In which scenario is airborne thunderstorm detection equipment required?

The correct choice addresses the requirement for airborne thunderstorm detection equipment specifically for small aircraft that have a passenger seating configuration of 10 seats or more, excluding the pilot seat. This regulation is pertinent due to the increased risk posed by thunderstorms, which can significantly affect flight safety, particularly for smaller aircraft. These aircraft could be more vulnerable to turbulent weather conditions, and having operational thunderstorm detection equipment allows pilots to better navigate around hazardous weather.

The inclusion of passenger seating configuration ensures that safety measures are mandated for aircraft that are more likely to carry passengers rather than just cargo, highlighting a focus on passenger safety in aviation regulations. Such equipment is critical for enhancing situational awareness during flight by providing real-time data on thunderstorm activity, which can help prevent encounters with severe turbulence, lightning, and other related hazards.