US-FAA14 CFR 91.225
Automatic Dependent Surveillance-Broadcast (ADS-B) Out equipment and use
Read the official ruleIn plain English
ADS-B Out is required to operate in most of the same airspace that requires a Mode C transponder: Class A, B and C; within and above Class B and C; above 10,000 ft MSL (excluding below 2,500 ft AGL); and within the Mode C veil. It broadcasts your position to ATC and to other aircraft.
Key points
- Required in/above Class B and C, in Class A, and at/above 10,000 ft MSL (with the 2,500-AGL exception).
- Required within the 30 NM Mode C veil.
- Pairs with the transponder rule in 91.215.
Common pitfalls
- Assuming a transponder alone is sufficient where ADS-B Out is required.
*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation.*
This is an original plain-English explanation for training and reference, not legal advice and not for navigation. Always rely on the current official rule linked above. Last reviewed June 7, 2026.