This forum discussion touches on a question that sits at the heart of crew resource management and FAA enforcement policy: when something goes wrong in a two-pilot cockpit, who actually bears the regulatory consequences? The original poster's question—whether both pilots on a crew are exposed to violation action when a "possible pilot deviation" (PPD) phone number is issued, or whether liability attaches only to whoever physically caused the event—reflects a genuine gray area that many working pilots encounter only after they've already been handed that dreaded frequency change to "call this number after landing." The answer, rooted in 14 CFR Part 91 and FAA Order 8900.1 enforcement guidance, is that responsibility is not automatically shared. The FAA's enforcement process focuses on identifying which pilot's action or omission actually caused the regulatory violation. In many single-pilot-flying-duty scenarios (e.g., an altitude bust, a runway incursion, or a clearance deviation), the Pilot Flying is typically the one whose airmen certificate is scrutinized, since they were manipulating the controls or radios at the time of the event.
That said, the picture is more nuanced for the Pilot Monitoring, particularly the captain, because of the regulatory concept of "final authority" under 14 CFR 91.3. The captain is legally responsible for the safe conduct of the flight regardless of who is flying, which means that in cases involving inadequate crew coordination, failure to cross-check, or a breakdown in CRM, the FAA can and does pursue enforcement against both pilots simultaneously—especially in Part 121/135 operations where SOPs explicitly require monitoring, callouts, and cross-verification. If an FO busts an altitude and the CVR or ATC tapes show the captain never caught it or challenged it, both certificates can be on the table, with the captain potentially facing a "failure to ensure compliance" citation even without being the one who touched the autopilot. Conversely, if the deviation stems from an FO's unilateral action taken without opportunity for the captain to intervene, enforcement may fall solely on the FO.
For working pilots, this matters enormously beyond the abstract regulatory question. It shapes how crews debrief incidents, what they say to company safety departments versus what they say to the FAA, and whether they engage union or ALPA-provided legal counsel before any conversation with an inspector. Most professional pilots are trained to remember that a phone number handed off by ATC is not itself a violation—it's an invitation to discuss what happened, and anything said can become part of an FAA investigation. The wise move, reinforced constantly in professional pilot circles including ALPA safety bulletins and legal-defense-plan guidance, is to politely decline detailed discussion until consulting an aviation attorney, since NASA ASRS reports (which can provide immunity from certificate action, though not necessarily protect against underlying facts) have strict 10-day filing windows that both crewmembers should independently consider filing regardless of who was flying.
More broadly, this thread reflects the ongoing tension in aviation safety culture between individual accountability and crew-based responsibility—a tension that has shaped decades of CRM doctrine since the 1970s shift away from strict captain-centric blame models. Airlines and the FAA have increasingly embraced Just Culture principles, which distinguish between honest errors, at-risk behavior, and reckless conduct, influencing whether enforcement is pursued at all versus handled through remedial training under programs like the FAA's Compliance Program or ASAP. For business jet and Part 91/135 operators without the same institutional safety-reporting infrastructure as major airlines, this question carries extra weight, since smaller flight departments may lack in-house legal support or established ASAP-equivalent programs, leaving individual pilots more exposed and more reliant on personal knowledge of their rights, their union or association resources, and the practical wisdom shared in exactly these kinds of peer discussions.