Pilotage, dead reckoning and the wind triangle

Pilotage is navigating by looking out the window at landmarks on your chart. Dead reckoning is navigating by computing headings, groundspeed and time from known information. VFR cross-countries use both together.

From true course to compass heading

You measure a true course on the chart with a plotter. Then:

1. True course ± wind correction angle = true heading. Use an E6B or app to find the wind correction angle from the winds aloft. Correct into the wind.
2. True heading ± variation = magnetic heading. "East is least, west is best": subtract easterly variation, add westerly variation.
3. Magnetic heading ± deviation = compass heading, from the compass correction card.

A memory aid for the order: "True Virgins Make Dull Companions" (True, Variation, Magnetic, Deviation, Compass), applied to headings after the wind correction.

Groundspeed, time and fuel

The E6B also gives your groundspeed (headwinds slow you down, tailwinds speed you up). Then:

• Time = distance ÷ groundspeed. 60 NM at 100 knots = 0.6 hour = 36 minutes.
• Fuel = time × fuel burn. 0.6 hour at 8 gallons per hour = 4.8 gallons.

VFR cruising altitudes (91.159)

When cruising more than 3,000 feet AGL in level flight, choose an altitude based on your magnetic course:

• 0° to 179°: odd thousands plus 500 feet (3,500, 5,500, 7,500...).
• 180° to 359°: even thousands plus 500 feet (4,500, 6,500, 8,500...).

A memory aid: "East is odd, West is even odder," or "odd people fly east."