TB 9-4920-363-24
(a) VACUUM INCREASE and DECREASE controls as necessary to obtain
atmospheric pressure.
(b) POWER switch to OFF.
(c) VACUUM and PRESSURE selector control valves to OFF.
(d) VACUUM and PRESSURE INCREASE and DECREASE control valves
fully ccw.
Test instrument
Pneumatic pressure standard indications
indications
(ft)
(ft)
Min
Max
1000
965
1035
2000
1960
2040
4000
3950
4050
6000
5940
6060
8000
7930
8070
10,000
9920
10,080
12,000
11,910
12,090
14,000
13,900
14,100
16,000
15,890
16,110
18,000
17,880
18,120
20,000
19,870
20,130
22,000
21,860
22,140
25,000
24,845
25,155
30,000
29,820
30,180
35,000
34,795
35,205
40,0001
39,770
40,230
45,000
44,745
45,255
50,000
49,720
50,280
1Readings
above 35,000 feet are supplied in event equipment application requires greater range.
b. Adjustments
(1) Adjust TI PRESSURE INCREASE and DECREASE control valves until
pneumatic pressure standard indicates zero feet.
(2) Adjust ALT meter barometer adjustment locking screw, located at bottom left
corner of ALT meter ccw until ridge clears meter case.
CAUTION
Do not remove screw.
(3) Press ALT meter barometer adjustment locking screw to the left and turn cw to
release indicator adjuster.
(4) Adjust indicator adjuster for zero indication on ALT meter.
(5) Pull out and adjust indicator adjuster until ALT meter indicates 29.92 inHg (abs).
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