MIL-DTL-24784/18B (SH)
operation of the equipment. This provision shall apply, for example, to unique features and
concepts of self-checking and automatic test programming features of equipment. The text shall
be supported with block diagrams. The number of diagrams required for clarity depends upon the
variety of outputs and the changes imposed by different operational modes. When summary
troubleshooting block diagrams are contained in the fault-isolation portion of the manual,
appropriate references shall be made to avoid redundancy.
3.6.4.2 Detailed functional description. The detailed functional description shall begin with a
detailed block diagram presentation of each major functional block presented in the general
functional description. The presentation shall clearly indicate what group of signals covered in the
general functional description is being expanded in the detailed functional description. For
example, data flow on the general functional block diagram should be expanded into individual
signals and the generation path of the individual signals further expanded into a detailed block
diagram. Figure 18-8 is a typical example of this technique. Outputs shall be identified by names
or fire control symbols. Diagrams that are redundant, in total or in part, with troubleshooting
diagrams contained in the fault-isolation portion of the manual shall not be included.
3.6.4.2.1 Troubleshooting diagrams. The troubleshooting diagrams in the fault-isolation portion
of the manual shall be used in the detailed functional description as the basic supporting
illustrations. Diagram titles shall be synonymous with the heading titles.
a. The description shall first briefly describe the composition of the output by tracing the output
back to its origin. This will illustrate functional dependency of the circuits or mechanisms and
will familiarize the technician with the way in which the signal flow diagram and associated
pyramid diagram, when required, are to be used for fault-isolation. It also provides the
technician with a summary of the total generation path as background for the more detailed
description that will follow.
b. Next, the text shall, in effect, "talk through" each of the signal flow diagrams from source to
output. These presentations shall be supplemented, as required for completeness, by reference
to second-order supporting diagrams contained in the fault-isolation portion of the manual.
As required for clarity, additional supporting illustrations shall be provided. These may
include timing diagrams or a block diagram giving a more condensed view of a particularly
complex signal flow diagram (see MIL-DTL-24784). Such additional illustrations shall be
consistent with the troubleshooting diagrams with respect to nomenclature, symbology, and
reference designations. These diagrams shall clearly label and define source and destination
input and output signals and mechanical occurrences, and the time and phase relationships.
3.6.4.2.2 Functional elements. Functional elements consisting of electrical, electronic,
pneumatic, hydraulic, mechanical, and optical units, shall be described in sufficient detail to
provide the technician with a complete under- standing of how these elements accomplish their
functions. Depth of coverage, which may be defined as detailed circuit analysis or mechanical
analysis, shall be restricted to areas of new or unusual design. Descriptions of conventional
circuits or devices that are covered in Navy Class A training generally shall not be extended below
the level of single function stages or individual active elements; for example, amplifier stage,
10
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business