TM 1-1500-204-23-4 Figure 4-21.  Compass Rose influence   on   compass   so   that   flight   conditions   are simulated as nearly as possible. (c) Compass rose method of compensating.  A compass rose is often used to obtain the  magnetic  headings  when    an  aircraft  compass    is being   compensated.      This   method   of   swinging   the compass is desirable, provided that care is exercised in aligning the aircraft  with  various  headings.    All  equipment  used  in the  vicinity  of  the  compass  rose  must  be  nonmagnetic materials.  Use the following procedures to compensate compass. 1 Place  aircraft  on  compass  rose,  as shown  in  figure  4-21,  and  head  toward  magnetic  north. Record compass reading in column 2, line 1 of DD Form 1613   (Pilot   Compass   Correction   Card)   as   shown   in figure  4-22.    Assume  that  the  compass  reading  is  8 degrees. 2 Turn  aircraft  to  the  east  magnetic heading  and  record  compass  reading  in  column  2,  line 3,  of  DD  Form  1613.    Assume  that  the  reading  is  86 degrees. 3 Turn  aircraft  to  the  south  magnet heading  and  record  compass  reading  in  column  2,  line 5,   of   DD   Form   1613.      Assume   that   reading   is   176 degrees. 4 Turn  aircraft  to  the  west  magnetic heading  and  record  compass  reading  in  column  2,  line 7, of DD Form 1613.  Assume that compass reading is 278 degrees. 5 Fill  in  the  column  headed  DEV;  if aircraft COM P is greater than the actual heading, DEV number will be positive; if aircraft COMP is smaller than the  actual  heading,  DEV  number  will  be  negative.    All additions and subtractions are algebraic. Compensating Residual Computation Table Swing Swing Comp Actual Aircraft Actual Aircraft Actual Rose Head (M) Comp.  (C)    Dev. Head (M) Comp.  (C) C to M Head (M) M to C N 000 000 008 +8 000 002 -2 000 +2 NE 045 045 046 -1 045 +1 E 090 090 086 -4 090 092 -2 090 +2 SE 135 135 135 0 135 0 S 180 180 176 -4 180 182 -2 180 +2 SW 225 225 224 +1 225 -1 W 270 270 278 +8 270 272 -2 270 +2 NW 315 315 315 0 315 0 COL NO. (1) (2) (2)-(1) (3) (4) (3)-(4) (3) (4)-(3) Figure 4-22.  DD Form 1613 (Compass Correction Card) 4-27