FAA Military Competency Practice Exam

If an ATC transponder is installed in an aircraft that has not been tested as required, what is the limitation on its use?

1. Use is permitted with restrictions

2. It may be tested in-flight

3. Its use is not permitted

4. Its use is allowed under specified conditions

The correct answer is: Its use is not permitted

The limitation on the use of an ATC transponder that has not been tested as required is that its use is not permitted. This is crucial because an untested transponder may not operate correctly or provide accurate data to air traffic control (ATC). The reliability of radar data is essential for maintaining safe separation between aircraft and ensuring effective communication with ATC. If an aircraft's transponder does not meet regulatory testing standards, it may fail to transmit the necessary information such as altitude and identification, potentially compromising safety in the airspace system. Therefore, regulations strictly prohibit the use of any aircraft equipment, including transponders, that has not undergone the required testing to ensure operational integrity and compliance with safety protocols. Thus, requiring that a transponder be tested before use helps maintain high standards of safety within the aviation environment.