If an IMC flight is expected to encounter thunderstorms enroute, does the aircraft need to be equipped with a weather radar?

• A. Yes
• B. Yes, but only if thunderstorms are reported to have developed already
• C. No, unless it is part of the MEL
• D. No, if the cruise level is planned over FL410

Answer: (A)

Detecting and avoiding convective weather in instrument conditions hinges on having a forward-looking view of storms. Weather radar in the cockpit provides a real-time picture of precipitation and storm intensity, showing where cells are, how fast they’re moving, and where the bases and tops lie. This lets you plan a safe route around thunderstorms and choose altitudes with the best odds of clear air, which is essential when you’re flying in IMC and cannot see weather with the naked eye.

Storms can develop quickly, so radar is needed to detect developing activity, not just storms that have already been reported. Relying on forecasts or on equipment being permitted to be inoperative by MEL isn’t a substitute for having radar onboard when convective weather is anticipated enroute. And simply flying at a high cruise altitude does not remove weather risk, since thunderstorms can extend into higher levels and radar is the tool that helps you see and avoid them.