🔍 Key Concepts

• Relationship between gyro course (pgc), true course (°T), magnetic course (°M), and standard compass course (psc) • How to apply variation and deviation with the correct algebraic signs • Memory aids for gyro error: "gyro best, error west" and "gyro least, error east"

💭 Think About

• Start from the per gyro compass (pgc) course they give you and think: what is the next logical reference you should convert it to before you can reach per standard compass (psc)? • Ask yourself whether you already know, from earlier in the exam, the gyro error, variation, and deviation for this area and time, and in what order they must be applied. • When you change from one reference (gyro) to another (standard compass), are you adding or subtracting east/west corrections? Write a small chain like: G → T → M → C and mark each step.

✅ Before You Answer

• Before picking an answer, make sure you have written a clear conversion chain: G → T → M → C with the sign (+/−) for each correction. • Verify you are using the correct sign convention: east errors/variation/deviation are treated one way, west the other—check your rule for each. • Confirm that your final psc value is reasonably close to the original pgc value (not a huge difference) and that it matches the expected direction of all your applied corrections.