Navigation, Flight Planning, and Cross-Country Operations
Cross-country soaring questions combine chart reading, wind, and the arithmetic of the final glide. The exam is less about paper flight logs than about deciding whether you can still reach the field.
Planning the task
- Set a task that fits the forecast cloud base, lift strength, and wind; declare a turnaround and an alternate landout with known, inspected fields.
- Convert winds aloft into a wind correction for each leg; the wind at 5,000 ft is usually stronger and more backed or veered than the surface wind.
- Carry a current chart, know the airspace along each leg, and note obstacles and minimum enroute altitudes.
The final glide
- Height required = distance divided by the glide ratio, plus a safety margin and an allowance for wind and sink.
- A headwind reduces the effective glide ratio; a tailwind improves it. In strong sink, add speed so you lose less height per mile.
- Round conservatively and keep at least 500-1,000 ft of margin over the last fence; arrive with height, not hope.
Worked example
You are 12 nm from the gliderport at 40:1 with a 10-kt headwind. In still air: 12 / 40 = 0.30 nm, or about 1,824 ft (1 nm = 6,076 ft). With the headwind, at 60 kt groundspeed the effective ratio falls to roughly 34:1, so 12 / 34 = 0.35 nm, about 2,140 ft, and a 1,000-ft margin gives about 3,100 ft AGL -- roughly 4,100 ft MSL if the field is at 1,000 ft. If your altimeter reads less, divert to the nearest landout now rather than waiting for stronger lift.
Traps that cost marks
Using the still-air glide ratio into a headwind; trusting GPS altitude instead of an altimeter with a current setting; failing to identify landout fields before you need them; and forgetting the airspace along the route.