PAPI Calculator

PAPI Glide Slope Formula:

\[ \text{Angle} = \arctan\left(\frac{\text{Height}}{\text{Distance}}\right) \]

Angle:

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1. What is PAPI?

PAPI (Precision Approach Path Indicator) is a visual aid that provides guidance information to help a pilot acquire and maintain the correct approach (glide slope) to an airport runway. It uses light units to show the pilot whether they are too high, too low, or on the correct glide path.

2. How Does the Calculator Work?

The calculator uses the arctangent formula:

\[ \text{Angle} = \arctan\left(\frac{\text{Height}}{\text{Distance}}\right) \]

Where:

\( \text{Height} \) — Vertical height in feet
\( \text{Distance} \) — Horizontal distance in feet
\( \arctan \) — Inverse tangent function

Explanation: The formula calculates the glide slope angle based on the ratio of height to distance, which is essential for proper aircraft approach.

3. Importance of PAPI Calculation

Details: Accurate glide slope calculation is crucial for safe aircraft approach and landing. It helps pilots maintain the correct descent angle to avoid obstacles and ensure a smooth touchdown at the intended point on the runway.

4. Using the Calculator

Tips: Enter height and distance values in feet. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the standard PAPI glide slope angle?
A: The standard PAPI glide slope is typically 3 degrees, though it can vary between 2.5-3.5 degrees depending on airport requirements.

Q2: How does PAPI help pilots during approach?
A: PAPI lights show red and white indications: four white lights means too high, two red/two white means on glide path, four red lights means too low.

Q3: What factors can affect PAPI accuracy?
A: Weather conditions, aircraft type, pilot perspective, and proper installation/maintenance of the PAPI system can all affect accuracy.

Q4: Is PAPI used at all airports?
A: PAPI is commonly used at most airports, but smaller airports might use simpler visual approach aids or rely on instrument approaches.

Q5: Can this calculator be used for other glide slope applications?
A: Yes, the same trigonometric principle applies to any situation where you need to calculate an angle from height and distance measurements.