What is a requirement to fly single pilot IFR in an air taxi?

To fly single pilot IFR in an air taxi, having a PPC (Pilot Proficiency Check) is a crucial requirement. The PPC is a specific assessment that evaluates the pilot's ability to operate the aircraft under instrument flight rules, ensuring they possess the necessary skills and knowledge to handle both routine operations and unexpected situations in an IFR context. It demonstrates that the pilot has undergone rigorous training and has been deemed proficient by an authorized instructor or examiner, which is essential for safety in commercial operations.

The other options, while they may pertain to general qualifications or experience levels, do not specifically address the unique proficiency standards required for single pilot IFR operations in an air taxi. Having a certain amount of flight time may be important for overall competency, but it does not substitute for the targeted training and evaluation provided by the PPC. This emphasizes the importance of specialized training and assessment in maintaining safety and operational standards in aviation.