Reading a VTC — transcript

00:00:00.300 --> 00:00:05.760 Reading a V T C: chart features, elevation and distance.

00:00:06.600 --> 00:00:11.121 Near major aerodromes, use the Visual Terminal Chart, or V T C.

00:00:11.121 --> 00:00:14.088 At one to two hundred and fifty thousand,

00:00:14.088 --> 00:00:17.267 one centimetre is two and a half kilometres.

00:00:17.267 --> 00:00:22.848 The World Aeronautical Chart is one to a million: less detail, much more area.

00:00:23.700 --> 00:00:30.100 A job near a major airport? Start with the current V T C, and read its legend.

00:00:31.000 --> 00:00:36.706 The chart shows what you can see from the air: towns, roads, railways,

00:00:36.706 --> 00:00:43.537 rivers and golf courses. Powerlines have tick marks. Magenta lines are V F R routes,

00:00:43.537 --> 00:00:45.707 busy with crewed aircraft.

00:00:46.600 --> 00:00:51.890 Terrain is in feet above mean sea level. Brown contours join equal elevations,

00:00:51.890 --> 00:00:56.310 and close lines mean steep ground. Colour tints band the heights,

00:00:56.310 --> 00:00:58.721 and spot heights mark the hilltops.

00:00:59.600 --> 00:01:05.224 Obstacles show two numbers. Fifteen twenty-three, with three oh five in brackets:

00:01:05.224 --> 00:01:08.174 the top is fifteen twenty-three feet AMSL,

00:01:08.174 --> 00:01:11.329 and the structure is three oh five feet tall.

00:01:12.200 --> 00:01:16.391 On a W A C, each grid square has a maximum elevation figure.

00:01:16.391 --> 00:01:20.376 Thirty-five means about three thousand five hundred feet.

00:01:21.200 --> 00:01:25.980 Quick check. The contour lines bunch up tightly. What does that tell you?

00:01:27.500 --> 00:01:28.467 Steep ground.

00:01:29.300 --> 00:01:33.167 To measure a track, draw a line between the two points.

00:01:33.167 --> 00:01:38.069 Centre the plotter where the line crosses a meridian, align its north,

00:01:38.069 --> 00:01:43.040 and read the angle. Brisbane to Archerfield is about two one zero true.

00:01:43.900 --> 00:01:50.516 The reciprocal is one eighty away: zero three zero true. These are true directions;

00:01:50.516 --> 00:01:54.297 the navigation video shows how to convert them.

00:01:55.100 --> 00:02:01.896 For distance, use the latitude scale. One minute of latitude is one nautical mile.

00:02:01.896 --> 00:02:07.299 Never use the longitude scale: meridians converge, so it changes.

00:02:08.100 --> 00:02:11.086 Within three nautical miles of a controlled aerodrome?

00:02:11.086 --> 00:02:15.049 Set the dividers to three minutes of latitude, and swing them around it.

00:02:15.900 --> 00:02:22.161 Chart heights are AMSL, but your limit is four hundred feet AGL. So add them.

00:02:22.161 --> 00:02:25.694 Kingaroy sits at fourteen ninety-four feet,

00:02:25.694 --> 00:02:30.189 so four hundred AGL is about eighteen ninety-four AMSL.

00:02:31.000 --> 00:02:35.670 If a step above starts at A zero two zero, that's two thousand feet AMSL.

00:02:35.670 --> 00:02:38.889 You're below it, but only by about a hundred feet.

00:02:39.700 --> 00:02:46.157 Recap: V T C for detail, W A C for the big picture. Heights are AMSL.

00:02:46.157 --> 00:02:53.075 Use the latitude scale for distance. And add your height to the elevation.

00:02:53.900 --> 00:02:58.576 Final check. Your track out is two one zero true. What's the reciprocal?

00:03:00.100 --> 00:03:04.097 Zero three zero true. Add or subtract one eighty.