is no magnetic interference. Lines, oriented to magnetic north,  are painted every 30°, as shown in  Figure 5-18 . Step 2: Determine the Compass Course Magnetic Course (190°, from step 1) ± Deviation (–2°, from  correction card) = Compass Course (188°) NOTE: Intermediate magnetic courses between those listed  on the compass card need to be interpreted. Therefore, to  steer a true course of 180°, the pilot would follow a compass  course of 188°.  To find true course when the compass course is known, remove  the variation and deviation corrections previously applied: Compass Course ± Deviation = Magnetic Course ± Variation  = True Course The pilot or AMT aligns the aircraft on each magnetic  heading and adjusts the compensating magnets to minimize  the difference between the compass indication and the actual  magnetic heading of the aircraft. Any error that cannot be  removed is recorded on a compass correction card, like the  one in  Figure 5-19 , and placed in a cardholder near the  compass. If the pilot wants to fly a magnetic heading of  120° and the aircraft is operating with the radios on, the pilot  should fly a compass heading of 123°. When turning in a southerly direction, the forces are such that  the compass float assembly lags rather than leads. The result  is a false southerly turn indication. The compass card, or float  assembly, should be allowed to pass the desired heading prior  to stopping the turn. As with the northerly error, this error is  amplified with the proximity to either pole. To correct this  lagging error, the aircraft should be allowed to pass the desired  heading prior to stopping the turn. The same rule of 15° plus  half of the latitude applies here (i.e., if the airplane is being  operated in a position around the 30° of latitude, the turn  should be stopped 15° + 15° + 30° after passing the desired  heading).  [Figure 5-20B] The magnetic dip and the forces of inertia cause magnetic  compass errors when accelerating and decelerating on Easterly  and westerly headings. Because of the pendulous-type  mounting, the aft end of the compass card is tilted upward  when accelerating, and downward when decelerating during  The corrections for variation and deviation must be applied  in the correct sequence as shown below starting from the  true course desired. Step 1: Determine the Magnetic Course True Course (180°) ± Variation (+10°) = Magnetic Course (190°) The Magnetic Course (190°) is steered if there is no deviation  error to be applied. The compass card must now be considered  for the compass course of 190°.  Acceleration Error Southerly Turning Errors Northerly Turning Errors Figure 5-18. Utilization of a compass rose aids compensation for  deviation errors. The center of gravity of the float assembly is located lower  than the pivotal point. As the airplane turns, the force that  results from the magnetic dip causes the float assembly to  swing in the same direction that the float turns. The result  is a false northerly turn indication. Because of this lead of  the compass card, or float assembly, a northerly turn should  be stopped prior to arrival at the desired heading. This  compass error is amplified with the proximity to either pole.  One rule of thumb to correct for this leading error is to stop  the turn 15° plus half of the latitude (i.e., if the airplane is  being operated in a position around the 40° of latitude, the  turn should be stopped 15° + 20° = 35° prior to the desired  heading).  [Figure 5-20A] Figure 3-19. A compass correction card shows the deviation correction for any heading. Figure 5-19. A compass correction card shows the deviation  030  060  E  120  150  S  210  240  W  300  330  N  True north 5-13