First, let me explain the structure — Page 154, Lesson 139

I want to walk you through a set of practice exercises that bring together everything we've been learning about the navigation computer — both the slide rule face and the wind face — to complete a full flight plan. First, let me explain the structure. You'll see a table with columns for each leg of a flight. Across the top, the columns are: ALT in feet, TEMP in degrees Celsius, CAS in knots, TAS in knots, TRACK in degrees true, W/V (that's wind velocity — direction and speed), HDG in degrees true, VAR (magnetic variation), HDG in degrees magnetic, DEV (compass deviation), HDG in degrees compass, GS in knots, DIST in nautical miles, and TIME in minutes. Now, the key instruction here is important: you must work across the rows, row by row. Do not go column by column. The reason is that working row by row makes you think about each individual operation and what you're trying to achieve. If you go column by column, it just becomes a mechanical exercise with no thought behind it. Let's look at Flight Plan 1, row by row, so you can see how this works in practice. Row 1: Altitude 2000 feet, temperature -10°C, CAS 160 knots. From that, you compute TAS as 159 knots. Your required track is 100° true, and the wind velocity is 330/17 — that's wind from 330° true at 17 knots. Using the wind side of the navigation computer, you find that your heading to maintain that track is 095° true. Then you apply variation: 5° West. Remember, variation west is subtracted from true to get magnetic, so 095° true minus 5°W gives 100° magnetic. Then you apply deviation: 1° West. Deviation west is also subtracted, so 100° magnetic minus 1°W gives 101° compass. Your ground speed works out to 169 knots. The distance for this leg is 50 nautical miles, so the time is 18 minutes. Row 2: Altitude 4700 feet, temperature -2°C, CAS 170 knots gives TAS 180 knots. Track required is 227° true, wind 300/10. Heading comes out to 230° true. Variation here is 3° East — and remember, east variation is added to true to get magnetic, so 230° true plus 3°E gives 227° magnetic. Wait, let me check that — 230 plus 3 is 233, but the table shows 227° magnetic. Let me re-read: the table says HDG°(T) 230, VAR 3°E, HDG°(M) 227. That means the variation is applied as 3° East subtracted? No — in standard practice, variation east is added to true to get magnetic, but the table shows 230° true minus 3° gives 227° magnetic. That would mean the variation is actually 3° West, or the convention here is different. Let me look more carefully at the table: it says VAR 3°E, and HDG°(M) is 227. So 230 minus 3 equals 227 — that means east variation is being subtracted here. That's actually the correct convention for converting true to magnetic: variation east is subtracted, variation west is added. I had that backwards earlier. So 230° true minus 3°E gives 227° magnetic. Then deviation is 2° East, so 227° magnetic plus 2°E gives 225° compass. Ground speed is 177 knots, distance 112 nautical miles, time 38 minutes. Row 3: Altitude 4000 feet, temperature -10°C, CAS 175 knots gives TAS 180 knots. Track 134° true, wind 262/17. Heading 138° true. Variation 3° West — so 138° true plus 3°W gives 141° magnetic. Deviation 1° East, so 141° magnetic plus 1°E gives 140° compass. Ground speed 190 knots, distance 30 nautical miles, time 9.5 minutes. Row 4: Altitude 2000 feet, temperature +2°C, CAS 170 knots gives TAS 172 knots. Track 157° true, wind 110/12. Heading 154° true. Variation 6° West — 154° true plus 6°W gives 160° magnetic. Deviation 2° West — 160° magnetic plus 2°W gives 162° compass. Ground speed 165 knots, distance 38.5 nautical miles, time 14 minutes. Row 5: Altitude 6000 feet, temperature -3°C, CAS 154 knots gives TAS 167 knots. Track 100° true, wind 320/18. Heading 096° true. Variation 4° East — 096° true minus 4°E gives 092° magnetic. Deviation 1° West — 092° magnetic plus 1°W gives 093° compass. Ground speed 180 knots, distance 60 nautical miles, time 20 minutes. Row 6: Altitude 5000 feet, temperature -15°C, CAS 150 knots gives TAS 155 knots. Track 050° true, wind 110/45. Heading 064° true. Variation 8° West — 064° true plus 8°W gives 072° magnetic. Deviation 2° East — 072° magnetic plus 2°E gives 070° compass. Ground speed 127 knots, distance 13 nautical miles, time 6 minutes. Row 7: Altitude 10000 feet, temperature -8°C, CAS 173 knots gives TAS 200 knots. Track 320° true, wind 181/27. Heading 315° true. Variation 3° East — 315° true minus 3°E gives 312° magnetic. Deviation is shown as -3 — that means 3° West deviation, so 312° magnetic plus 3°W gives 315° compass. Ground speed 219 knots, distance 44 nautical miles, time 12 minutes. Now let's look at Flight Plan 2, which follows the same structure. Row 1: Altitude 5000 feet, temperature +5°C, CAS 170 knots gives TAS 183 knots. Track 070° true, wind 230/25. Heading 073° true. Variation 5° West — 073° true plus 5°W gives 078° magnetic. Deviation 1° East — 078° magnetic plus 1°E gives 077° compass. Ground speed 206 knots, distance 86 nautical miles, time 25 minutes. Row 2: Altitude 6500 feet, temperature -2°C, CAS 170 knots gives TAS 186 knots. Track 234° true, wind 210/30. Heading 230° true. Variation 3° West — 230° true plus 3°W gives 233° magnetic. Deviation 2° East — 233° magnetic plus 2°E gives 231° compass. Ground speed 158 knots, distance 71 nautical miles, time 27 minutes. Row 3: Altitude 6000 feet, temperature +2°C, CAS 174 knots gives TAS 190 knots. Track 240° true, wind 210/22. Heading 237° true. Variation 4° West — 237° true plus 4°W gives 241° magnetic. Deviation 1° East — 241° magnetic plus 1°E gives 240° compass. Ground speed 171 knots, distance 57 nautical miles, time 20 minutes. Row 4: Altitude 7500 feet, temperature +2°C, CAS 175 knots gives TAS 197 knots. Track 166° true, wind 110/30. Heading 159° true. Variation 6° West — 159° true plus 6°W gives 165° magnetic. Deviation 3° East — 165° magnetic plus 3°E gives 162° compass. Ground speed 179 knots, distance 89 nautical miles, time 30 minutes. Row 5: Altitude 8000 feet, temperature -2°C, CAS 174 knots gives TAS 196 knots. Track 190° true, wind 245/36. Heading 196° true. Variation 4° East — 196° true minus 4°E gives 192° magnetic. Deviation 1° West — 192° magnetic plus 1°W gives 193° compass. Ground speed 180 knots, distance 60 nautical miles, time 20 minutes. Row 6: Altitude 9000 feet, temperature -5°C, CAS 180 knots gives TAS 206 knots. Track 050° true, wind 110/45. Heading 061° true. Variation 11° West — 061° true plus 11°W gives 072° magnetic. Deviation 2° East — 072° magnetic plus 2°E gives 070° compass. Ground speed 180 knots, distance 13 nautical miles, time 4 minutes. Row 7: Altitude 12000 feet, temperature -11°C, CAS 184 knots gives TAS 220 knots. Track 324° true, wind 190/47. Heading 315° true. Variation 3° East — 315° true minus 3°E gives 312° magnetic. Deviation is +2 — that's 2° East deviation, so 312° magnetic plus 2°E gives 310° compass. Ground speed 250 knots, distance 50 nautical miles, time 12 minutes. So the whole point of these exercises is to practice the complete sequence: starting with altitude and temperature to find true airspeed from calibrated airspeed, then using the wind side of the computer with your required track and the wind velocity to find the heading you need to steer and the ground speed you'll achieve, then applying magnetic variation to get magnetic heading, then applying compass deviation to get compass heading, and finally computing the time for the leg from the distance and ground speed. Each row is a complete navigation problem that ties all those steps together.