PAPI Lights

PAPI lights, which stands for Precision Approach Path Indicator lights, are a system of lights found at many airports to assist pilots during the approach phase of landing an aircraft. The primary purpose of PAPI lights is to provide visual guidance to pilots to ensure they are following the correct glide path for a safe landing. Here’s how they work:

1. **Color Configuration**: PAPI lights typically consist of a series of lights arranged in a row or line, usually next to the runway. These lights are typically color-coded. A standard PAPI system uses four lights, with two on the left side and two on the right side of the runway. The color configuration is typically as follows:
– **Red**: If a pilot sees all four lights as red, it indicates that they are too low and need to increase their altitude.
– **White**: If a pilot sees all four lights as white, it indicates that they are too high and need to descend.
– **Combination of Red and White**: When a pilot sees a combination of red and white lights, it signifies that they are on the correct glide path, ensuring a safe approach angle for landing.

2. **Angle of Descent**: The angle of descent that PAPI lights guide pilots to follow is typically around 3 degrees, which is considered to be a standard approach angle for many runways. This angle ensures that the aircraft is on a proper descent path for landing.

3. **Visibility**: PAPI lights are especially useful during low-visibility conditions, such as fog or heavy rain, as they provide a clear visual reference for pilots to maintain the correct approach path.

4. **Placement**: PAPI lights are usually installed on the left side of the runway. Pilots can easily see and interpret the color of the lights from their perspective as they approach the runway. This positioning allows pilots to make real-time adjustments to their altitude and descent rate to ensure a safe landing.

In summary, PAPI lights are a valuable aid for pilots during the critical phase of landing an aircraft. They help ensure that the aircraft approaches the runway at the correct angle and altitude, increasing safety, especially in adverse weather conditions.