Threshold, wing-bar and runway-end light quantity — ICAO / FAA — with a shared-fixture engine that keeps physical fixture count separate from functional count.
One physical fitting can perform both a threshold function and a runway-end function when the threshold sits at the runway extremity — this calculator counts that fitting once physically while still reporting two functions served. A displaced threshold breaks that sharing by default. This module reuses the same threshold/runway-end logic as Calculator #02 and does not recalculate runway edge-light spacing independently — see Calculator #01 for that.
Used only for ICAO CAT I/II/III threshold-light geometry below.
ICAO 5.3.11 permits fittings serving as threshold lights to also serve as runway-end lights when the threshold is at the runway extremity — this calculator applies the same logic under FAA/Project bases unless overridden.
Sets how many ends are counted: one direction counts one end, both counts two ends with the same configuration at each. If the two ends differ, for example only one threshold is displaced, run them separately. Also drives the colour reference below.
| Component | Quantity | Function |
|---|---|---|
| Threshold lights | — | Threshold |
| Wing-bar lights | — | Threshold |
| Runway-end lights | — | Runway end |
| Shared fixtures | — | Threshold + runway end |
| Physical fixtures (all ends counted) | — | Actual units |
Calculated / Nominal Quantity — not a Final BOQ Quantity. Physical fixture count and functional count are reported separately by design; do not add functions where a fixture serves more than one.
Standard convention only — the reverse direction may present differently; confirm against the approved layout.
| Direction | Threshold function | Runway-end function |
|---|
The central problem this calculator solves: one physical fitting can perform two functions. Adding threshold-light and runway-end-light counts without subtracting the overlap double-counts every shared fixture in a normal-threshold configuration.
Where QT = threshold lights, QW = wing-bar lights, QE = runway-end lights, QS = fixtures serving more than one function. The functional count (QT + QW + QE, without subtracting) is reported alongside the physical count — they are not the same number whenever sharing applies.
| Runway operation | Threshold-light requirement |
|---|---|
| Non-instrument / Non-precision | Min. 6 (displaced + wing-bar exception applies) |
| Precision CAT I | ≤ 3 m spacing (confirm arrangement in Annex 14) |
| Precision CAT II / III | ≤ 3 m uniform spacing |
| Runway type | Per side | Total |
|---|---|---|
| Visual runway | 3 | 6 |
| Instrument runway | 4 | 8 |
Minimum configuration quantities, not the entire runway lighting quantity. Where one end is visual and the other instrument, two groups of four are used at both ends. FAA's basic model does not vary by CAT I/II/III the way ICAO's does — a category-specific FAA threshold formula is not yet incorporated.
Displaced threshold, FAA instrument runway: QT=8, QE=8, QS=0 → Qphysical = 8+8−0 = 16.
Normal threshold, same fittings serve both functions: QT=8, QE=8, QS=8 → Qphysical = 8+8−8 = 8.
| 🟢 PASS | Installed quantity meets the calculated minimum |
| 🔴 FAIL | Installed quantity below the calculated minimum |
| 🟠 REVIEW | Precision-category geometry, displaced threshold, or project-specific arrangement — requires drawing review regardless of the number entered |
| ⚪ N/A | No installed quantity entered — compliance not checked |
Sharing is only applied automatically when the threshold sits at the runway extremity. A displaced threshold breaks the physical continuity between the threshold location and the runway extremity, so runway-end lighting becomes a separate geometric element by default — forcing sharing on a displaced threshold is treated as a non-standard, project-specific override and flagged accordingly.
This calculator does not recalculate runway edge-light spacing independently. Runway width and edge-light-row geometry feed the CAT I/II/III threshold calculation the same way as in Calculator #02 — for the edge-light quantity itself, use Calculator #01 / #02.
This calculator reports an installed fixture quantity, not a serviceability-adjusted count. Serviceability percentages belong in a separate AGL Serviceability Calculator, not multiplied into the quantity here.
Quick answers on threshold, wing-bar and runway-end quantities and the shared-fixture count.
It calculates the threshold, wing-bar and runway-end light quantity under ICAO or FAA rules, using a shared-fixture engine that keeps the physical fixture count separate from the functional count. It reports a quantity schedule and a build-up by function, checks an installed quantity, and produces a PDF report.
When the threshold is at the runway extremity, one physical fitting can perform both functions. ICAO 5.3.11 permits fittings that serve as threshold lights to also serve as runway-end lights in that case. Adding the threshold and runway-end counts without subtracting the overlap would double-count every shared fixture, so the calculator counts the fitting once physically while still reporting two functions served.
The general engine is Qphysical = QT + QW + QE − QS, where QT is threshold lights, QW wing-bar lights, QE runway-end lights and QS fixtures serving more than one function. The functional count QT + QW + QE is reported alongside it and is not the same number whenever sharing applies. For an FAA instrument runway, QT = 8, QE = 8 and QS = 0 with a displaced threshold gives 16, and QS = 8 with a normal threshold gives 8.
A displaced threshold breaks the physical continuity between the threshold and the runway extremity, so runway-end lighting becomes a separate element by default and sharing is not applied automatically. Forcing sharing on a displaced threshold is treated as a non-standard, project-specific override and is flagged. The runway-end quantity is entered per the approved layout.
Under ICAO, non-instrument and non-precision runways have a minimum of 6 threshold lights, with a displaced threshold plus wing-bar exception, CAT I uses spacing of no more than 3 m, and CAT II and III use uniform spacing of no more than 3 m. The FAA basic configuration is 3 per side (6 total) for a visual runway and 4 per side (8 total) for an instrument runway. These are minimum configuration quantities, and a category-specific FAA threshold formula is not yet incorporated.
Both are entered per the approved project layout, because a generic wing-bar formula is not applied and the arrangement is figure-specific. ICAO requires at least six runway-end lights, so confirm the quantity against the project drawing. The CAT I, II and III threshold count is based on the edge-light-row span (runway width plus twice the edge-light offset), a maximum spacing of 3 m by default, and an endpoint arrangement setting that is exposed rather than hard-coded.
PASS means the installed quantity meets the calculated minimum, and FAIL means it is below that minimum. REVIEW is given for precision-category geometry, a displaced threshold or a project-specific arrangement, which needs drawing review regardless of the number entered. N/A means no installed quantity was entered, so compliance is not checked.
No. It is a calculated nominal quantity, not a final BOQ quantity, and it reports installed fixtures without a serviceability adjustment. Serviceability percentages belong in a separate calculation. Verify final fixture locations, colour configuration and the threshold and runway-end arrangement against the approved aerodrome lighting layout, especially for displaced thresholds and precision runways.
Please read before relying on any content on this page or on any result or record produced by it.