Navigation, Charts, and Flight Planning
Navigation questions ask you to plan a cross-country in a slow rotorcraft: read a sectional chart, convert between true, magnetic, and compass headings, apply wind, and compute time and fuel. Charts and flight planning are tested together.
Chart work
- Sectional charts are 1:500,000; one inch equals about 6.86 nm.
- Identify Class B, C, D, and E boundaries, special use airspace, obstacles, and airport data such as elevation, runway length, and CTAF.
- True course is measured from the chart with a plotter; variation converts true to magnetic using east is least, west is best (magnetic = true − east variation).
- Deviation comes from the compass card and is applied last to obtain compass heading.
Wind triangle
- Wind correction angle: sin WCA = crosswind component ÷ TAS.
- Groundspeed = TAS × cos WCA, then adjusted for the headwind or tailwind component.
- Fuel = burn rate × time, plus the rotorcraft reserve of 20 minutes day or 30 minutes night.
Worked example
True course 090°, TAS 90 kt, wind 360° at 20 kt, distance 120 nm. The wind is 90° off course, so crosswind = 20 kt and WCA = arcsin(20/90) ≈ 12.8°. Because the wind comes from the right, crab left: true heading 077°. Groundspeed ≈ 90 × cos 12.8° ≈ 87.8 kt. Time = 120 ÷ 87.8 ≈ 1.37 hr, about 82 minutes. At 8 gph that is roughly 11 gallons, plus reserve.
Planning for a gyroplane
Slow cruise speeds make wind a large fraction of groundspeed, so plan legs with alternates and check fuel at each checkpoint. Use pilotage and dead reckoning as primary, with GPS as a cross-check, and carry a current chart and plotter. Magnetic variation changes across the country and is printed on the chart's isogonic lines.
Traps
Applying variation in the wrong direction; using TAS as groundspeed; forgetting the rotorcraft fuel reserve; and planning a leg with no divert option when the wind shifts.