A. This diagram is similar to a shipboard isometric
wiring diagram.
The simplified wiring diagram (fig. 6-6, view B)
may be further broken down into various circuit
wiring diagrams showing in detail how each
component is connected into the system. Circuit
wiring diagrams show equipment part numbers, wire
numbers, and all terminal strips and plugs just as they
do on shipboard wiring diagrams.
Aircraft Wire Identification
Coding
All aircraft wiring is identified on the wiring
diagrams exactly as marked in the aircraft. Each wire
is coded by a combination of letters and numbers
imprinted at prescribed intervals along the run. You
need to look at figure 6-7 as you read the following
paragraphs.
The unit number shown dashed (fig. 6-7) is used
only in those cases where more that one identical unit
is installed in an identical manner in the same aircraft.
The wiring for the first such unit would bear the prefix
1, the second unit the prefix 2, and so on. The rest of
the designation remains the same in both units.
The circuit function letter identifies the basic
function of the unit concerned according to the codes
shown in figure 6-8. Note the dashed L after the circuit
function R in figure 6-7. On R, S, and T wiring, this
letter designates a further breakdown of the circuit.
Figure 6-7.—Aircrafl wire identification.
Circuit
function
letter
A
B
C
D
E
F
G
H
J
K
L
M
P
Q
R
S
T
V
W
X
Y
Circuits
Armament
Photographic
Control surface
Instrument
Engine instrument
Flight instrument
Landing gear
Heating, ventilating, and deicing
Ignition
Engine control
Lighting
Miscellaneous
DC power — Wiring in the dc
power or power control system
will be identified by the circuit
function letter P.
Fuel and oil
Radio (navigation and
communication)
RN-Navigation
RP-Intercommunications
RZ-Interphone, headphone
Radar
SA-Altimeter
SN-Navigation
SQ-Track
SR-Recorder
SS-Search
Special electronic
TE-Countermeasures
TN-Navigation
TR-Rece ivers
TX-Television transmitters
TZ-Computer
DC power and dc control wires
for ac systems will be
identified by the circuit
function letter V.
Warning and emergency
AC power
Wiring in the ac power
system will be identified by the
circuit function letter X.
Armament special systems
Figure 6-8.—Aircraft wiring, circuit function code.
6-10
