MIL-PRF-27197E
f. High Temperature exposure
g. Vibration tolerance
h. Magnetic effect
i. Acceleration
j. Humidity
k. Salt fog
l. Fungus
m. Overpressure
n. Seasoning
o. Pressure altitude
4.4 Test conditions. Unless otherwise specified in acquisition document (see 6.2), all
inspections shall be performed in accordance with the test conditions specified in this
specification.
4.4.1 Standard atmospheric conditions. Unless otherwise specified in the test description, tests
are to be made at ambient atmospheric pressure and temperature.
4.4.2 Tapping. Unless otherwise specified in the test description, the indicator shall be tapped
before a test reading is taken.
4.4.3 Attitude. Unless otherwise specified in the test description, the indicator shall be tested in
its normal operating position.
4.5 Requirements cross-reference matrix. Table V provides a cross-reference matrix of the
section 3 requirements tested or verified in the paragraphs below.
4.6 Tests.
4.6.1 Examination. Prior to sealing, the indicator shall be examined to determine compliance
with the materials requirement. After sealing, the indicator shall be examined for compliance
with interface and performance requirements as indicated in Table V.
4.6.2 Seal.
4.6.2.1 Case leakage. The indicator shall be mounted in an instrument panel or mock-up panel.
The pitot and static pressure connections of the indicator shall be connected to a mercury
manometer, or equivalent. A vacuum equal to 25 inches Hg (equivalent to a pressure altitude of
approximately 40,000 feet altitude) shall be applied to the pitot and static connections of the
indicator. With the connecting tubing sealed for a period of one minute, the mercury level shall
change no more than 0.01 inch.
4.6.2.2 Low temperature case leakage. The indicator shall be held at a temperature of -31oF for
3 hours. While at this temperature, the case leakage shall be conducted. The mercury level shall
change no more than 0.025 inch.
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