🔍 Key Concepts

• Using charted bearings to fixed objects (like Trestle "A" of the Chesapeake Bay Bridge-Tunnel) to find gyro error • Relationship between True (T) and Gyro (G):
T = G + gyro error (E) • Memory aid for direction of error: "Gyro best, error west – Gyro least, error east"

💭 Think About

• From your position as you pass through the bridge-tunnel, what is the charted true bearing of Trestle "A"? (Look this up on the chart or exam diagram.) • Compare the observed gyro bearing (198°pgc) with the charted true bearing. Is the gyro reading greater than or less than true? • Based on whether gyro is best (larger) or least (smaller) than true, should the gyro error be east or west, and by how many degrees?

✅ Before You Answer

• Confirm you are using the correct charted TRUE bearing for Trestle "A" from the specified position (not reciprocal, not magnetic). • Use the formula T = G + E and solve carefully for E = T − G; check the sign (east vs west). • Double-check that you apply the memory aid correctly: if Gyro > True then error is W, if Gyro < True then error is E.