Within 30 miles of a Class B primary airport, from the surface up to 10,000 feet MSL, aircraft must be equipped with what transponder capability?

Within 30 miles of a Class B primary airport, from the surface up to 10,000 feet MSL, aircraft must be equipped with what transponder capability?

• A. An operable transponder with Mode S or 4096 code capability with Mode C altitude reporting
• B. A basic transponder
• C. No transponder requirement
• D. An encoding altimeter only

Answer: (A)

Altitude information from your transponder is required in this part of Class B airspace. Within 30 miles of a Class B primary airport, from the surface up to 10,000 feet MSL, an aircraft must have an operable transponder that can report altitude. That means the transponder should either be a Mode S transponder or a transponder capable of 4096 code (Mode A) in combination with Mode C altitude reporting. The altitude readout helps ATC separate aircraft vertically, and Mode S offers additional capabilities beyond basic altitude reporting. A basic transponder without altitude reporting won’t satisfy this requirement, and an encoding altimeter alone isn’t a transponder capability.

Altitude information from your transponder is required in this part of Class B airspace. Within 30 miles of a Class B primary airport, from the surface up to 10,000 feet MSL, an aircraft must have an operable transponder that can report altitude. That means the transponder should either be a Mode S transponder or a transponder capable of 4096 code (Mode A) in combination with Mode C altitude reporting. The altitude readout helps ATC separate aircraft vertically, and Mode S offers additional capabilities beyond basic altitude reporting. A basic transponder without altitude reporting won’t satisfy this requirement, and an encoding altimeter alone isn’t a transponder capability.