Pressure Altitude Formula
The following formula is used to convert mercury into altitude feet.
h(alt) = ( 1 – ( P / 1013.25) ^ .190284) * 145366.45
- Where h(alt) is the altitude pressure (ft)
- P is the measured pressure
Pressure Altitude Definition
Pressure altitude is a crucial concept for pilots and aviation enthusiasts as it provides a standardized reference point for measuring and comparing altitudes. It is a term used to describe the altitude of an aircraft above a specific pressure level rather than the distance above sea level.
Atmospheric pressure decreases as altitude increases, which affects the performance of aircraft and their systems. Pressure altitude is determined by calibrating the aircraft’s altimeter to a standard atmospheric pressure setting, typically 29.92 inches of mercury (inHg), known as the standard datum plane.
By using pressure altitude, pilots can assess their position relative to this standard reference level, regardless of variations in local atmospheric pressure.
Pressure Altitude Example
How to calculate altitude pressure
- First, measure the station pressure.
This station pressure will normally be measured in mm or inches of mercury.
- Next, convert to pressure.
Convert the pressure from mm or in of mercury to millibars.
- Calculate the altitude pressure.
Using the pressure from step 2, calculate the pressure altitude using the formula above.
FAQ
Why is pressure altitude important in aviation?
Pressure altitude is crucial in aviation because it allows pilots to ensure that their aircraft is flying at a safe altitude, especially when flying over mountainous terrain or in turbulent weather conditions. It also helps in optimizing the aircraft’s performance by adjusting engine settings and flight paths according to the standardized pressure levels.
How does atmospheric pressure affect aircraft performance?
Atmospheric pressure affects aircraft performance in several ways. As altitude increases and atmospheric pressure decreases, the air becomes less dense. This reduces the amount of lift generated by the wings, the efficiency of the engines, and the effectiveness of the control surfaces. Pilots must adjust their flight operations accordingly to maintain safe and efficient flight.
Can pressure altitude be used for navigation?
Yes, pressure altitude can be used for navigation, particularly in high-altitude flight operations. It provides a standardized reference that pilots can use to compare altitudes and ensure vertical separation from other aircraft, terrain, and obstacles. However, it is typically used in conjunction with other navigation tools and methods for precise location and pathfinding.
