MIL-DTL-25866C
4.4.2 Circuit conditions. The test specimen shall be equipped with a PR-2 flashlight
lamp, batteries, and unless otherwise specified, 28 VDC shall be applied to the power-failure
relay when the light is subjected to tests which require functional operation of the light.
4.5 Test methods.
4.5.1 Examination of product. The light shall be inspected to determine compliance with
the requirements specified herein with respect to materials, workmanship, dimensions, and
marking.
4.5.1.1 Switch operation. The light, with lamp and batteries installed, shall be inspected
for functional operation of inertia switch and reset, manual switch, and for the proper operation
of the relay or other device that energizes the light when aircraft electrical power is off.
4.5.2 Environmental tests.
4.5.2.1 High temperature. The complete light with batteries installed shall be subjected
to high temperature in accordance with MIL-STD-810, method 501, procedure III, at a
temperature of 160 ±3.6 °F (71 ±2 °C), dry heat, for a period of 4 hours, followed by an
operational test of the manual switch, and proper operation of the relay, or other device, which
energizes the light when aircraft electrical power is lost. This test shall be conducted while at
the high temperature. At the end of the tests, the light shall be removed from the test chamber
and examined. There shall be no crazing, dimensional changes, or other defects. The light shall
be returned to room temperature and checked for proper operation.
4.5.2.2 Low temperature. The complete light with batteries installed shall be subjected
to low temperature in accordance with MIL-STD-810, method 502, procedure II, at a
temperature of -65 ±3.6 °F (-54 ±2 °C), for a period of 4 hours, followed by an operational test
of the manual switch, and proper operation of the relay, or other device, which energizes the
light when aircraft electrical power is lost. This test shall be conducted while at the low
temperature. At the end of the tests, the light shall be removed from the test chamber and
examined. There shall be no crazing, dimensional changes, or other defects. The light shall be
returned to room temperature and checked for proper operation.
4.5.2.3 Altitude. The assembly shall be subjected to an altitude test in accordance with
MIL-STD-810, method 500, procedure II, at an altitude of 20,000 feet, a temperature of
32 °F (0 °C), for a period of 4 hours, followed by an operational test of the manual switch, and
proper operation of the relay, or other device, which energizes the light when aircraft electrical
power is lost. This test shall be conducted while at the altitude and temperature conditions
listed. At the end of the tests the light shall be removed from the test chamber and examined.
There shall be no crazing, dimensional changes, or other defects. The light shall be returned to
room temperature and checked for proper operation.
4.5.2.4 Humidity. The light shall be subjected to the humidity test in accordance with
MIL-STD-810, method 507, procedure II, except that the test conditions shall be maintained
only for a 72-hour period. The assembly shall not be adversely affected by the test. The lamp
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