Comprehensive Aviation Regulation, Licensing, and Airspace Management Practice Test 2026 - Free Practice Questions and Study Guide

The key idea is that within the Mode C veil around Class B airports, the requirement is for an altitude-reporting transponder (Mode C) to be installed and capable. Altitude information is provided automatically by the transponder in response to ATC interrogations, not by the pilot’s voice reporting. So the rule isn’t asking you to verbally report your altitude; it’s asking you to have the equipment that automatically conveys altitude to ATC. This capability is required within roughly 30 nautical miles of the primary Class B airport, regardless of your altitude.