chapter 3 — circuit, component, wire, cable, and harness

BHT-ELEC-SPM

3-00-00

ECCN EAR99

TABLE OF CONTENTS

Paragraph Chapter/Section Page Number Title Number Number

CHAPTER 3 — CIRCUIT, COMPONENT, WIRE, CABLE, AND HARNESS DESIGNATIONS

CIRCUIT, COMPONENT, WIRE, AND CABLE HARNESS DESIGNATIONS

3-1 General Information................................................................... 3-00-00 33-2 Wiring Identification Code.......................................................... 3-00-00 33-3 Wiring Harness and Cable Designation..................................... 3-00-00 33-4 Component Symbols ................................................................. 3-00-00 53-5 Electrical Components and Assemblies —

Reference Designator Assignment ............................................ 3-00-00 173-6 Resistor Characteristic Codes ................................................... 3-00-00 24

FIGURES

Figure PageNumber Title Number

3-1 Wire Identification Code ................................................................................. 43-2 Circuit Identification ........................................................................................ 63-3 Component Symbols — Typical ..................................................................... 73-4 Reference Designator..................................................................................... 233-5 Typical Film Resistor Color Codes ................................................................. 26

TABLES

Table PageNumber Title Number

3-1 Circuit Functions............................................................................................. 53-2 Reference Designator — System Number and Description (Typical)............. 173-3 Reference Designator — Unit Number and Item Number Letter Codes

(Typical) .......................................................................................................... 213-4 Electrical and Electronic Components, Reference

Designator/Description/Location — Reference Table (Examples) ................. 223-5 Film Type Resistor Color Codes .................................................................... 243-6 RE Type Resistance Code ............................................................................. 273-7 RER Type Resistance Code........................................................................... 283-8 RWR Type Resistance Code.......................................................................... 29

27 MAY 2011 Rev. 1 /2

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

CIRCUIT, COMPONENT, WIRE, CABLE, AND HARNESS DESIGNATIONS

3-1. GENERAL INFORMATION

This chapter includes information necessary tounderstand the identification of the wires, cables,harnesses, components, and circuits. Each wire,cable, and cable harness is physically marked foridentification on wiring diagrams and schematics.Wiring diagrams and schematics also use symbols toidentify the type of electrical components within asystem or circuit.

Each electrical component has a reference designatorconsisting of a system number, unit number, and anitem number, when applicable, for identification onschematics and wiring diagrams.

Resistors are employed in some circuits for voltagereduction and/or biasing. Information to identify thevalue, tolerance, and method of attachment is alsoprovided.

3-2. WIRING IDENTIFICATION CODE

NOTE

It is not necessary to mark wires and cablesthat are shorter than 6 inches (15.2 cm) inlength.

Each wire is stamped with a coded designationapproximately 10 inches (25.4 cm) apart along theentire length (Figure 3-1). The code identifies thecircuit function, wire number of that circuit, thesegment of a specific wire number, wire size, and ifapplicable, ground.

1. In most cases, the circuit function is the first letteror letters in the code. Refer to Table 3-1 for circuitidentification. In the event there are two or moreidentical items or equipment installed on the samehelicopter, a system or unit number is used as a prefixto the circuit function letter. For example, systemnumber 1 can be used to designate the copilot or left

side system and system number 2 to designate thesame equipment for the pilot or right side system.

NOTE

Some customizing installations may useadditional codes not listed in Table 3-1.

2. The next designation is the wire number for aparticular circuit. This number identifies the completewire run between two components. Typically, it ispower from a source or bus to the controllingcomponent or a wire from the controlling component toan actuator, motor, or indicator (Figure 3-2).

3. Each segment of a wire number is markedstarting with the letter A at the power or control source.Each time that wire number is interrupted by a terminalboard, connector, etc., the wire segment letter isadvanced to the next letter in alphabetical sequence(Figure 3-2).

4. Wire size number denotes the wire size toAmerican Wire Gauge (AWG) standards.

5. Ground letter notation (N) designates a wire aspart of a ground circuit.

3-3. WIRING HARNESS AND CABLEDESIGNATION

Wiring harness and cable assembly identification ismarked by part number on a white teflon sleeve ormarking label placed within 3 inches (7.6 cm) of theterminating connector (Figure 3-2).

On some helicopters, each harness is also assigned aunique wire harness identification code. Thisalphanumeric code starts with a W. The wire harnessW-code (e.g., W5A) can be found on the harnessidentification label (Figure 3-2). The harnessidentification is installed every 36 to 48 inches (914 to1219 mm) along the harness.

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

Figure 3-1. Wire Identification Code

ELEC-SPM_ch03_0001

L 18 A 20 N

2 A U D 37 A 20 N

GROUND LETTER

WIRE SIZE NUMBER

WIRE SEGMENT LETTER

WIRE NUMBER

CIRCUIT FUNCTION LETTER

SYSTEM (UNIT) NUMBER

GROUND LETTER

WIRE SIZE NUMBER

WIRE SEGMENT LETTER

WIRE NUMBER

CIRCUIT FUNCTION LETTER

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

3-4. COMPONENT SYMBOLS

Components are identified on schematics and wiringdiagrams by symbols illustrated in Figure 3-3. Thesesymbols are typical. Refer to the wiring diagramchapter in the Maintenance Manual for model specificsymbols.

Table 3-1. Circuit Functions

CODE NOMENCLATURE

ADF Automatic Direction Finder

ALT or

ALTM

Radio (Radar) Altimeter

ARC UHF Communication

ATC Air Traffic Control

AUD Interphone

C Control Surfaces

COMM Communication

D Instruments (other than flight or engine)

DME Distance Measuring Equipment

E Engine Instruments

F Flight Instruments

FL Electrical Filter

G Landing Gear

GPS Global Positioning System

GYRO Gyromagnetic Compass

H Heating, Ventilating, and De-icing

J Ignition

K Engine Control

L Lighting

M Miscellaneous Electric

MKR or

MB

Marker Beacon

N Ground

NAV Navigation

P DC Power

Q Fuel and Oil

R Radio (navigation and communication)

RD Direction Finder

RF VHF Liaison

RL HF Communication

RM Marker Beacon

RN Navigation

RU UHF Command

RV VHF Command

RZ Interphone and Headphone

S Radar

SX IFF Transponder

T Special Electronics

TCS Traffic Collision and Avoidance System

V DC Power and DC Control Cables for

AC System

VHF VHF Communication

W Warning and Emergency

X AC Power

XPDR Transponder

Table 3-1. Circuit Functions (Cont)

CODE NOMENCLATURE

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

Figure 3-2. Circuit Identification

ELEC-SPM_ch03_0002

CABLE ASSEMBLY(429-079-101)

2150B1

AVIONIC BLOWERLCTN - PEDESTAL

M

3

HEATER

FAULT SIGNAL

2150B1P1

4

28 VDC1GROUND2

H014A24

3940A1

3940A1J1 3940A1P1

H004A22

FWD CB PANEL LHLCTN - PEDESTAL LH

F2 A

2150CB1

AVIONICBLOWER

28 VDC ESS 1BUS

H004B22 WHTH004B22 BLU

2150GD3DC GND 1

2150GC1CHASSIS GND 1H017A22N

H018A22N

WIRE SIZE

WIRE SEGMENT LETTER

WIRE NUMBER

CIRCUIT FUNCTION

COMPONENT SYMBOL

429-079-101-XXX CABLE ASSEMBLY

GROUND DESIGNATION

REFERENCE DESIGNATOR

HARNESS IDENTIFICATION LABEL

EXAMPLEHARNESS IDENTIFICATION LABEL

2150B1P1AVIONIC BLOWER 3.0 IN.

(7.6 cm)

2150B1P1AVIONIC BLOWER

W101429-079-101

WIRING ASSEMBLY(AVIONIC BLOWER)

OR

A white shrink sleeve tubing positioned every 36 to 48 inches (91.4 to 121.9 cm) along the harness may also be utilized.

NOTE

CONNECTORIDENTIFICATION (2150B1P1)

1

1

HARNESS IDENTIFICATIONCODE (W101)

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

Figure 3-3. Component Symbols — Typical (Sheet 1 of 10)

ANTENNAS

CONNECTORS

ADF LOOP

MARKER BEACON

RADAR ALTIMETER LOOP

COAX

RESISTOR MODULE

1J3 1P3

J = JACK (RECEPTACLE)P = PLUG (CONNECTOR)

RECEPTACLEAND PLUG

QUICKDISCONNECT

PERMANENTSPLICE

TERMINAL JUNCTION(TYPICAL)

TERMINAL CONNECT

HF TERMINAL BOARDS AND BLOCKS

STUD TYPEMODULE

BUSSEDPOSITIONS

1

B

A

C

2

3

A1

B1

C1

F1

G1

H1

ADF SENSE

SENSE FM COMM (WHIP) HOMING

VHF AM TRANSPONDERRH HALF

VOR

LH HALF

DME, UHF/VHF ANDTRANSPONDER

A

B

F

G

C

D

H

J

E K

ELEC-SPM_ch03_0003a

ABCDE

GHJK

FMAMCMEMG

MDMFMH

MB

21

ANTENNAS (TYPICAL) COUPLER

GROUND MODULE

IN LINE CONNECTOR

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99


INSTRUMENTS

INDICATOR AND CONNECTOR

IND

AMMETER (LOADMETER)

FIRE DETECTOR ELEMENT

TEMP BULB

STATIC PORT HEATER

ELEC-SPM_ch03_0003b

PITOT HEATER

VOLTMETER

L+

-

B

A

B

A

C

HOUR METER

+

–V

TEMPERATURECONTROLLER

FIREA

FAIL

B

CDE

SENSOR PRESS

ABC

AB

CHIP DETECTOR

BA

C

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99


LIGHTS

R

NAVIGATION LIGHT COCKPIT LIGHT

ELEC-SPM_ch03_0003c

A

2

3

4

1

5

L L

LL

L

C

B

A

L

L

G

3

1

2

L

L

SEARCHLIGHT LANDING LIGHT

1

2

3

4

WARNING LIGHT

PRESS TO TEST AND INDICATORFIRE PULL HANDLE(MAIN & RESERVE)ANTICOLLISION LIGHT

LIGHTINGPOWER SUPPLYDOME LIGHT

W

R

MASTER WARNING LIGHT

1 A

E23

DABE

A

W

G

C

–

+

2

31

ENG OUT

S-RED

4–

+

W

INCANDESCENT LAMP CHART LIGHT

PANEL LIGHT

LED ANNUNCIATOR

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99


RELAYS

ELEC-SPM_ch03_0003d

SINGLE POLE/SINGLE THROW

PLUG-IN RELAY POWER RELAY RCCB RELAY

BATTERY RELAY

SINGLE POLE/DOUBLE THROW

X1 X2

A1 A2

DOUBLE POLE/DOUBLE THROW

B2X1

X2

A2

B1

A1

X1

X2

A1

A2

A3

B1B2

B3

DOUBLE POLE/DOUBLE THROW (DELAY)

E

K

A

B

H

F

CG

D

1113

1

14

2

12

H

A

X1

X2

A1 A2

3

S1S2

S3

5A

5B

BUS

COILCONTROL

A1

A2

CURRENTLEVEL AND

SENSETIMER

SWITCHRESET RST

SW

1314

OVRD

X1

X2

A1

B1B2B3

A2A3

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99


POWER COMPONENTS

ELEC-SPM_ch03_0003e

CAPACITOR CIRCUIT BREAKER

EXTERNAL POWER RECEPTACLE

STARTER GENERATOR

A

E

TRANSISTOR

B

C ENPN

FUSE

INVERTER

M

BUS BAR

VOLTAGE REGULATOR

TRANSFORMER(STEP UP OR DOWN)

- +A1

PUSH SWITCH

PUSH PULLREMOTE CONTROL

A2

A3

–

+

+

C B D A

X2X1

B

C EPNP

CURRENTTRANSFORMER

+–

5

ARM

A

D

E

B

C

A

CB

–

+

+

GENERATOR REGULATORCONTROL UNIT SHUNT

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99


POWER COMPONENTS

ELEC-SPM_ch03_0003f

VALVEINTERCONNECT VALVE

SHUT-OFF VALVE

BATTERY

BATTERY

–

–+

+

A

C

B

D

E

A

+

A

–

BCD

MOPEN

CLOSE

GF

E

BD

CA

PMM

CLOSE

OPEN

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99


SWITCHES

ELEC-SPM_ch03_0003g

PUSH-ONPUSH-OFF SWITCH


SINGLE POLE/DOUBLE THROW (ALTERNATE ACTION)


(MOMENTARY ACTION)

CENTER SINGLE POLE/SINGLE THROW RELAY

THERMALSWITCH

DOUBLE POLE/DOUBLE THROW-INDEPENDENT

NO NO NO C C

INCR DECR

FOOT SWITCHRESET SWITCH

OVERHEAT SWITCH

PRESSURE SWITCH SELECTOR SWITCH

FOUR POSITION SWITCH

DOWN

UP

LEFT RIGHT

OFF

15

13 17

181112

1614

B

A

PUSH BUTTON SWITCH POTENTIOMETER (CONTROLS VOLTAGE) RHEOSTAT (CONTROLS CURRENT)

NORMALLY CLOSED

NORMALLY OPEN

A1A2A3

EXTEND/ON

RETRACT/STOW

LEFT RIGHT

A

CB

NCCOM

NO

P

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99


SWITCHES

ELEC-SPM_ch03_0003h

INERTIA SWITCH

SWITCH/LIGHT ROTARY KNOB ROTARY SWITCH

MAGNETICALLY HELD SWITCH MOMENTARY PUSH SWITCH NORMALLY CLOSED

GOV RPM SWITCH TEST SWITCH MOMENTARY SWITCH

NC

PTT

NO

C

NC

NO

C

ENG 1

ENG 2

OEI TRNG

HIGH

LOW

STOP54

3

21 INT

C1

OFF/MANUALENABLE

A13

24

B13

24

PUSHTO TEST

ON

OFF

NOC

NC

7

1098

65

111213141516

TRIMON

B

3A2

1

7

8

2

645

13

2

3

1

4

5

6

7

OFF

DIM

BRT

24

13

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99


MISCELLANEOUS

ELEC-SPM_ch03_0003i

STRUCTURAL GROUND

END CAP DIODE

ZENER DIODE

CATHODE –ANODE +

PUMP RESISTOR PANEL LIGHT PLUGHOLDING

COIL

R_

_

FUEL QUANTITY CONNECTORS SOLENOID VALVE

FUELCELL(TYP)

ENGINE VIB. METER RECPT SHIELDED WIRES IN CABLE

(TRIPLE) (PAIR)

T

INDUCTORS

AIR CORE IRON CORE

THERMOCOUPLE HARNESS

RECEIVERTRANSMITTER

CONTROLS

HEATED BLANKETRECEPTACLE

–+

–+

B

AUNITCOUPLER

(TYP) D

A

P

+

–

RED

BLUE

SHIELDED SINGLE

COAXIAL CABLE

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99


MISCELLANEOUS

ELEC-SPM_ch03_0003j

MISCELLANEOUS EQUIPMENT FIRE EXTINGUISHER CARTRIDGE

THERMISTOR TEMPERATURE SENSOR

INDICATOR PANEL

HORN OR LOUDSPEAKER HEADSET MICROPHONE

B

A

D

C

B

A

A

CB

+–

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

3-5. ELECTRICAL COMPONENTS ANDASSEMBLIES — REFERENCEDESIGNATOR ASSIGNMENT

Each electrical component and assembly is assignedan alphanumeric code on the wiring diagrams andschematics called a reference designator (Figure 3-4).

The reference designator consists of a system number(Table 3-2) and unit number (Table 3-3) foridentification. Item numbers (Table 3-3) are also usedat the end of the reference designator to identify an

item such as a connector, which connects to theparticular reference designator.

Components are identified by their referencedesignator on the electrical schematics, wiringdiagrams, and by a decal or label adjacent to theirinstalled location on the helicopter. Table 3-4 providesan example of a reference designator listing that maybe provided in some Maintenance Manuals.

The Index of Reference Designator listing provided inIllustrated Parts Breakdown Manuals (IPB) may alsobe used to identify the installed location of thecomponent as well as its part number.

Table 3-2. Reference Designator — System Number and Description (Typical)

SYSTEM NUMBER

SYSTEM DESCRIPTION

1 Propulsion and Fuel Systems

2 DC Power System, Start and

Ignition System

4 Instruments Panels and Console

6 Flight Controls

8 Light Systems

9 Flight Control Hydraulic System

10 Environmental Control Systems

24 Float, Cargo Hook, and

Miscellaneous Kits

2100 Air Conditioning — General

2140 Heating System

2150 Cooling System

2160 Temperature control

2200 Autopilot System — General

2210 Autopilot System

2220 Autopilot Speed — Attitude

Correction

2230 Autopilot Auto Throttle

11

2240 Autopilot System Monitor

2300 Communications System —

General

2310 Communications — (HF)

2320 Communications — (VHF)

2321 Communications — (ELT)

2330 Communications — Passenger

Address and Entertainment

2340 Communications — Interphone

2350 Communications — Audio

Integrating

2360 Communications — Static

Dissipation

2370 Communications — Audio and

Video

2400 Electrical Power System —

General

2420 AC Generation System

2430 DC Generator Power System

2440 External DC Power System

Table 3-2. Reference Designator — System Number and Description (Typical) (Cont)

SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

2450 Electrical Power — Electrical

Load Distribution

2500 Equipment — General

2510 Equipment — Flight Compartment

2520 Equipment — Passenger

Compartment

2560 Equipment — Emergency

2580 Equipment — Cargo Hook

2581 Equipment — External Hoist

2600 Fire Protection System —

General

2610 Fire Detection System

2620 Fire Extinguishing System

2700 Flight Control System — General

2701 Flight Control System — Copilot

Collective

2702 Flight Control System — Pilot

Collective

2703 Flight Control System — Copilot

Cyclic Grip

2704 Flight Control System — Pilot

Cyclic Grip

2720 Flight Control System —

Collective Position Sensor

2800 Fuel System — General

2810 Fuel System — Storage

2820 Fuel Balance System — Control/

Distribution

2840 Fuel System — Fuel Gauging/

Indicating

2900 Hydraulic Power — General

2910 Hydraulic Power — Main System


SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

2930 Hydraulic Power — Indicating

3000 Ice and Rain Protection System

— General


— Pitot and Static


— Windows and Windshield


— Rotors and Prop Rotors


— Detection

3100 Indicating/Recording System —

General


Recorders/Data Acquisition


Central Computer


Central Warning


Central Display System


Aircraft Data Interface Unit (ADIU)

3200 Landing Gear System — General

3210 Landing Gear System — Main

Gear and Doors

3220 Landing Gear System — Nose

Gear and Doors

3230 Landing Gear System —

Extension and Retraction

3240 Landing Gear System — Wheels

and Brakes

3260 Landing Gear System — Position

and Warning


SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

3300 Lighting System — General

3310 Lighting System — Flight

Compartment

3320 Lighting System — Passenger

Compartment

3340 Lighting System — Exterior

3347 Lighting System — Searchlight

3380 Lighting System — Emergency

3400 Navigation System — General

3406 Navigation System — ADF

3407 Navigation System — ADAHRS

3410 Navigation System — Flight

Environment Data

3420 Navigation System — Attitude

and Direction

3421 Navigation System — Weather

Radar

3427 Navigation System —

Transponder, Encoding Altimeter

3440 Navigation System — TCAS

3450 Navigation System — GPS

3460 Navigation System — Display

Unit Heater

3470 Navigation System — Course

Heading Flight Director Panel

(CHFD)

3900 Electrical/Electronic Panels and

Components — General


Components — Instruments and

Control Panels


Components — Equipment Racks


SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

3930 Electrical/Electronic Components

— Junction Boxes and Relay

Panels


Components — Multipurpose

Electronics Components


Components — Terminal Module


Components — Ground Module


Components — Integrated

Circuits


Components — Printed Circuit

Card Assemblies

4296 Integrated Avionics System

4350 Pilot Headset

5200 Doors — General

5270 Door Warning

6500 Rotor System — General

6510 Rotor System — Main Rotor

6520 Rotor System — Anti-torque

Rotor Assembly

6530 Rotor System — Accessory

Drives/Gearboxes

6540 Rotor System — Controlling

6550 Rotor System — Braking

6560 Rotor System — Indicating

7100 Power Plant System — General

7150 Power Plant System — Electrical

Harness


SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

7160 Power Plant System — Inlet

Barrier Filter

7200 Engine — General

7300 Engine Fuel and Control System

— General


— Controlling


— Indicating

7400 Ignition — General

7410 Ignition — Electrical Power

Supply

7420 Ignition — Distribution

7500 Air — General

7510 Air — Engine Anti-icing

7540 Air — Indicating

7700 Engine Indicating — General

7710 Engine Indicating — Power

7720 Engine Indicating — Temperature


SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

7900 Oil — General

7930 Oil — Indicating

8000 Engine Start System — General

8010 Engine Start System — Cranking

9500 Crew Escape and Safety —

General

9560 Crew Escape and Safety —

Flotation

9900 Surveillance — Articulated

Landing Light

NOTE:

The listing provided is typical and is

primarily based on DOD-STD-863B. Due to

differing system number and descriptions

used in the past, refer to the specific

helicopter model Maintenance Manual for

additional information.


SYSTEM NUMBER

SYSTEM DESCRIPTION1

1

1

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

Table 3-3. Reference Designator — Unit Number and Item Number Letter Codes (Typical)

LETTER CODE

CLASS OF COMPONENT

A Electronic or Electrical Assembly,

Control Panel, Fuel Probe

AT Electrical or Electronic Termination

B Electrical Driven Pump, Blower, Fan

BT Battery, Battery Cell

C Capacitor

CB Circuit Breaker

CM Computer

CP Control Panel (avionics), Coupler

Connector, Adapter (electrical)

CR Diode, Diode Assembly

CT Course Heading Flight Director Panel

(CHFD)

D Light

DS Light Assembly (electrical), Indicator

(avionics), Alarm, Annunciator

E Chip Detector (electrical), Fire

Detection Element, Temperature

Probe, Igniter, Antenna (avionics)

F Fuse

G Pressure Transducer, Accelerometer

HR Heater

J Electrical Receptacle

K Relay, Contactor

L Solenoid, Searchlight

LS Speaker, Warning Horn

M Indicator, Clock

MG Starter Generator

MP Directional Gyroscope

MT Sensor, Transducer

ND Ground Assembly

P Electrical Connector

PS Power Supply

Q Transistor

R Resistor, Shunt

RE Receiver (avionics)

RT Resistive Temperature Bulb

S Switch

T Transducer

TB Terminal Block

TC Thermocouple

TR Transceiver (avionics), Magnetometer

TX Transmitter (avionics)

VR Voltage Regulator, Generator

Regulator Control Unit (GRCU)

WTB Junction Module

WTD Ground Module

XK Relay Mount Socket

Z Fuel Signal Conditioner

Table 3-3. Reference Designator — Unit Number and Item Number Letter Codes (Typical) (Cont)

LETTER CODE

CLASS OF COMPONENT

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

Table 3-4. Electrical and Electronic Components, Reference Designator/Description/Location —Reference Table (Examples)

REFERENCE DESIGNATOR

COMPONENT DESCRIPTION LOCATIONFIGURE SHEET

LOCATION

407 MAINTENANCE MANUAL EXAMPLE

2S1 Switch, BATT Switch Overhead Console Sheet 11

2S2 Switch, GEN RESET Switch Overhead Console Sheet 11

2TB1 Terminal Board (junction block) Overhead Console Sheets 11 and 14

2VR1 Voltage Regulator FS 160.0, LBL 20.0, WL 52.0 Sheets 16 and 20

2VR1P1 Connector, Voltage Regulator FS 160.0, LBL 20.0, WL 52.0 Sheets 16 and 20

2XK4 Relay Socket, Field/Igniter Relay FS 166.0, DC Equipment Panel Sheet 20

3CB1 Toggle Circuit Breaker 30 amps,

OFF AVIONICS MASTER (kit)

Overhead Console Sheet 11

3J1 Receptacle, DC Power Panel FS 155.0, WL 60.0, Right Side Sheet 16

3P1 Connector, DC Power Panel FS 155.0, WL 60.0, Right Side Sheet 16

4A1 Switch Box, Collective Collective Sheet 8

412 MAINTENANCE MANUAL EXAMPLE

1A1 Engine and Fuel Control Panel

1A1P1 Connector

1A1P2 Connector

1A1K1 Fuel Crossfeed Relay

1A1S1 Engine 1 Fuel Switch

1A1S2 Engine 2 Fuel Switch

1A1S3 Engine 1 Gov Switch

1A1S4 Engine 2 Gov Switch

1A1S5 Engine 1 Boost Pump Switch

1A1S6 Engine 2 Boost Pump Switch

1A1S7 Fuel Intcon Switch

1A1S8 Fuel Crossfeed Switch

1A1S9 Fuel Intcon/Crossfeed Switch

1A1S12 Engine 1 Fuel Transfer Switch

1A1S13 Engine 1 Fuel Transfer Switch

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

Figure 3-4. Reference Designator

ELEC-SPM_ch03_0009

SYSTEM NUMBER(LIGHTING)

8DS3J1

UNIT NUMBERDS-LIGHT ASSEMBLY3-3RD ASSEMBLY

ITEM NUMBERJ-CONNECTOR, RECEPTACLE1-CONNECTOR NO.1(CERTAIN UNITS CAN HAVEMORE THAN ONE CONNECTOR.IN THIS CASE THEY WOULD BEIDENTIFIED J2, J3, ETC.)

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

3-6. RESISTOR CHARACTERISTIC CODES

For film type resistors Table 3-5 will identify theresistance in ohms, tolerance and type of attachment.Refer to Figure 3-5 for typical film resistor color codes.RE, RER, and RWR type codes are explained inTable 3-6 through Table 3-8 respectively.

Table 3-5. Film Type Resistor Color Codes

BAND A BAND B BAND C BAND D BAND E BAND F

Color

Firs

t sig

nifi

cant

num

ber

Color

Sec

ond

sig

nific

ant

num

ber

Color

Thi

rd s

ign

ifica

nt

num

ber

ColorM

ulti

plie

rColor

Res

ista

nce

Tole

ranc

e

(per

cent

)

Color

Sol

der

able

Ter

min

al

Silver Silver Silver Silver 10-2

(x 0.01)

Silver ±10% White

Yes

Gold Gold Gold Gold 10-1

(x 0.1)

Gold ±5% No Band

No

Black 0 Black 0 Black 0 Black 1

Brown 1 Brown 1 Brown 1 Brown 10 Brown ±1%

Red 2 Red 2 Red 2 Red 102 Red ±2%

Orange 3 Orange 3 Orange 3 Orange 103

Yellow 4 Yellow 4 Yellow 4 Yellow 104

Green 5 Green 5 Green 5 Green 105 Green ±0.5%

Blue 6 Blue 6 Blue 6 Blue 106 Blue ±0.25%

Violet 7 Violet 7 Violet 7 Violet 107 Violet ±0.10%

Gray 8 Gray 8 Gray 8 Gray 108 Gray ±0.05%

White 9 White 9 White 9 White No

Color

±20%

1

2 3 4 5 6 7

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

Table 3-5. Film Type Resistor Color Codes (Cont)

NOTES:

Example of color coding 5100 ohms ±1%, solderable leads.

Band A — green; Band B — Brown; Band C — Black; Band D — Brown; Band E — Brown; Band F — White

The first significant number of the resistance value.

The second significant number of the resistance value.

The third significant number of the resistance value. This significant number is only applicable to

resistors with a 5-band coding (Figure 3-5).

The multiplier (the multiplier is the factor by which the significant numbers are multiplied to yield the

nominal resistance value).

The resistance tolerance.

Indicates a solderable terminal and has a white indicator band. This band is approximately 1.5 times the

width of other bands. This band is only applicable to resistors with military specifications. Commercial

resistors may have a band indicating the temperature coefficient or resistor reliability.

1

2

3

4

5

6

7

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

Figure 3-5. Typical Film Resistor Color Codes

ELEC-SPM_ch03_0010

1

TOLERANCE ≥2%

2 4 5

1TOLERANCE ≤1%

2 3 4 5

6

BAND ABAND B

BAND CBAND D

BAND E

BAND ABAND B

BAND FBAND DBAND E

1.2.3.4.5.6.

1st significant figure2nd significant figure3rd significant figureMultiplierResistance toleranceSolderable terminal

1 Refer to Table 3-5 for additionnal information.

NOTE

FOUR BAND CODE EXAMPLES

Green, blue, red, with silver tolerance band: 56 x 100 = 5.6 ohms, with a tolerance of 10%, white band for solderable terminals.

Red, red, brown, silver tolerance band: 22 x 10 = 220 ohms (220 ohms), with a tolerance of 10%.

Brown, black, orange, gold tolerance band: 10 x 1000 = 10000 ohms (or 10K ohms), with a tolerance of 5%.

FIVE BAND CODE EXAMPLES

Red, red, brown, black, with a brown tolerance band: 221 x 1 = 221 ohms, with a tolerance of 1%, white band for solderable terminals.

Blue, brown, white, brown, green tolerance band: 619 x 10 = 6190 ohms (6.19K ohms), with a tolerance of 0.5%.

Brown, black, black, red, with a brown tolerance band: 100 x 100 = 10000 ohms (10.0K), with a tolerance of 1%.

1

1

4 BAND

(ONLY SHOWN WHEN RESISTORHAS SOLDERABLE TERMINALS)

5 BAND

BHT-ELEC-SPM

3-00-0027 MAY 2011 Rev. 1 ECCN EAR99

Table 3-6. RE Type Resistance Code

RE77 G 1001

Style: The two-letter symbol RE identifies chassis-mounted, power type,

wirewound fixed resistors; the two-digit number identifies the

physical size and power rating.

Characteristics: The single-letter symbol identifies the maximum

continuous operating temperature and type of winding as follows:

G (inductive wound) — +250°C maximum continuous operating temperature

N (non-inductive wound)

Resistance: The four-digit number identifies the nominal resistance value,

expressed in ohms; the first three digits represent significant

figures and the last digit specifies the number of zeros to follow.

For values less than 100 ohms, all digits are significant with the letter "R"

representing the decimal point (see the following examples).

Examples:

R050 = 0.05 ohm

R100 = 0.10 ohm

1R00 = 1.0 ohm

10R0 = 10.0 ohms

1000 = 100 ohms

1001 = 1000 ohms

1002 = 10,000 ohms

BHT-ELEC-SPM

3-00-00 Rev. 1 27 MAY 2011 ECCN EAR99

Table 3-7. RER Type Resistance Code

RER65 F 1001 M

Style: The three-letter symbol RER identifies established reliability,

chassis-mounted, power type, wirewound, fixed resistors; the two-digit

number identifies the physical size and power rating.

Resistance tolerance: The single-letter symbol identifies the

resistance tolerance as follows:

F = ±1.0%

Resistance: The four-digit number identifies the nominal resistance

value, expressed in ohms; the first three digits represent significant

figures and the last digit specifies the number of zeros to follow.

For values less than 100 ohms, all digits are significant with the letter

"R" representing the decimal point (see the following examples).

Examples:

R100 = 0.10 ohm

1R00 = 1.0 ohm

10R0 = 10.0 ohms

1000 = 100 ohms

1001 = 1000 ohms

1002 = 10,000 ohms

Failure rate level: The single-letter symbol identifies the life failure

rate as follows:

M = 1.0%/1000 hours

P = 0.1%/1000 hours

R = 0.01%/1000 hours

S = 0.001%/1000 hours

BHT-ELEC-SPM

3-00-00

ECCN EAR99

Table 3-8. RWR Type Resistance Code

RWR74 S 49R9 F M

Style: The three-letter symbol RWR identifies axial-lead, power

type, wirewound, fixed resistors; the two-digit number identifies

the physical size and power rating.

Terminal and winding: Terminal capability and inductive or

noninductive winding designation as follows:

S = Solderable, inductive wound

W = Weldable, inductive wound

N = Solderable, noninductive wound

Z = Weldable, noninductive wound

Resistance: The four-digit number identifies the nominal

resistance value, expressed in ohms; the first three digits

represent significant figures and the last digit specifies the

number of zeros to follow. For values less than 100 ohms, all

digits are significant with the letter "R" representing the decimal

point (see the following examples).

Examples:

R100 to R988 = 0.1 to 0.988 inclusive

1R00 to 9R88 = 1.0 to 9.88 inclusive

10R0 to 98R8 = 10 to 98.8 inclusive

1000 to 9888 = 100 to 988 inclusive

1001 to 9881 = 1000 to 9880 inclusive

1002 to 4022 = 10,000 to 40,200 inclusive

Resistance tolerance: The single-letter symbol identifies the

resistance tolerance as follows:

B = ±0.1%

D = ±0.5%

F = ±1.0%

Failure rate level: The single-letter symbol identifies the failure

rate as follows:

M = 1.0%/1000 hours

P = 0.1%/1000 hours

R = 0.01%/1000 hours

S = 0.001%/1000 hours

27 MAY 2011 Rev. 1 /30

chapter 3 — circuit, component, wire, cable, and harness

Documents