SIRS NAVIGATION LTD
COMPONENT MAINTENANCE MANUAL
G. Magnetic Correctors
(1) Align the magnetic correctors to their neutral-effect alignment (Ref. Fig. 11001).
(2) Align the compass to North.
(3) Turn the 'C' ‘corrector spindle’, with the ‘corrector key’ (220) through 90
°
, i.e. the
indicator lines must be at 90
°
to the index lines.
(4) Record the angle that the card has turned through and turn the ‘corrector
spindle to its neutral-effect alignment (Ref. Fig. 11001).
(5) Follow the procedures detailed in paragraphs (3) and (4) but turn the 'C'
corrector in the opposite direction. Record the results.
(6) The compass card must turn through more than 25
°
and less than 35
°
. The
difference between each test must not be more than 2
°
.
(7) Align the compass to South.
(8) Follow the procedures in paragraphs (3) to (6).
(9) Align the compass to East.
(10) Follow the procedures in paragraphs (3) to (6) but turn the ‘B’ corrector.
(11) Align the compass to West.
(12) Follow the procedures in paragraphs (3) to (6) but turn the ‘B’ corrector.
H. Angle of Tilt
(1) Assemble the ‘Tilt stand’, with compass attached, to the ‘divided test head’.
(2) Turn the compass forward to an angle of 20
°
from the vertical.
(3) Turn the compass through 360
°
at an approximate rate of 6
°
per second.
Examine the compass card to make sure it is free to turn.
(4) Follow the procedure in paragraph (3) but at 20
°
to the left, right and rear.
PAGE 1009
APR 10/03
34-25-21
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