BDCA CPL Knowledge Exam study materials
BDCA CPL Knowledge Exam study resources

BDCA CPL Knowledge Exam: Navigation

BDCA CPL Knowledge Exam · Work through your exam, one topic at a time.

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Navigation

Position, track and time

Navigation questions test your ability to determine position, plan and follow a route, and manage time and fuel. Understand the relationship between true, magnetic and compass headings; between track, heading and drift; and between indicated, true and ground speed. Know how to use the triangle of velocities and how to convert between units of distance, speed and time.

Traps

Common traps include mixing true and magnetic values, applying variation in the wrong direction, and forgetting to convert units before computing. Another trap is confusing track with heading when wind is present. Questions may also test the difference between a planned and an actual position, or between a fix and a dead-reckoning estimate.

Worked example

An aircraft tracks 090 degrees at 120 knots true, with wind from the north at 20 knots. The crosswind component pushes the aircraft south, so the heading must be offset into wind, and the headwind component reduces ground speed. Compute the wind triangle, then apply variation to obtain the magnetic heading.

Rule of thumb

Variation east, magnetic least: subtract easterly variation from true to get magnetic. Always state the reference (true or magnetic) before using an angle.