SIRS NAVIGATION LTD
COMPONENT MAINTENANCE MANUAL
(4) Put the compass into the support stand and put the support stand on the
‘divided test head’. Align the complete ‘test jig’ with magnetic north.
(5) Test the compass to find the directional error at each 10° heading. Record the
error from the divided test head scale.
(6) Directional errors must not exceed 2
°
.
E. Time of Swing
(1) Align the compass to North.
(2) Turn the compass card t30
°
with the deflector-magnet’ (item 11 of Page
Block 9001) and hold for 10 seconds to let the liquid become stable.
(3) Remove the deflector-magnet to let the compass card move to North. The time
for the card to turn through 25
°
(to the 5
°
mark) must be between 1.4 to 1.8
seconds.
(4) Follow the procedures in paragraphs (1) to (3) but move the card through -30°.
(5) Follow the procedures in paragraphs (1) to (4) and test at East, South and West.
F. Friction
Error
(1) Align the compass to North.
(2) Move the compass card t5
°
with the ‘deflector magnet’ and hold for 10
seconds to let the liquid become stable.
(3) Remove the deflector magnet and let the compass card become stable. Record
the settling value. The value must not be greater than 1
°
.
(4) Follow the procedures detailed in paragraphs (1) and (3) but turn the compass
card through -5
°
. The value must not be greater than 1
°
.
(5) Follow the procedures detailed in paragraphs (2) to (4) and test at East, South
and West positions.
PAGE 1008
APR 10/03
34-25-21
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