21 S 15 12 21 S 15 12 21 S 15 12 D $_{i}$p $_{ }$e f $_{f}$e c t C A R D C A R D Left turn No error Right turn D i p e f e c t DIP DIP DIP B 3 N 33 30 3 N 33 30 3 N 33 30 C A R D D $_{i}$p $_{ }$e f $_{f}$e c t C A R D D i p e f c t Left turn No error Right turn A DIP DIP DIP Figure 5-20. Northerly turning error. changes of airspeed. When accelerating on either an easterly  or westerly heading , the error appears as a turn indication  toward north. When decelerating on either of these headings,  the compass indicates a turn toward south. The word "ANDS"  (Acceleration-North/Deceleration-South) may help you to  remember the acceleration error.  [Figure 5-21] Oscillation is a combination of all of the other errors, and it  results in the compass card swinging back and forth around  the heading being flown. When setting the gyroscopic  heading indicator to agree with the magnetic compass, use  the average indication between the swings. Oscillation Error  Figure 5-21.  The effects of acceleration error. NORTH S o u t h OBS  N  E  W  3  33  24  21  15  1 2  30 6 NAV GS  View is from the pilot’s perspective, and the  movable card is reset  after each turn 5-14