Aerodromes - Physical Characteristics — Page 390, Lesson 530

Let’s pick up right where we left off—we’ve covered the runway holding points and their distances from the runway centre line. Now I want to walk you through the next piece: the road holding position, and then we’ll move into aprons. First, the road holding position. This is a designated position at which vehicles may be required to stop and wait where the taxiway is also used as a road for aerodrome vehicular traffic. So imagine a taxiway that doubles as a road for airport vehicles—like fuel trucks or baggage carts. At that point, there’s a specific spot where those vehicles must halt and wait, just like an aircraft would at a holding point. Normally, a road holding point will have traffic lights to control the flow. And here’s the key rule: a road holding position must be established at an intersection of a road with a runway. The distances in the table we just looked at—the ones on page 384 for runway holding points—apply to road holding points as well. So the same 30, 40, 75, or 90 metres from the runway centre line, depending on the runway type and code number, govern where vehicles stop too. Now let’s move to aprons. This is a big one. The requirement is that aprons are provided where necessary to permit the embarking and disembarking of passengers, and the loading and off-loading of cargo and mail, as well as the servicing of aircraft—all without interference with aerodrome traffic. So an apron is that paved area where aircraft park, where passengers get on and off, where cargo is loaded, and where maintenance or servicing happens. The total apron area should be adequate to permit the expeditious handling of the aerodrome traffic at its maximum anticipated density. In plain terms, the apron has to be big enough to handle the busiest moment the airport will see, without slowing things down. Now, construction matters. Aprons are to be built to accommodate slow moving traffic, and in any case to withstand higher stresses than runways. That’s a critical point—aprons take more punishment than runways because aircraft are stationary, turning, and manoeuvring at low speed, which puts more load on the pavement. So they’re built stronger. Then we have the aircraft parking areas on aprons, which are called stands. These are to be marked, and they’re required to provide a minimum distance between parked aircraft. For code A, that distance is 3 metres. For code D and above, it’s 7.5 metres. So the code number of the aerodrome—A being smaller, D and above being larger—dictates how much separation you need between parked aircraft. Finally, there’s the isolated aircraft parking position. This is a designated area, or the control tower is advised of an area or areas, suitable for parking an aircraft that is known or believed to be the subject of unlawful interference, or which for other reasons needs isolation from normal aerodrome traffic. Think of it as a quarantine spot—if there’s a hijacking threat or some other reason to keep an aircraft away from everyone else, it goes here. This special area is not to be less than 100 metres from any other parking area, building, or public area, or over underground utilities—and those utilities include gas, aviation fuel, electrical, or communications cables. So it’s a minimum 100-metre buffer from everything else, and it can’t sit on top of buried fuel lines or cables. Let me tie that together. We have the road holding position for vehicles at runway intersections, with the same distance rules as aircraft holding points. Then we have aprons, built to handle the highest stresses, with marked stands and minimum separation distances. And finally, the isolated parking position—a safety-critical zone with a strict 100-metre clearance. That’s the full picture for this section.