Runway lead-in lights (RLLS) at JFK's RNAV Z RWY 13L raise a precise but operationally consequential regulatory question under 14 CFR 91.175: whether RLLS qualify as an "approach light system" for purposes of the 100-foot-above-TDZE descent provision. The short answer is no. RLLS are a distinct category of visual aid, separate from the Approach Lighting Systems (ALS) enumerated and recognized by the FAA under 91.175(c)(3)(i). That subsection grants pilots the specific privilege of descending below the decision altitude or MDA to 100 feet above touchdown zone elevation using only the ALS as the visible runway environment reference — but only when that system is a recognized ALS type (ALSF-1/2, MALSR, MALSF, SSALR, SSALF, ODALS, RAIL, or similar). A pilot who acquires only the RLLS and nothing else from the runway environment has not satisfied the legal conditions necessary to continue the descent below DA/MDA.
RLLS exist to solve a specific visual guidance problem: approaches where the final approach course is laterally offset from the runway centerline, requiring a visual segment during which the pilot maneuvers to align with the runway. At JFK, the RNAV Z designation on 13L reflects a procedure design distinct from the "Y" variant, frequently involving higher minimums, a different final approach fix geometry, or a visual transition segment that does not track the runway extended centerline. The RLLS — a series of sequentially flashing lights — are installed to guide the pilot through that visual segment, bridging the gap between where instrument guidance ends and where the runway environment becomes clearly identifiable. They are depicted on approach charts and referenced in FAA Order 8260.3 (TERPS) documentation, but their function is navigational guidance, not lighting system classification under the approach lighting category definitions.
The practical regulatory framework under 91.175(c)(3) requires that at least one of a specific list of visual references be "distinctly visible and identifiable" before a pilot may descend below the authorized minimums and continue to a landing. The ALS is the only item on that list that allows descent to 100 feet above TDZE without seeing the actual runway environment (threshold, runway lights, touchdown zone, REIL, VASI, etc.). All other items on the list — when seen — authorize the full descent to landing. RLLS appear on none of these lists. Accordingly, a pilot on the RNAV Z 13L who acquires the first set of RLLS but not the runway, threshold, threshold lights, REIL, or another qualifying reference must execute a missed approach at or before DA. Continuing the descent on RLLS alone would constitute a violation of 91.175 regardless of the pilot's confidence in the visual segment ahead.
This distinction carries heightened importance for Part 121 and 135 operators flying into Class B environments like JFK, where approach complexity is elevated and procedural compliance is subject to close scrutiny. Flight departments operating under Part 91K or corporate Part 135 certificates must ensure their crews are briefed specifically on which visual aids at a given airport qualify for 91.175 purposes, particularly at airports where offset approaches with RLLS exist alongside more conventional straight-in procedures. The "Z" approach designation itself signals additional procedure complexity, and the presence of RLLS should prompt crews to explicitly brief what the required visual references are, at what altitude they expect acquisition, and what the missed approach trigger point is — rather than treating any visible light sequence as authorization to continue.
The broader trend underlying this question reflects the increasing complexity of RNAV and RNP approach procedures at major airports, where curved path segments, offset finals, and visual transition requirements are becoming more common as airport capacity demands and obstacle environments push designers away from conventional straight-in geometries. RLLS installations are expanding at airports where traditional ALS cannot provide adequate guidance through offset visual segments, and as more crews encounter these procedures the potential for regulatory misunderstanding grows. The FAA's TERPS standards and 91.175 were written primarily around conventional ILS and straight-in approach architecture; crews operating at airports with nonstandard visual segment designs bear responsibility for understanding exactly which ground-based aids carry legal authorization weight and which do not.