FAA Ground School Practice Test

How should a pilot react if they see a red light on a Precision Approach Path Indicator?

1. Maintain altitude

2. Increase altitude

3. Initiate a go-around

4. Descend to the glide slope

The correct answer is: Increase altitude

If a pilot sees a red light on a Precision Approach Path Indicator (PAPI), it signifies that they are below the ideal glide slope for landing. The correct reaction to this indication is to increase altitude, which corresponds to the appropriate choice in this scenario. The PAPI works by providing visual cues to help pilots maintain the correct approach angle to the runway during landing. A red light indicates that the aircraft is too low, while a white light would indicate that the aircraft is too high. To remedy the situation indicated by the red light, the pilot must adjust their altitude by increasing it until they are back on the proper glide slope. This action helps ensure a safe approach and landing, preventing any potential hazards associated with being too low, such as obstacles or a hard landing. Maintaining altitude or initiating a go-around would not address the immediate issue of being below the glide slope and could lead to complications. Descending further, when already too low, would be incorrect as well. Therefore, the most appropriate action in response to a red light on a PAPI is to increase altitude to return to the correct glide path.