Instrument Rating Checkride Practice Test

When is a Mode C transponder required on an aircraft?

1. Class B airspace only

2. Class A, B, C airspace

3. Only during night flights

4. Any flight above 5000 feet

The correct answer is: Class A, B, C airspace

A Mode C transponder is required in specific airspace to enhance safety and communication with Air Traffic Control. In particular, it must be operational in Class A, B, and C airspace. Class A airspace typically requires a Mode C transponder because it is primarily where IFR (Instrument Flight Rules) operations are conducted at high altitudes. Class B airspace surrounds busy airports, and the transponder helps ATC communicate with and track aircraft more effectively, thus preventing accidents. Class C airspace also demands a Mode C transponder since it includes controlled airports with significant traffic but lower levels of congestion than Class B. While a Mode C transponder has specific requirements for various airspaces, it is not limited to just Class B airspace or solely relevant for night flights. Additionally, the requirement of having a transponder only for flights above 5,000 feet is inaccurate, as the transponder is necessary in the aforementioned classes of airspace regardless of altitude. Therefore, having a Mode C transponder is vital for ensuring situational awareness among pilots and air traffic controllers in these controlled environments.