MIL-PRF-10436N
4.4.1.7.1 Instruction card. The instruction card shall be examined to verify that the
instructions are correct; the lettering is semi-gloss white (see 6.11); the card is semi-gloss green
(see 6.11) and 6 x 10 cm, nominal size; the card is water or moisture resistant; and that one
unfolded card fits in the compass carrying case. Failure of this examination constitutes failure of
this requirement.
4.4.1.8 Magnetic performance and compass error. The compass shall be placed in a
horizontal position on a fixed point and by means of the sighting mechanism, the compass shall
be sighted on three targets of known magnetic azimuths approximately 120 degrees apart. With
no remedial action by the operator, before, at, or after, a reading shall be taken at each target.
The difference between the known azimuths and readings taken is the compass error. An error
greater than 40 mils or failure of the compass to function correctly shall constitute failure of this
test.
4.4.1.9 Mechanical performance. The following tests shall be with the compass in the
operational configuration and away from all magnetic effects external to the compass.
4.4.1.9.1 Damping. The compass magnet shall be deflected 540± 20 mils from a position of
equilibrium and released. If the magnetic assembly requires more than 6 seconds to come to
rest, it shall constitute failure of this test.
4.4.1.9.2 Freedom of rotation when tilted. The compass shall be tilted 8.0 ± 0.1 degree from
the horizontal and uniformly rotated 360 degrees at approximately 10 seconds of time per
revolution, in a plane normal to the longitudinal axis of the pivot. The compass shall be rotated
one complete revolution in the clockwise direction and one complete revolution
counterclockwise. Inability of the dial or magnetic assembly to remain free while being rotated
shall constitute failure of this test.
4.4.1.9.3 Friction error. The compass dial assembly shall be magnetically deflected
40 ±5 mils by an external force acting in the horizontal plane of the compass. The mechanism
shall be permitted to come to rest. The external force shall then be removed in a radial direction
in the same horizontal plane. The compass dial shall then be read. The procedure shall be
repeated by deflecting the magnet 40 ±5 mils in the opposite direction. One-half of the
difference between the two readings is the friction error. An error greater than 20 mils shall
constitute failure of this test.
4.4.1.9.4 Illumination. The compass shall be examined to verify that the unit has light sources
for reading and sighting; the permanent magnet on the dial assembly and the bezel crystal have
light sources to aid in setting readings and sighting; and, the "E" (east) and "W" (west) markings
are illuminated. Also, verify that the light sources are self-exciting and that all sources are
recessed or flush mounted and encapsulated. Failure of this examination constitutes failure of
this requirement.
4.4.1.9.4.1 Luminosity. The assembled compass shall be examined visually for dead or dim
luminous sources, after it has been dark adapted for not less than 1 hour. The spectral and
luminescent output shall be visually compared to a compass used to establish the working
standards (see 6.2.1). Sources of questionable luminosity shall be retested. All subsequent
brightness tests shall be determined by a photoelectric photometry method, corrected for
photopic vision, using a photometer calibrated to the working standards. If the brightness of the
luminous sources of the assembled compass is not sufficient to perform all compass functions in
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