ATC Flight Plan — Page 215, Lesson 216

I want to walk you through how to fill in the route portion of an ATC flight plan — specifically Item 15, which is the route field. This is where you describe the entire path your flight will take, from departure to destination, using a precise set of codes and rules. Let's start with how you define a position that doesn't have a standard five-letter coded designator — that is, a point that isn't a named waypoint or reporting point. If there are no coded designators available, you have two options. The first option is latitude and longitude. You can express this in degrees only, using seven characters — for example, 56N105W, which is 56 degrees north, 105 degrees west. Or you can use degrees and minutes, which takes eleven characters — for example, 4715N16005E, meaning 47 degrees 15 minutes north, 160 degrees 5 minutes east. Another example is 6010N06206W. Notice the format: no spaces, no symbols like degree signs or commas — just the digits and the N, S, E, or W letters. The second option for defining a point without a coded designator is bearing and distance from a navigation aid. For instance, SAM090035 indicates a point 35 nautical miles on a bearing of 090 degrees magnetic from the Southampton VOR. So the format is the three-letter navaid identifier, then the three-digit bearing in degrees magnetic, then the three-digit distance in nautical miles. Now let's talk about the use of DCT, which stands for "direct." DCT tells air traffic control that you are flying directly from one point to another, not along a published ATS route — that's Air Traffic Service route, like an airway. Here are the rules for when to use DCT. First, if your departure airfield is located on or connected to an ATS route, then the coded designator of that route — the airway identifier — will be the first entry in your route field. But if the departure airfield is not on or connected to an ATS route, then the first entry will be DCT, followed by the joining point where you join the route, followed by the designator of that ATS route. So it looks like: DCT [joining point] [route designator]. Second, if the destination airfield is not on or connected to an ATS route, the last entry in the route field will be DCT. That tells ATC you are going direct from the last point on the airway to the destination. Third, use DCT between coded designators that are not connected by ATS routes. So if you have two waypoints that are not linked by an airway, you put DCT between them. Fourth, use DCT between a designated reporting point — that's a named point on the chart — and a position that is defined by latitude and longitude or by a bearing and distance from a navaid, when that position is outside the ATS route. Fifth, use DCT between a latitude and longitude, or a navaid bearing and distance, and a designated reporting point that is on an ATS route. Sixth — and this is important — DCT is not required between successive points that are both defined by latitude and longitude or by a bearing and distance from a navaid. If you have two such points in a row, you just list them one after the other without DCT. Finally, a key rule about what goes into Item 15: only points of change are to be entered. You insert each point at which there is a change of route, a change of speed or level, or a change of flight rules. For speed or level, a change of speed is defined as 5% of true airspeed or 0.01 Mach or more. And here's a critical detail — if there is a change of level or speed, both must be entered even though only one has changed. So if you change altitude but keep the same speed, you still enter both the new speed and the new level at that point. And if you change speed but stay at the same level, you still enter both. After the point of change, you follow it with the designator of the ATS route — even if it is the same route as before the change — or you follow it with DCT if the next point is outside the ATS route. There are figures in the book that show examples of these rules — Figure 12.1 is a specimen ATC flight plan, and Figures 12.2 through 12.5 illustrate the DCT rules and the point-of-change entries.