The regulatory disconnect between Part 121/135 instrument currency and Part 91 personal flying represents a genuine structural inconsistency in 14 CFR 61.57 that affects a significant number of professional pilots. Under 61.57(c), any pilot acting as PIC under IFR must have logged, within the preceding six calendar months, six instrument approaches, holding procedures, and intercepting/tracking tasks in the appropriate aircraft category. Under 61.57(e), pilots operating under Part 121 or 135 may use instrument checks and approaches logged in those operations to satisfy the Part 91 currency requirements — but only prospectively, once currency is already intact. If a pilot has allowed the six-month window to lapse entirely, the 121/135 exception does not restore currency; an Instrument Proficiency Check (IPC) administered by a CFII or check airman is required before that pilot can legally act as PIC in IMC or under IFR in their personally owned aircraft, regardless of how many ILS approaches they flew the week prior in a Boeing or Challenger.
The contrast with the flight review regulation under 61.56 is substantively valid and highlights a philosophical inconsistency in how the FAA treats professional check events. Under 61.56(b), a pilot who completes a Part 121 or 135 proficiency check is flatly not required to complete a flight review — the professional check serves as a complete substitute irrespective of where the pilot is in their BFR cycle. No analogous clean exemption exists for instrument currency once lapse has occurred. The IPC, while procedurally straightforward for an experienced professional pilot, still requires scheduling, an available CFII, and a capable aircraft or approved simulator, creating a legitimate administrative burden for pilots who are demonstrably proficient in far more demanding operational environments.
For working Part 121 and 135 pilots who own or share GA aircraft — a large demographic within the professional pilot community — this regulatory gap has practical consequences. A regional first officer flying 75 hours of IFR per month into Class C airports may find themselves technically unable to file IFR in their personal Cessna because they missed the six-calendar-month window without logging approaches specifically in a single-engine general aviation context. The category and class nuance compounds the issue: currency logged in a transport-category aircraft does not automatically satisfy currency requirements for a single-engine piston unless the 61.57(e) prospective maintenance provision is actively being used. Operators and pilots in the Part 91K and 135 fractional space encounter similar friction when personnel transitions or scheduling gaps interrupt the currency chain for personal aircraft operations.
The broader regulatory question the original post raises is whether the FAA's currency framework, designed to ensure recency of experience, is being applied in a manner proportionate to demonstrated competency. The IPC itself is not an unreasonable safety gate for a truly lapsed pilot, but its application to a line pilot actively flying IFR professionally raises legitimate questions about regulatory coherence. Several aviation legal scholars and AOPA have previously noted that 61.57's structure was drafted before the modern proliferation of professional pilots who maintain robust personal GA fleets, and the asymmetry between the BFR and IFR currency treatment of professional checks is an area where a regulatory revision or at minimum an NPRM clarification would serve the pilot community more logically. Until such revision occurs, professional pilots maintaining personal IFR operations must actively manage the 61.57(c) calendar window as a separate administrative obligation from their professional currency requirements.