Airports — Runway and Pre-Threshold

This page covers the first two tabs of the CapAero form: the one that draws the surface marking of the runway, and the one that repeats a geometry across the pre-threshold area. The remaining tabs (taxiway, apron, reports and tools) are in Airports — Taxiway, Apron and Tools.

What it does

The command opens the CapAero form. On the Runway tab you define the runway centreline — by selecting an existing line or by clicking two points — and from it CapAero assembles the whole surface marking in one pass and draws it.

The list on the left (7) holds the runway elements. The tick box beside each row (2 to 6, 13 to 15) says whether that element is drawn; clicking the name swaps the parameter panel on the right without touching the box. The two gestures are independent: you can read the touchdown-zone parameters with the touchdown zone switched off.

The elements are:

Everything the runway draws goes to the horizontal-marking layers of the active country profile's catalogue — the white marking layer for the marks and the black one for the contrast painting. The three layers named above are fixed and do not pass through the catalogue.

Live preview

Once the centreline is acquired, any change redraws: ticking or unticking an element, switching a radio button, or typing in a field and pressing Enter. The redraw erases the previous batch before drawing the new one, so the runway is never duplicated. Leaving a field without pressing Enter does not redraw.

Three links sit below the draw button:

• Zoom — not available in this version; the status bar says so.
• Update — erases the last batch and redraws it, useful when something outside the form has touched the drawing.
• Reset — erases the last batch and does not redraw, leaving the drawing clean.

Length and LDA

Bottom right, the form shows two numbers after every draw: Length, the length of the acquired centreline, and LDA, that length minus twice the Gap start (24) — the landing distance available that the automatic aiming-point calculation uses.

Minimum length

CapAero refuses centrelines shorter than 200 m and widths of zero or less: nothing is drawn and the warning appears in the status bar.

Workflow

1. Run CAPCAD_AERO_RUNWAY (or CAPCAD_AERO and pick the Runway tab).
2. Fill in the width (21). To derive it from the landing gear instead, type the OMGWS (23) and pick the Code (22) — the width is filled from the table.
3. Tick the elements you want in boxes 2 to 6 and 13 to 15, or use the top box (1) to switch them all on at once.
4. Choose how the centreline is obtained — Select line (17) or By 2 points (18) — and click the button (16), whose caption follows the choice.
5. The form hides, you select the line or click the two points, and the runway appears.
6. Walk the element list (7) and tune each panel. Every Enter redraws.
7. When it looks right, close the form. The drawing stays; the field values are remembered for next time.

The form

The numbers below apply to the whole page. The right-hand panel changes with the element selected in the list (7); everything else on the tab stays put, which is why controls 1 to 28 appear in every capture.

The screenshots on this page were captured in a Portuguese session; the control numbering is the same in every language, and the tables quote the English captions the form shows in an English session.

Element Area selected: limits, border lines and pre-threshold retention.

Elements and centreline (common to every panel)

Draw, runway and contrast (common to every panel)

The Info link beside OMGWS opens the table it uses:

Area element

Threshold element

Threshold stripes are 30 m long, a fixed value. They start at Gap start (24) from each end; if they do not fit (gap start + 30 m longer than the runway), the threshold and the designation on that side are not drawn.

Designation element

The designation is the initial azimuth of the great circle between the two ends of the centreline, corrected by the variation, divided by ten and rounded; a resulting azimuth of zero becomes runway 36.

The airport-alphabet numerals, here the pair "28", generated by the engine.

Center-line element

Centre line with Draw as linetype: a single polyline, the cadence living in the layer's linetype.

Centre line with Draw rectangles: every mark becomes geometry of its own, measurable and hatchable.

Touchdown zone element

Touchdown zone with 3-2-1 pattern and fixed spacing 122.5: the groups lose a bar at every step.

The same runway with Divisions = 4 and start 150: the pairs spread over the length, without the 3-2-1 taper.

Aiming point element

The automatic table, by LDA:

Aiming point computed for a 2 500 m runway: start 400 m, bars of 45 × 6 m.

Runway: pre-threshold tab

The four buttons load a geometry into the Divider Assistant and apply an airport preset, so all you have to do is point at the path to repeat.

The angled mark of button 66, generated by the engine.

The arrow head of button 67 (the arrow body is not generated by this call).

The X mark of button 68.

How the options combine

The first 700 m of a 2 500 × 45 m runway with every element on, designation 28 R, cadence 30x20 and gap start 15 m. Left to right: threshold stripes, designation, the 3-2-1 groups of the touchdown zone, the aiming point (the long bars) and the cadenced centre line — here a single polyline, hence drawn continuous. The dashed rectangle is the limits layer.

Threshold detail: twelve 2 m stripes separated by 1.5 m, with the 3 m central gap, and the 0.9 m border lines pulled inside the area.

The designation drawn: letter starting 12 m and numerals 21 m after the end of the threshold stripe (here, with gap start zero, at 42 m and 51 m), height 9 m, read from the approach direction.

Threshold without contrast painting: the white stripes only (shown light).

The same threshold with Add with offset ticked: the threshold contrast fills the gaps between the white stripes and adds a wide black stripe on the centreline. Note that the offset (26) is not used here — the contrast width comes from the stripe pitch itself.

Remembered between sessions

On closing the form, CapAero saves the contents of the runway text fields — width, border width, gap start, the three threshold gaps, the three designation fields and the magnetic variation, the centre-line fields, the six touchdown-zone fields and the four aiming-point fields — and reloads them the next time it opens. Tick boxes, radio buttons and combos are not remembered: they return to the form defaults.

The acquired centreline is not remembered: reopening CapAero means pointing at the runway again.

Notes

• The draw button replaces the previous drawing only while the centreline is the same. Acquiring a new centreline makes the command forget the previous batch, which becomes part of the drawing like any other geometry.
• The Radius element is not available in this version; its panel says so instead of offering parameters.
• The parameter panel is chosen by the position of the item in the list, not by its text, so translating the interface does not misalign the panels.
• The three Presets (28) write exactly the same values. They do not distinguish runway category.
• The minimum-length warning (200 m) and the other warnings appear in the form's status bar, one at a time — the last one raised.
• The Zoom link is not available in this version.
• The centre-line contrast, when Centerline as continuous line (27) is ticked, is generated from a copy of the centre line and does not replace the white mark.
• The marks go to the white and black horizontal-marking layers of the active country profile's catalogue. CAPAERO_RUNWAY_LIMITS, CAPCAD_AERO_LIGHTS_YELLOW and CAPCAD_AERO_LIGHTS_RED are fixed names and do not pass through the catalogue.
• Pressing Enter in fields on other tabs (sign letter size, label colours, arrow size) also fires the runway redraw.