Magnetic Compass Magnetic Compass l l Oldest and

Magnetic Compass

Magnetic Compass l l Oldest and most reliable instrument Construction of Compass l l l l l Two bar magnets Jeweled bearing Compass card Expansion chamber Compass fluid Compensating magnet Compass weight Lubber line www. allstar. fiu. edu/aero/Mag. Comp. htm

Different errors Oscillation l Variation l Deviation l Compass dip l Northerly turning l Acceleration l

Oscillation Result of movement l Weights in compass l l Correction l Take average heading

Variation l Difference of true and magnetic north l Correction l Use chart correction

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

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

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

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

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