A recently instrument-rated pilot's candid Reddit post has surfaced a scenario that exposes one of the more insidious traps in practical IFR flying: the back-to-back approach to the same runway with different minimums. The pilot flew an ILS followed immediately by a LOC to the same runway and runway end, then an RNAV at a second airport. On the LOC, the pilot verbally briefed the correct MDA of 1,900 feet but inadvertently left the altimeter bug set to 1,700 feet — the DA from the preceding ILS. The result was a descent approximately 150 feet below MDA, flown at that altitude from the VDP to the MAP. The DPE acknowledged the error in debrief, attributed it partly to his own in-flight conversation about VDPs, and allowed the pass to stand. The pilot passed the checkride, received the certificate, and is now wrestling publicly with whether the outcome was deserved.
From a regulatory and standards standpoint, the deviation described is unambiguous. The FAA Instrument Rating Airman Certification Standards (ACS) designates adherence to applicable minimums as a critical task — one of only a handful of items for which a single unsatisfactory performance is disqualifying regardless of all other performance. Descending 150 feet below MDA, without the required visual references for a traditional non-precision approach, meets the definition of a critical task failure. The DPE's decision to pass the applicant will likely generate debate among instructors and evaluators, and the pilot's discomfort with the outcome reflects a healthy internalization of the underlying safety principle even when the formal system did not enforce it. The pilot is correct that perfection is not the standard, but minimum altitude integrity on an instrument approach is not a performance tolerance — it is a hard floor with no acceptable deviation absent visual contact with the required references.
The specific mechanism of the error is instructive for any IFR pilot flying sequential approaches. When an ILS and LOC serve the same runway, the ILS DA will typically be lower than the LOC MDA by a significant margin, because the ILS provides precision vertical guidance while the LOC does not. In this case, the difference was 200 feet. Resetting minimums bugs between approaches in the same sequence — particularly when the approaches share a runway, an airport identifier, and much of their geography — requires deliberate procedural discipline because the visual and cognitive context is nearly identical. The habit of briefing minimums aloud, which the pilot did perform, is necessary but not sufficient; physical verification of the bug position against the briefed value is the confirming step that failed here. Many operators flying single-pilot IFR under Part 91 or 135 use a final-items scan at the final approach fix specifically to cross-check the bug against the plate, a practice this incident validates.
The DPE's in-flight commentary about VDPs adds a layer worth examining beyond the checkride context. The VDP — visual descent point — is a calculated position on a non-precision approach from which a normal descent from MDA can be initiated to reach the runway touchdown zone. Discussing it actively on final while the applicant was managing the approach almost certainly occupied working memory that would otherwise have been available for instrument cross-check and procedural verification. In operational flying, this dynamic maps directly to sterile cockpit discipline: task-irrelevant conversation during high-workload phases of flight, even from well-intentioned sources, degrades procedural performance. The DPE may have acknowledged this implicitly by attributing part of the error to his own distraction of the applicant, but the broader lesson — that cockpit conversation on final is a resource management issue, not merely an etiquette preference — applies equally to crew environments, check airmen conducting line checks, and passengers who engage flight crews during approach.
The pilot's discomfort with receiving a pass after a safety-significant deviation reflects a maturity that will likely serve well in operational flying. The instrument rating is the gateway credential for IFR currency and single-pilot operations in IMC, and the habits formed around minimum altitude discipline establish the baseline from which all subsequent IFR experience compounds. The error made — bugging the wrong minimums during a high-distraction back-to-back approach sequence — is not exotic; it is a known human factors trap documented in accident and incident records involving far more experienced pilots. The difference between the student's outcome and a more serious consequence was terrain clearance margin, benign conditions, and a DPE who happened to be monitoring. In operational IFR, those margins cannot be assumed, and the pilot who internalizes this incident as a permanent trigger for deliberate minimums verification has arguably gained something more durable than a clean checkride record.