TM 55-6610-247-40
Table 3-4. Friction Tolerance
3-9. Low Temperature Scale Error Test
ALTITUDE
TOLERANCE
For a period of not less than 6 hours prior to this test,
altimeter shall not have been subjected to any test
FEET
FEET
involving operation at other than atmospheric pressures.
1,000
70
Scale error (room temperature) test shall be repeated
2,000
70
except that temperature of the altimeter during test shall
3,000
70
be approximately __35 C (__31' F). Test points shall be
5,000
70
10,000
80
those given in table 3-5. Change in scale errors of this
15,000
90
test from corresponding scale errors of room
20,000
100
temperature test shall not exceed tolerances specified in
25,000
120
30,000
140
instrument fails to meet this test, diaphragm must be
35,000
160
instrument readjusted. If the temperature compensation
adjustments are not disturbed, then the cold temperature
test is not required.
Table 3-5. Low Temperature Scale Error Test (-35C)
TEST ALTITUDE
TOLERANCE
FT
MM HG
INHG
(feet)
0
760.0
29.92
30
6,000
609.0
23.98
60
12,000
483.3
19.03
90
18,000
379.4
14.94
120
25,000
281.9
11.10
155
30,000
225.6
8.88
180
3-10. Case Leak Test.
3-11. Position Error Test
Connect static pressure connection of indicator to a
At normal atmospheric pressure, readings shall be
source of suction. Apply a suction sufficient to produce a
taken while instrument is being tapped lightly in each of
change of indication of pointers of approximately 18,000
several different positions. Change in pointer indication
feet. With source closed off during a period of 60
with change in instrument position shall not exceed 30
seconds, difference of indications shall not exceed 100
feet. If instrument fails to meet this test, it must be
feet. If a leak is indicated, check instrument and correct
adjusted for balance as described in paragraph 2-8.
for leak as described.
Change 6 3-4
