The question posed in this r/flying thread touches on a recurring gray area in FAA currency regulations: whether approaches flown in an airline's Level D full-flight simulator, accessed informally as a "guest ride" rather than through a structured Part 142 or Part 121/135 training curriculum, can be logged toward instrument currency under 14 CFR 61.57(c). The short answer, which experienced pilots in the thread reliably converge on, is no—not under the circumstances described. FAA regulations are explicit that to log instrument approaches, holds, and intercepting/tracking tasks toward the six-approaches-in-six-months requirement, the simulator must be an FAA-approved Aviation Training Device (ATD), Flight Training Device (FTD), or Full Flight Simulator (FFS) used under an approved course of training, typically within a Part 142 training center, a Part 61.4(c) letter of authorization, or as part of an air carrier's approved training program under Part 121/135. A one-off favor from a friend who works for an airline, done outside the certificated training curriculum and without an appropriately rated instructor or check airman signing for the session in accordance with the device's approved use, does not meet the letter of the regulation even though the simulator itself is FAA-qualified hardware.
This distinction matters immensely to working pilots because logbook entries are legal records, and currency claims get scrutinized closely during checkrides, insurance audits, 709 rides, or post-incident investigations. An airline-grade Level D simulator is unquestionably higher fidelity than most GA-accessible ATDs, which makes the temptation to log time in one understandable—pilots reasonably assume "better equipment" should count for at least as much as a Redbird or a basic FTD. But the FAA's currency framework isn't about simulator fidelity alone; it's about the surrounding training infrastructure: an approved course, oversight by an authorized instructor, and use within the parameters of that facility's training specifications. A guest sim session, however professionally run, generally lacks these structural elements, which means logging those approaches toward 61.57(c) currency would create a logbook entry that doesn't survive regulatory scrutiny even if it was educational and confidence-building.
For corporate, charter, and airline pilots, this scenario is a useful reminder of a broader principle: access to sophisticated equipment doesn't automatically confer loggability. The same logic applies to jumpseat riders logging PIC time in the right seat of an airliner, or pilots logging multi-engine time in a simulator without the proper training center agreement. Part 135 and Part 91K operators in particular should be attentive to this because their pilots often move between operators with different simulator vendors (FlightSafety, CAE, TRU) and training specifications, and currency lapses discovered mid-audit can ground a pilot or delay a charter dispatch. Documentation discipline—knowing exactly which device, which course, and which authorization applies—is not bureaucratic pedantry; it's what keeps a 6-month instrument currency claim defensible.
More broadly, this thread reflects a persistent tension in the pilot community between practical skill-building and regulatory compliance. Many pilots in the replies likely encouraged the original poster to take the sim ride anyway purely for proficiency and familiarization value, even while agreeing it shouldn't be logged for currency. That's sound advice: flying approaches in a Level D sim is excellent stick-and-rudder and procedural practice regardless of its loggability, and many professional pilots use "bootleg" sim time this way. But the episode underscores why pilots—especially those building hours toward ATP mins or maintaining currency across multiple certificates—should treat FAA guidance letters, AC 61-136 (on ATDs), and their own training department's ops specs as the actual source of truth, rather than assuming any FAA-type-approved box automatically makes its output loggable.