Airspace and Weather Minimums Practice Test 2026 – Complete Exam Prep

In Class B airspace (including the 30 miles surrounding the primary airport), ATC relies on surveillance that includes your aircraft’s identity and altitude. To support that, you must have an operable transponder capable of encoding altitude (Mode C). The typical way this is described is a 4096-code transponder with Mode C altitude reporting. This allows ATC radar to see both who you are and how high you’re flying, which is essential for safe separation in busy airspace.

GPS with WAAS, a VOR receiver, or a marker beacon receiver aren’t required minimum equipment for this specific requirement. They may be useful in other contexts, but they do not fulfill the surveillance-altitude reporting need mandated for Class B. (Also, note that two-way radio communication with ATC is required to enter Class B, but that’s separate from this equipment requirement.)