1. Magnetic Compass

2. Magnetic Compass Oldest and most reliable instrument
Construction of Compass
Two bar magnets
Jeweled bearing
Compass card
Expansion chamber
Compass fluid
Compensating magnet
Compass weight
Lubber line

3. Different errors Oscillation Variation Deviation Compass dip
Northerly turning
Acceleration

4. Oscillation Result of movement Weights in compass Correction
Take average heading

5. Variation Difference of true and magnetic north Correction
Use chart correction

6. Deviation Errors in indicated heading due to local magnetic fields
Different in each airplane
Correction
Weights in compass
Correction in airplane

7. Compass Dip The angle of magnetic flow Correction
Weight installed in compass

8. Northerly Turning Errors
Compass unbalanced to compensate for vertical field
Unbalanced condition causes compass to overshoot north and undershoot south
Correction
UN/OS
Undershoot North
Overshoot South

9. Acceleration Error When heading east or west Correction
Compass indicates north on acceleration
Compass indicates south on deceleration
Correction
ANDS
Use compass only on straight and level flight

10. Conclusion Reliable Errors Be aware of correction Oscillation
Variation
Deviation
Compass Dip
Northerly turning errors
Acceleration errors
Be aware of correction
UNOS & ANDS
ECT