Aerodromes - Visual Aids, Markings and Signs — Page 417, Lesson 566

Let's pick up with the visual aids that mark the edges and distances of an aerodrome. I want to walk you through three specific markers, and then we'll touch on the docking guidance systems. First, boundary markers. These are provided at an aerodrome where the landing area has no runway. So if there's no defined runway strip, you mark the boundary of the landing area itself. The spacing depends on the type of marker. If you use the type shown in the figure, they're spaced at intervals of not more than 200 metres. If you use the conical type, they're spaced approximately 90 metres apart, with a marker at any corner. Now, the conical type — that's a cone not less than 50 centimetres high and not less than 75 centimetres in diameter at the base. The markers should be coloured to contrast with the background against which they'll be seen. You can use a single colour — orange or red — or two contrasting colours — orange and white, or alternatively red and white. The one exception is where those colours would merge with the background; then you'd need to choose something else. Let me show you what these look like. Next, fixed distance markers. These indicate the length of runway remaining. They consist of white numbers on a black background, positioned on the side of the runway at intervals of 1000 feet, counting down as you approach the end of the runway. The first marker is positioned 1000 feet — that's 300 metres — from the threshold of the landing runway. These are commonly called 'distance to go' markers, and they're mainly used at military aerodromes. Then we have parking stand markers. These are positioned as markings at the entrance to a parking stand, or as a sign positioned on a building at the end of the stand. The marker consists of white inscriptions on a blue background. Let me show you both the fixed distance and parking stand markers together. Now, let's talk about Visual Docking Guidance Systems. These are sometimes referred to as Nose-in Docking Guidance systems or Stand Entry Guidance systems. They provide guidance where pilot-interpreted alignment and stopping information is required for accurate parking, particularly at air-bridges. ICAO states that aircraft stand manoeuvring guidance lights should be provided to facilitate the positioning of an aircraft on an aircraft stand on a paved apron, or on a de/anti-icing facility intended for use in poor visibility conditions — unless adequate guidance is provided by other means. There are no learning objectives concerning Visual Docking Systems in this syllabus, but I'd advise you to read Chapter 4 of CAP 637, just in case a question comes up in the examination. So to recap: boundary markers define the edge of a landing area without a runway, fixed distance markers count down the runway remaining in 1000-foot increments, parking stand markers guide you into a stand, and Visual Docking Guidance Systems help with precise alignment and stopping at air-bridges.