(a)
Calculate deviation west. (Dw)

Dw = MHw - CHw

(b)
Calculate deviation east. (De)

De = MHe - CHe

(c)
Calculate single cycle=or.(B)

B = De - dw
 2

(12)
Repeat step (11) for No. 2 system.

(13)
Correct for index error (coefficient A) in system No. 1 as follows:

(a)
Calculate index error. (A).

A = Dn + Ds + Dw + De
 4

(b)
Calculated index error shall not exceed 1 degree.

(c)
Index error cannot be removed from standby magnetic compass.

(14)
Repeat step (13) for No. 2 system.

(15)
Tow airplane to northerly heading once more and commence 12 point residual error swing.

(16)
Record magnetic heading at each 30-degree compass heading and actual reading of master compass card for each system.

(17)
Check that residual deviation does not exceed 2 degrees on each 30-degree heading.

NOTE:  Check transit calibration against heading markers before taking heading reading at each point.
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E.  Restore Airplane to Normal
(1)  
Remove all items of test equipment.

(2)  
If there is no further need for external power, remove external power.

3.  Swing Standby Compass System
NOTE:  The standby compass may be calibrated using one of two different procedures. One of the procedures is contained in the following paragraphs. This procedure tows the aircraft to swing the compass. The other procedure is contained in Section 34-24-11, Magnetic Standby Compass - Maintenance Practices (Compass Swing). It uses a compass calibrator to swing the compass.
A.  General
(1) Compensation for single cycle errors only, is provided on the standby compass.
B.  Equipment and Materials
(1)  All items listed in paragraph 2.B.
C.  Prepare for compass swing.
(1)  
Repeat paragraphs 2.C(1), (2), (3), and (5) thru (7).

CAUTION:  BE SURE THAT THE GROUND DOWN LOCKS ARE IN PLACE BEFORE PROCEEDING WITH STEP (2), OR THE LANDING GEAR WILL BE IN DANGER OF COLLAPSE.

(2)  
Energize the landing gear lever latch solenoid after observing above caution by grounding terminal A of latch solenoid. Allow at least 20 minutes before commencing swing.

CAUTION:  DO NOT MOVE LANDING GEAR LEVER AFTER COMPLETING STEP (2).
NOTE:  It is necessary to energize the landing gear latch solenoid since it is energized during flight, and its magnetic field can affect the accuracy of the standby compass system. When the solenoid is energized it frees the landing gear lever from its latching mechanism. It is then possible for the lever to be moved to UP.
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D.  Swing Compass
(1)  
Adjust the compensators on the compass to align the dots.

(2)  
Allow the system to settle and note compass heading.

(3)  
Calculate airplane heading as in par. 2.D.(4).

(4)  
Record true magnetic heading and standby compass heading.

(5)  
Tow the airplane to within 2 degrees of a westerly heading, and repeat steps (2) thru (4) above.

(6)  
Tow the airplane to within 2 degrees of a southerly heading, and repeat steps (2) thru (4) above.

(7)  
Calculate the N-S single cycle error as in par. 2.D.(8), and adjust compass N-S control accordingly.

(8)  
Tow the airplane to within 2 degrees of an easterly heading, and repeat steps (2) thru (4) above.

(9)  
Calculate the E-W single cycle error as in par. 2.D.(11), and adjust compass E-W control accordingly.

(10)
Tow airplane to northerly heading once more and commence 8 point residual error swing.

(11)
Record magnetic heading at each 45 degrees compass point (TO FLY heading), and the actual reading of the standby compass (TO STEER heading).

(12)
Check that the difference between TO FLY-headings and TO STEER headings does not exceed + 8 degrees (FAA requirement) or ± 4 degrees (CAA requirement) for any of the 8 points calibrated. Check also that the difference between the maximum positive and the maximum negative error does not exceed 10 degrees (FAA requirement) or 7 degrees (CAA requirement).

(13)
Complete a compass correction card for the system.

(14)
See CAUTION below and restore airplane to normal as in par. 2.E.

CAUTION:  BEFORE COMPLETING STEP (14) ENSURE LANDING GEAR LEVER IS IN DOWN POSITION AND GROUNDING JUMPER IS REMOVED FROM TERMINAL A OF LANDING GEAR LEVER LATCH SOLENOID.
　
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