Comedian, showrunner, and pilot Nathan Fielder has become embroiled in a dispute with the Federal Aviation Administration over his show’s hypothesis that poor communication between pilots and co-pilots causes plane crashes.

The second season of Fielder’s HBO comedy The Rehearsal concluded on Sunday, generating a tremendous amount of buzz over the real-world applications of his experiment. The show focuses on Fielder’s attempts to help others with difficult life decisions by creating meticulous, elaborate “rehearsals,” replete with detailed sets and actors, allowing the subjects to practice making the decision. For the second season, Fielder expanded a rehearsal testing an airline first officer’s assertiveness into a broader test regarding pilot communication.