1. What is Pressure Altitude?

Pressure altitude is the altitude in the standard atmosphere where the pressure equals the measured pressure. It's a crucial concept in aviation for aircraft performance calculations and flight planning.

2. How Does the Calculator Work?

The calculator uses the pressure altitude formula:

Where:

• \( PA \) — Pressure altitude (ft)
• \( h \) — Indicated altitude (ft)
• \( P_0 \) — Standard pressure (29.92 inHg)
• \( P \) — Actual pressure (inHg)
• 0.00356 — Pressure lapse rate constant

Explanation: The formula adjusts the indicated altitude based on the difference between standard pressure and actual atmospheric pressure.

3. Importance of Pressure Altitude Calculation

Details: Pressure altitude is essential for determining aircraft performance characteristics including takeoff and landing distances, rate of climb, and true airspeed calculations.

4. Using the Calculator

Tips: Enter indicated altitude in feet, standard pressure (typically 29.92 inHg), and actual measured pressure in inches of mercury. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is pressure altitude important in aviation?
A: Pressure altitude provides a standardized reference for aircraft performance calculations regardless of actual atmospheric conditions.

Q2: What is the standard pressure value?
A: The standard atmospheric pressure at sea level is 29.92 inches of mercury (inHg) or 1013.25 hectopascals (hPa).

Q3: How does pressure affect aircraft performance?
A: Lower pressure (higher pressure altitude) reduces air density, which decreases engine power, propeller efficiency, and wing lift.

Q4: When is pressure altitude equal to indicated altitude?
A: When the actual atmospheric pressure equals the standard pressure of 29.92 inHg.

Q5: How does temperature affect pressure altitude calculations?
A: While this formula doesn't directly account for temperature, in practice, temperature variations affect air density and thus true altitude calculations.