What is the main function of a PIREP?

The main function of a PIREP, or pilot report, is to report current weather and flight conditions experienced by pilots during their flights. This information is crucial for other pilots, air traffic control, and meteorologists as it provides real-time observations from the cockpit about the weather, such as turbulence, cloud cover, visibility, and other atmospheric conditions. These reports help ensure the safety of flight operations and assist in decision-making for both air traffic controllers and pilots.

In contrast, the other options focus on different aspects of aviation reports. Informing about weather conditions at airports typically falls under the categories of METARs and TAFs rather than PIREPs, while forecasts for the next 24 hours are directly related to modeled predictions and not the real-time data that PIREPs provide. Documenting incidents of turbulence is a specific detail that can be included in a PIREP, but it does not encompass the broader purpose of reporting overall current weather and flight conditions.