44
Checking and correcting the reference position
Check whether the reference position is correct if altitude or compass indication is
incorrect even after calibration.
What is the reference position?
The base position of hands to indicate
altitude and compass direction.
•Position of the 10 000 ft hand: 6:00
•Position of the 1 000 ft hand (compass
hand): 12:00
•Position of the 25 ft hand: 12:00
•The hour, minute and second hands do
not have the reference position.
Correct reference positions
+
-
x 10000 ft.
ft.
0
2000
-1000
8000
4000
6000
0
1
2
3
W
E
ft.
(-100)
(-200)
(-300)
(-400)
(-500)
(-600)
(-700)
(-800)
(-900)
0
500
900
400
800
300
700
200
600
100
1
0
0
(
-
9
0
0
)
(
+
5
0
0
)
S
(
-
5
0
0
)
f
t
.
W
E
6
0
0
(
-
4
0
0
)
7
0
0
(
-
3
0
0
)
8
0
0
(
-
2
0
0
)
9
0
0
(
-
1
0
0
)
2
0
0
(
-
8
0
0
)
3
0
0
(
-
7
0
0
)
4
0
0
(
-
6
0
0
)