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Illustrated technical information covering Vol 2 Over 800 multi-choice systems questions Study notes and technical information Close up photos of internal and external components A compilation of links to major 737 news stories with a downloadable archive Illustrated history and description of all variants of 737 Detailed tech specs of every series of 737 Databases and reports of all the major 737 accidents & incidents General flightdeck views of each generation of 737's Description & news reports of Advanced Blended Winglets Press reports of orders and deliveries A collection of my favourite photographs that I have taken of or from the 737 Details about 737 production methods A compilation of links to other sites with useful 737 content Get the book of the website A quick concise overview of the pages on this site

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737-200 AIRCRAFT NOTES PART 2.

 

Notes Prepared From B737-200/P&W JT8D MM From 27th October 1994 to 2nd April 1995.

By Mr Meljoe Ferreira

Contents

 

FLIGHT DIRECTOR SYSTEM

AUTOMATIC FLIGHT CONTROL SYSTEM

AUTOPILOT

YAW DAMPER SYSTEM

MACH TRIM SYSTEM

CSD

FIRE DETECTION SYSTEM

ELECTRICAL

 

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FLIGHT DIRECTOR SYSTEM:-

EACH SYSTEM COMPRISES OF:

FLIGHT DIRECTOR INDICATOR,

COURSE DEVIATION INDICATOR,

A ROLL COMPUTER,

A PITCH COMPUTER,

AN INSTRUMENT AMPLIFIER,

CONTROL PANEL

AND

A MODE ANNUNCIATOR.

THE SYSTEM RECEIVES ATTITUDE AND RADIO INFORMATION FROM ASSOCIATED SYSTEMS WHICH ARE DISPLAYED ON THE FLIGHT DIRECTOR INDICATORS.

ROLL AND PITCH CHANNEL COMBINE SOME OF THESE INPUTS AND COMPUTE THE STEERING COMMAND NECESSARY TO MAINTAIN A SELECTED MODE FLIGHT PATTERN.

FD SYSTEM COMPONENTS:-

1. FDI [ADI]:-

PROVIDES SYMBOLIC PICTURE OF AIRCRAFT ROLL AND PITCH ATTITUDE AND FLIGHT DIRECTOR COMMAND DISPLAY.

STEERING COMMANDS ARE DISPLAYED BY V-POINTERS [2 TAPERED BARS],

A TRIANGULAR POINTER ON LEFT SIDE OF FDI DISPLAYS AIRCRAFT DEVIATION FROM GS BEAM

WHILE POINTER REPRESENTING RUNWAY INDICATES DEVIATION FROM VOR/LOC BEAM.

FLAGS:- GYRO,COMPUTER,GS AND RUNWAY FLAGS.

2. CDI [RMI]:-

DISPLAYS MAGNETIC HEADING,RADIO COURSE DEVIATION,TO-FROM THE STN INDICATOR,GS DEVIATION AND

PROVIDES FOR HEADING AND COURSE SELECTION.

FLAGS:-

COMPASS,GS,

VOR/LOC FLAGS.

3.CHANNEL COMPUTERS:-

ROLL AND PITCH CHANNEL COMPUTERS GENERATE ROLL AND PITCH COMMAND SIGNALS TO PROVIDE PILOTS WITH REQUIRED MANUVERES TO FLY A SELECTED FLIGHT PATH WITH OPTIMUM RESPONSE AND MINIMUM OVERSHOOT.

4.FD CONTROL PANEL:-

MODE SELECTION ROTARY SWITCH:-

 FOR SELECTION OF GA, OFF, HDG, VOR/LOC, AUTO APP, MAN GS OR BACKBEAM MODE.

PITCH COMMAND KNOB:- 

PLACES PITCH CHANNEL IN MANUAL PITCH CONTROL PROVIDED GS OR GA MODES ARE NOT SELECTED.

5.APD ANNUNCIATOR.

6.TRANSFER SWITCHES [P5]:-

SELECT ALTERNATE SOURCE FROM VG, COMPASS AND VHF NAV RECEIVERS.

7.INST AMPLIFIER:-

PROVIDES SERVO-AMPLIFIER TO DRIVE CDI AND FDI MOTORS FOR ROLL, PITCH, RADIO ALTIMETER, COMPASS HEADING AND COURSE SELECT.

8.FLT INST ACC UNIT:-

CONTAINS FLAG MONITORING CKT.

SYS TEST:-  

CHK THAT FDI GIVES THE TEST PATTERN, NOSE UP AND 10 DEG ROLL WHENEVER TEST BUTTON IS PRESSED IN ALL MODE SELECTION.

OPERATION:- 

FLIGHT DIRECTOR MODES.

1.OFF MODE:- 

V-BAR IS BIASED OUT OF VIEW AND FDI WORKS AS ARTIFICIAL HORIZON.

2.GA [GO AROUND] MODE:-

SELECT BY EITHER MANUALLY SETTING MODE SELECT SWITCH TO GA OR BY PUSHING EITHER GO-AROUND THRUST LEVER SWITCHES.

AUTO APP,MAN GS OR BACKBEAM SETTING WILL SPRING BACK TO GA IN THIS CASE.FLIGHT DIRECTOR WILL GIVE A 14 DEG PITCH UP,WING LEVEL COMMAND.

3.HEADING MODE:-

ENGAGED WHEN MODE SEL SW IS PUT TO HDG OR MODE SEL SW SET TO VOR/LOC,AUTO APP,MAN GS OR BB PRIOR TO BEAM CAPTURE.[APD-AMBER LT].

HEADING MODE USED TO MANTAIN SELECTED DIRECTION DURING T/O OR PRIOR TO BEAM CAPTURE,ALSO USED TO PERFORM CO-ORDINATED TURNS WHEN CHANGING FROM ONE HEADING TO ANOTHER BY FOLLOWING THE V-BAR COMMAND.

4.MANUAL PITCH COMMAND:-

OFF WHEN EITHER HDG OR BB MODE IS SELECTED. ALLOWS PILOT TO MANTAIN SELECTED PITCH ATTITUDE. CONTROL RANGE -10 TO +15 DEG.

MANUAL PITCH CONTROL OUTPUT INHIBITED WHEN ALT HOLD MODE IS SELECTED.

5.ALTITUDE HOLD MODE:-

ENGAGED WITH MODE SELECTOR:-HDG, VOR/LOC OR BB AND ALT MODE S/W IN 'ON'

POSITION.

6.VOR/LOC MODE:-

MODE SEL IN AUTO APP AND ALT HOLD SW ON.

THE ROLL CHANNEL WILL REMAIN IN HEADING MODE AND PITCH CHANNEL IN ALT HOLD MODE UNTIL VOR/LOC BEAM IS CAPTURED. SUBSEQUENTLY FLT DIRECTOR WILL FOLLOW RADIO COMMAND. VOR/LOC LT ON APD IS AMBER.WHEN VOR/LOC SEL AND GREEN WHEN VOR/LOC BEAM IS CAPTURED.

7.AUTO APP MODE:-

SELECTED AFTER VOR/LOC CAPTURED BY PUTTING SELECTOR S/W TO AUTO APP.AUTO APP LT ON APD TURN AMBER AFTER GS CAPTURE ALT HOLD S/W SPRINGS TO OFF AND GS LT TURNS GREEN.PITCH CHANNEL IS CONTROLLED BY GS BEAM SIGNAL.

8.BACK BEAM MODE:-

ONLY USED TO INTERCEPT LOC BEAM IN REVERSE DIRECTION BY INVERTING BOTH BANK ATTITUDE SIGNAL AND COMMAND OUTPUT TO V-BAR.

FDI = ADI [ATTITUDE DIRECTION INDICATION]

CDI = HSI [HORIZONTAL SITUATION INDICATOR]

TROUBLESHOOTING:-

1.FDI COMPUTER FLAG IN VIEW AND V-BARS OUT OF VIEW:-

INTERCHANGE OR REPLACE PITCH COMPUTER,ROLL COMPUTER,

FDI.

2.FDI COMPUTER FLAG IN VIEW AND V-BARS ALSO IN VIEW:-

INTERCHANGE FDI,

REPLACE FAULTY FDI.

3.FDI V-BARS DO NOT ROTATE IN ROLL OR DO NOT FOLLOW HDG CONTROL KNOB PROPERLY:-

FDI,ROLL COMPUTER,

CDI.

4.V-BARS DO NOT MOVE IN PITCH OR DO NOT FOLLOW PITCH CONTROL KNOB:-

CDI

PITCH COMPUTER

F/D CONTROL PANEL.

5.SYSTEM DOES NOT TRACK OR CAPTURE LOC SIGNAL IN VOR/LOC,AUTO APP OR BB MODES:-

ROLL COMPUTER, CDI,

F/D CONTROL PANEL.

6.SYSTEM DOES NOT TRACK OR CAPTURE GS SIGNAL:-

PITCH COMPUTER,

F/D CONTROL PANEL.

7.SYSTEM DOES NOT HOLD ALT, OR DOES NOT TRACK ALT CHANGE WHWN IN ALT HOLD MODE:-

PITCH COMPUTER,F/D CONTROL PANEL,

FLT INST ACC UNIT.

8.FDI V-BAR DO NOT SHOW PITCH UP COMMAND WHEN GA MODE SELECTED:-

F/D PITCH COMPUTER,F/D CONTROL PANEL.

9.F/D PROGRESS DISPLAY ANNUNCIATOR [APD] MODE LT DOES NOT COME ON WHEN MODE SELECTED:-

LT, BULB,F/D PITCH OR ROLL COMPUTER,F/D MODE SELECT ORT PANEL,

APD.[FOR GS OR GA, INTERCHANGE PITCH COMPUTER, FOR ALL OTHER MODES, REPLACE ROLL COMPUTER].

10.VOR/LOC AND GS FLAGS ON FDI AND CDI:-

MOVE VHF NAV S/W TO ALTERNATOR POSITION AND CHK FLAGS DISAPPEAR, IF NOT, IT IS A F/D SYSTEM TROUBLE. CHK ELECTRONIC MASTER SW ON. RERACK FLT INST ACC UNIT.

11.GYRO FLAG ON FDI-1:-

MOVE VG TX SW TO VG ON AUX.CHK IF FLAG DISAPPEARS [THEN, IT IS A VG PROBLEM]. IF NOT, THEN REPLACE/RERACK FD PITCH COMPUTER, FLT INST ACC UNIT AND

F/D CONTROL PANEL.

12.COMPASS FLAG ON CDI-1,COMPUTER FLAG ON FDI:-

MOVE COMPASS TRANSFER SW TO BOTH ON 2.IF FLAG DISAPPEARS, IT IS A DG PROBLEM.IF NOT RERACK FLT INST ACC UNIT,ROLL AND PITCH COMPUTER.

13.GYRO FLAG OF FDI:-

TRANSFER GYRO BY SW IN P5.IF FLAG STILL PERSISTS RERACK/INTERCHANGE F/D ACC UNIT.

14.FLIGHT DIRECTOR/COMPASS SYSTEM FLAGS:-

COMPUTER FLAG ON FD,COMMAND BARS OUT OF VIEW:-

POWER FAILURE

COMPASS FAILURE

15.COMPASS FLAG ON CM1,RMI,CM2,CDI,COMPUTER FLAG ON FDI:-

COMPASS SYSTEM 1 FAILURE, CLEAN PLUG, EXERCISE TRANSFER S/W TX COMPASS SYSTEM TO BOTH ON 2.

16.RUNWAY FLAG ON FD AFTER LOC TUNED IN:-

LOC FAILURE OR BELOW 200FT RA FAILURE.

17.RUNWAY VOR/LOC AND COMPUTER FLAG:-

LOC SIGNAL FAILURE.

18.FD G/S, CDI G/S, FD COMPUTER FLAG:-

G/S SIGNAL FAILURE.

19.ALTIMETER FLAG, ALT ALERT FLAG, GPWS, MACH TRIM TEST FAILURE, PRESSURISATION SYSTEM [AUTO MODE] SNAG :-

AIR DATA COMPUTER.

20.RADIO ALTIMETER FLAG:-

IF P1 SIDE FAULTY, INTERCHANGE WITH P2 SIDE EXERCISE CB FOR 4-5 TIMES, RERACK RADIO ALTIMETER MODULE [E3-4].

NOTE :- GPWS INOP IF SNAG IN RADIO ALTIMETER MODULE.

21.FORCE TRANSDUCER [ROLL AND PITCH]:-

PROVIDES CONTROL WHEEL STEERING SIGNAL TO AUTOPILOT WHEN IT IS ENGAGED.

22.FLAP POSITION SWITCHES:-

2 FLAP POSITION SW ARE USED IN A/P CONTROL SYSTEM. WHEN FLAPS NOT UP, FLAPS UP SW WILL ENABLE THE STAB TRIM SERVO MOTOR TO CHANGE FROM LOW SPEED TO HIGH SPEED.

23.A/P SOLENOID VALVE:-

WHENEVER A/P IS ENGAGED, OPENING THE VALVE.HYD PR IS PORTED THRU THE VALVE TO ENGAGE MECHANISM AND SELECTOR VALVE.

24.TRANSFER VALVE:-

AUTOPILOT COMMAND SIGNALS ARE APPLIED TO THE TRANSFER VALVE, WHICH CAUSES A JET PIPE TO DEFLECT DEVELOPING DIFF PR ACROSS A VALVE WHICH FURTHER DIRECT HYD PR TO THE PCU TO THE PCU ACTUATOR.

25.POSITION OR LINEAR TRANSDUCER:-

SUPPLIES A FEEDBACK SIGNAL TO A/P CONTROL SYSTEM WHEN THE ACTUATOR MOVES.

NOTE:- WHENEVER RERACKING ANY MODULE, REMOVE POWER FROM THE SYSTEM FOR A FEW MTS [3-4] BEFORE PROCEEDING WITH RERACKING/REPLACEMENT

Contents


AUTOMATIC FLIGHT CONTROL SYSTEM

1.YAW DAMPER SYSTEM.2.AUTOPILOT PITCH CHANNEL.3.AUTOPILOT ROLL CHANNEL.

4.MACH TRIM SYSTEM.

Contents


AUTOPILOT

1.PITCH CHANNEL.

2.ROLL CHANNEL.

PITCH CHANNEL ENGAGEMENT LOGIC:-

ELEX-1 ENERGISED.

BATTERY BUS ENERGISED.

ADC AIRSPEED SIGNAL GOOD.

30V DC MONITOR GOOD.

CORRECT PITCH CALIBRATION INSTALLED.

CWS NOT OUT OF DETENT.

NO HOT SHORT STAB TRIM SIGNAL.

FLAPS SYNCHRONIZED.

A/P STAB TRIM CUTOUT SWITCH - NORMAL.

MAIN ELECTRIC STAB TRIM MOTOR NOT ENGAGED.

VG FLAG OUT OF VIEW.

VG TRANSFER RELAY GOOD.

A/P CONTROL PANEL GOOD.

A/P ACC. BOX GOOD.

FLT CNTRL B SYSTEM ON.

CONTROL WHEEL DISENGAGE SW NOT OPEN.

ROLL CHANNEL ENGAGEMENT LOGIC:-

ELEX-1 ENERGISED.

BATTERY BUS ENERGISED [NOT ON STANDBY].

ADC AIRSPEED SIGNAL GOOD.

30V DC MONITOR GOOD.

CORRECT ROLL CALIBRATOR INSTALLED.

CWS NOT OUT OF DETENT.

AILERON FORCE LIMITER CLUTCH ENGAGED.

VG FLAG OUT OF VIEW.

DG FLAG OUT OF VIEW.

VG & DG TRANSFER RELAYS GOOD.

A/P CONTROL PANEL GOOD.

A/P ACC BOX GOOD.

FLT CNTRL 'B' SW ON.

CONTROL WHEEL A/P DISENGAGE S/W NOT OPEN.

CAUTION:- DO NOT REMOVE PITCH OR ROLL CHANNELS FOR AT LEAST 3 MINUTES AFTER REMOVING POWER FROM THE SYSTEM, RATE GYRO MAY BE DAMAGED IF COUPLER IS MOVED BEFORE GYRO IS ALLOWED TO SPIN DOWN.

INTERLOCKS:-

FOLLOWING IS A LIST OF INTERLOCKS REQUIRED TO KEEP EACH MODE SELECT S/W COIL ENERGISED.

I.NAV MODE SELECT S/W:-

POSITION INTERLOCKS

1. MANUAL NONE

2. VOR/LOC ROLL ENGAGE

VOR/LOC SELECTEDNO ILS/VOR CNTRL PANEL TEST

NO NAV TRANSFER

3. AUTO APP OR MAN G/S ROLL ENGAGE

PITCH ENGAGEAUTO APP MAN GS SELECTED TURB NOT SELECTEDILS FLAG SELECTEDADC ALTITUDE GOODNO VOR/ILS CONTROL PANEL TEST

NO NAV TRANSFER

II.HEADING MODE SELECT S/W:-

1. CENTERED NONE2. HDG SEL ROLL ENGAGEDHDG SEL SELECTEDVOR/LOC NOT SELECTEDROLL CWS NOT OUT OF DETENT

 

PITCH CHANNEL SIGNAL BLOCK DIAGRAM:-

INPUTS OUTPUTS

 

CWS TRANSDUCER -------> ³ ³-----> ELEVATOR PCU

ALTITUDE REF SYS -----> ³ ³ <--------Ù

C.A.D.C. -------------> ³ ³-----> A/P STAB SERVO MOTOR

VHF NAV SYS-----------> ³ ³ <--------Ù

LOW RANGE RADIO ALT---> ³ ³

AUTOPILOT CNTRL PANEL-> ³ ³----->AUTO PILOT WX LT

A/P DISENGAGE SW------> ³ ³

³ ³----->STAB OUT OF TRIM [P2]

 

PITCH CNTRL CHANNEL

E-1NOTE:- MOST OF THE AUTOPILOT SNAGS CAN BE RECTIFIED BY RERACKING/REPLACEMENT OF A/P ROLL AND PITCH CHANNEL,A/P ACC BOX,A/P CONTROL PANEL.

 

A/P MAY BE INOPERATIVE UNDER M.E.L.

STAB OUT OF TRIM LT, MAY BE U/S IF A/P NOT USED.

AUTOPILOT TROUBLESHOOTING:-

1.PITCH CHANNEL DOES NOT ENGAGE [ADC, VG, A/P CUTOUT S/W, MAIN ELECTRIC STAB AND POWER OK]:-

PITCH CHANNELA/P ACC BOXA/P CONTROL PANELFLAP UP LIMIT SWITCHMT FLAP S/W OR A/P STAB TRIM SERVO

PITCH CWS FORCE TRANSDUCER

2.PITCH CHANNEL INOP:-

PITCH CHANNELA/P ACC BOXA/P CONTROL PANEL3.PITCH CHANNEL DOES NOT RESPOND TO CWS INPUTS:-PITCH CHANNELCADC

CW FORCE TRANSDUCER

4.A/P DOES NOT CAPTURE GLIDE SLOPE WHEN ON APPROACH:-

PITCH CHANNEL

NAV RADAR

5.ROLL CHANNEL DOES NOT ENGAGE[ADC,VG,DG AND PWR OK]:-

ROLL CHANNELAILERON FORCE LIMITERA/P ACC BOXA/P CONTROL PANEL

ROLL CWS FORCE TRANSDUCER

5A.A/P ENGAGE S/W NOT LIFTING FROM DISENGAGED POSITION:-

CHK CBRECYCLE STAB TRIMCUTOUT SWITCHESCHK SYSTEM SELECTION ON HYD SYS B [A/P CONTROL PANEL]

FAULTY FORCE TRANSDUCER

6.AILERON KICK SHARPLY ON ENGAGEMENT:-

ROLL CHANNEL

A/P ACC BOX

7.ROLL CHANNEL INOP:-

ROLL CHANNELA/P ACC BOX

A/P CONTROL MODULE

8.ROLL CHANNEL DOES NOT RESPOND TO CWS INPUTS:-

ROLL CHANNEL.

9.AIRCRAFT DOES NOT RETURN TO WINGS LEVEL WHEN BACK ANGLE < 5ø AND IN HDG HOLD MODE:-

ROLL CHANNEL.

10.A/P DOES NOT CAPTURE VOR RADIAL OR LOC BEAM:-

ROLL CHANNELNAV RECEVIER

 

AUTOPILOT MODE SELECT TROUBLESHOOTING:-

11.NAV MODE SWITCH DOES NOT REMAIN IN VOR/LOC,AUTO APP OR MAN G/S.:-

A/P ACC BOXROLL CHANNEL

A/P CONTROL PANEL

12.NAV MODE SW DOES NOT REMAIN IN VOR/LOC ONLY [AUTO APP,MAN G/S OK]:-

ROLL CHANNEL

13.NAV MODE SW DOES NOT REMAIN IN AUTO APP AND MAN GS[VOR/LOC OK]:-

ROLL OR PITCH CHANNEL

AUTOPILOT HYDRAULIC POWERPACK TROUBLESHOOTING:-

14.ROLL OR PITCH CHANNEL INOP:-

ROLL OR PITCH CHANNEL

SOLENOID VALVE [AIL OR ELEV PCU]

15.ROLL OR PITCH CHANNEL INTERMITTENT:-

A/P ACC BOX

A/P CNTRL PANEL

16.AILERONS OR ELEVATORS MOVES TO LIMITS ON ENGAGEMENT [ROLL OR PITCH CHANNEL KNOWN OK]:-

POSN TRANSDUCERS

TRANSFER VALVE [ON 'B' PCU]

17.STAB OUT OF TRIM LT COMES ON WITH A/P SELECTED OR EXCESSIVE CWS FORCE IN PITCH WITH A/P SELECTED:-

PITCH CHANNELA/P ACC UNIT

ELEV FORCE TRANSDUCER

FAILURES WHICH OCCUR DUE TO FAULTY OUTPUTS FROM THE GYROS, NAVIGATION RECIEVER, AIR DATA COMPUTER OR RADIO ALTIMETER WILL USUALLY SHOW UP AS FLAG INDICATOR OR ON BLACK BOX DUE TO SELF MONITORING CKTS AND ASSOCIATED FLAG VOLTAGES WITH THE COMPONENTS.

PROBLEMS DUE TO SIGNALS FROM ASSOCIATED SYSTEM ARE DEALT WITH IN NAVIGATION CHAPTER.

TEST ROLL ENGAGE INTERLOCKS:-

1.A/P SELECT SWITCH IN 'B' POSN.

2.WITH CNTRL WHEEL AND COLUMN IN DETENT,ENGAGE AIL ENGAGE SW ON A/P PANEL.

3.DEPRESS A/P DISENGAGE BUTTON ON CAPTS OR F/OS CONTROL WHEEL,CHK AIL CHANNEL DISENGAGES WITH A/P DISENGAGE WX LT ON MOMENTARLY.

4.ENGAGE AIL CHANNEL,OPEN A/P ENGAGE INTERLOCK CB.OBSERVE A/P AIL CHANNEL DISENGAGES + A/P WX LT ILLUMINATES AND FLASHES.

5.DEPRESS CAPTS WX LT ON LH INST PANEL,OBS WX LT EXTINGUISH AND AIL ENGAGE SW CANNOT BE ENGAGED.

6.CLOSE A/P ENGAGE INTERLOCK CB,ENGAGE AIL CHANNEL SW.

7.REPEAT STEPS 4 TO 6 WITH ROLL CHANNEL AC & DC,DERIVED RATE AC CB ON P6,COMPASS #1 VG AND ADC-1,115VAC CB ON P18 LOAD CONTROL CENTER.

8.ENGAGE AIL CHANNEL,OPEN COMPASS #2 CB,[P6] AND AUX VG [P18] CB.OBS AIL CHANNEL DOES NOT TRIP,CLOSE CBS.

9.PLACE VG SELECT SW IN CAPT ON AUX POSN OBS AIL ENGAGE SEW DISENGAGE + WX LT FLASHES.

10.ENGAGWE AIL CHANNEL,PLACE COMPASS SW TO BOTH ON COMP-2.OBS AIL CHANNEL TRIPS.

11.WITH CONTROL WHEEL OUT OF DETENT,TRY TO ENGAGE AIL CHANNEL,IT WIL NOT ENGAGE.

12.WITH AIL CHANNEL ENGAGED MOVE STBY PWR SW TO OFF POSN,A/P CHANNEL WILL TRIP.

13.POSN FLT CONTROL A SW TO OFF,ENGAGE AIL CHANNEL,MOVE CONTROL WHEEL AND OBS AILERON RESPOND TO CONTROL WHEEL STEERING.

Contents


YAW DAMPER SYSTEM

YD SYSTEM MAY BE INOP:- POSN YD SW TO OFF + RESTRICTS A/P OPN TO 30,000 FT OR BELOW.

YD SYSTEM CONTROLS THE RUDDER TO DAMPEN OUT OSCILLATIONS ABOUT YAW AXIS WITHOUT AFFECTING THE TURNING OF THE AIRCRAFT.

YD SYSTEM COMPONENTS AND LOCATIONS:-

1.Y/D ON/OFF SW + YD AMBER LT --> P5.2.YD TEST SW + INDICATOR ---> P-2.3.YD COUPLER ---> E1-2.4.A/P ACC UNIT ---> E1-3.5.RUDDER PCU ---> VERTICAL STABLIZER.

³ON/OFF S/W ³------------>³A/P ³

³FAIL LT ³<------------³ACC ³

<-----³UNIT ³

 

³ E1-3

³TEST S/W ³----->³YAW ³------------>³Rÿ ³

³INDICATOR ³<-----³DAMPER ³ ³U P ³

COUPLER³ ³D C ³

P2 ----->RUDDER.

E1-1 ³E ³

Ú-------->³R ³

HYD SYS ÀÄÄÄÄÄÙ

'B' PR

SYSTEM TEST:-

ELECT PWR + SYSTEM 'B' POWER AVAILABLE Y/D S/W ON. MOVE TEST SW TO LEFT. THE CENTER BAR ON INDICATOR MOVES TO LEFT AND FINALLY TO CENTER. MOVE TEST S/W TO RIGHT, INDICATOR MOVES RIGHT TO CENTER.

RATE GYROY/D COUPLER

> Y/D COUPLER

OPERATION:- Y/D RATE GYRO [COMPLEX] IS THE SENSING ELEMENT, WHICH PROVIDES AC OUTPUT WHOSE PHASE REPRESENTS DIRECTION AND AMPLITUDE REPRESENTS RATE OF MOVEMENT.

THE SIGNAL PASSES THRU AN AIRSPEED POTENTIOMETER IN CADC WHICH REDUCES SIGNAL AS AIRSPEED INCREASES.

THE SIGNAL IS THEN AMPLIFIED BY VALVE AMPLIFIER IN Y/D COUPLER AND APPLIED TO TRANSFER VALVE OF SYS 'B' RUDDER PCU. HYD PR MOVES Y/D PISTON WHICH MOVES THE CONTROL VALVE [THUS MOVING THE MAIN ACTUATOR + RUDDER], LVDT PROVIDES FEEDBACK TO Y/D COUPLER.

YAW DAMPER MOVEMENT OF RUDDER:-

SELF TEST COUPLER:- 

NEEDLE SHOULD BE IN RED P/N 2583880 [SELF TEST 1,2,3,4 FAILS. IF TEST 5 FAILS, EITHER COUPLER OR SOLENOID VALVE FAULTY].

TROUBLESHOOTING:-

1.Y/D SYSTEM FAILS COCKPIT TEST:-

COUPLER FAULTY

SOLENOID VALVE ON PCU FAULTY

2.Y/D INDICATOR BAR AND RUDDER LOCK IN EXTREME POSITION WITH YAW DAMPER ENGAGED:-

COUPLERTRANSFER VALVE

3.RUDDER LOCKED IN EXTREME POSITION WITH INDICATOR BAR CENTERED, Y/D ENGAGED:-

COUPLERPOSITION TRANSDUCER

4.Y/D INDICATOR BAR DOES NOT MOVE WHEN SYSTEM TESTED, RUDDER MOVES OK:-

INDICATOR

5.RUDDER OSCILLATES OR AIRCRAFT DUTCH ROLLS WITH Y/D ENGAGED:-

COUPLER

RUDDER HYD SYS FAULT

6.Y/D SYSTEM OPTS INTERMITTENTLY:-

A/P ACC UNIT

7.HIGH RUDDER PEDAL FORCES OR RUDDER PEDAL KICKS BACK OR ERRATIC RUDDER PEDAL STEERING ON GRD:-

BINDING WITHIN STANDBY RUDDER ACTUATOR. [HYD PWR 'OFF', DISCONNECT INPUT ROD FROM STANDBY ACTUATOR INPUT LEVER .MOVE INPUT LEVER, FORCE SHOULD NOT BE MORE THAN 1 lb.

Contents


MACH TRIM SYSTEM

MT SYSTEM MAY BE INOP IF AIRCRAFT SPEED DOES NOT EXCEED 0.74 MACH.MT SYSTEM PROVIDES AUTOMATIC DISPLACEMENT OF ELEVATORS AS A FUNCTION OF MACH NO IN THE MACH TUCK [NOSE DOWN] REASON.1.TEST S/W AND FAIL LT --->P52.MACH TRIM COUPLER---->E1-23.MACH TRIM ACTUATOR--->TAIL CONE AREA

4.MT FLAP S/W ---> FLAP CONTROL UNIT

SYSTEM TEST:-

WITH BOTH ELECTRICAL PWR AND HYD SYS B PR, AVAILABLE, PRESS MACH TRIM TEST BUTTON [FLAP IN FULL UP POSITION].

1.CONTROL STICK MOVES AFT.

2.MT FAIL LT COMES ON.

ON RELEASE OF MT TEST S/W CONTROL STICK RETURNS TO NEUTRAL POSITION + MT FAIL LT GOES OFF.

NOTE:- FAIL LT WILL NOT COME ON IF FLAPS ARE NOT UP.

OPERATION:- MACH INFORMATION,RECIEVED FROM ADC IS USED BY MT COUPLER TO GENERATOR A MACH TRIM SERVO POSITION COMMAND SIGNAL WHICH IS ROUTED TO MT ACTUATOR [SIGNAL MODIFIED/CANCELLED IF FLAP NOT FULL UP].THE ACTUATOR CHANGES ELEVATOR POSITION THRU ELEVATOR FEEL AND CENTERING UNIT AND ELEVATOR PCU IN ORDER TO MANTAIN CORRECT PITCH ATTITUDE.

TROUBLESHOOTING:-

1.SYS FAILS COCKPIT TEST:-

MT COUPLER [PRESS TEST S/W FOR 15 SEC,IF NO LT CHANGE COUPLER,IF LT ILLUMINATES AND DOES NOT GO OFF CHANGE TEST S/W].

TEST S/W

2.MT FAIL LT,COMES ON WITH FLAPS DOWN:-

MT FLAP S/W [ADJUST]MT COUPLER

Contents

 


CSD

CSD + GEN MAY BE U/S PROVIDED APU GEN OK + APU FUEL HEATER OK.[MAINT APU

BLEED LOAD + ELECT LOAD ALTITUDE LIMITS].

REASON FOR CSD REMOVAL:-

1.LOW OIL PRESSURE.AMBER LT 120 TO 160 PSI RANGE.2.HIGH OIL TEMP.AMBER LT > 157øC.3.METAL IN THE CHIP DETECTORS.4.CSD FILTER POP OUT BUTTON POPS OUT.5.OIL DISCOLOURATION.6.FLUCTUATING FREQUENCY AND LOAD SNAG.

7.REPEATED OIL SERVICING > 5 TIMES BETWEEN CHK C INSPECTION`

LOP LT COMES ON WHEN PR DROPS TO 120-160 PSI.NORMAL PRESSURE DEVELOPED BY CHARGE PUMP IS 200 PSI.

HOT LT COMES ON WHEN OIL TEMP ò 157øC.

NORMAL "OIL IN" TEMP = 55øC [APPROX].

NORMAL "RISE" TEMP = 10øC [APPROX].

IF OIL "IN TEMP" HIGH CHK CSD OIL COOLER.

IF LOP LT FLICKERS IN FLT AND CSD DE-ACTIVATED THEN :-

1.RESET CSD DISCONNECT HANDLE.

2.CLEAN OIL PRESSURE PLUG.

3.REMOVE CSD PANEL AND CLEAN PLUG.

4.OPERATE ENGINE AND CHECK IF OIL PRESSURE LT COMES ON OR FLICKERS.IF SO, REPLACE CSD.

NOTE:- WHENEVER CSD REPLACED, IN-LINE CSD FILTER SHOULD BE REMOVED, PLACED IN A BAG AND ATTACHED TO CSD.

NO OF ELECTRICAL CONNECTION ON CSD:-

1.CHARGE PR SENSOR FOR LOP LT.2.DISCONNECT SOLENOID.3.OIL TEMP OUT [TO OIL COOLER].4.OIL TEMP IN [FROM OIL COOLER].

5.157øC THERMOSTAT [FOR HOT LT].

 

NORMAL OIL CAPACITY IN CSD = 1¬ US GALLONS.

CAUTION:- OVERFILLING MAY CAUSE OVERHEATING.

IF CSD DEACTIVIATED IN FLT:-

IT CAN ONLY BE RESET AFTER LANDING LANDING BY PULLING THE RESET HANDLE ON CSD WITH ENGINE NOT ROTATING.

CSD HAS A GOVERNOR ADJUSTMENT FOR ADJUSTING FREQUENCY IN THE AIRCRAFT [CLOCKWISE TO INCREASE FREQUENCY,1 TURN = 2 HZ].

CSD OIL COOLER:-

HAS BOTH THERMAL AND PR DIFFERENTIAL BYPASS.THERMAL BYPASS:-FULL OPEN BELOW 150øF.FULL CLOSED AT OR ABOVE 170øF.

PR DIFF BYPASS CRACKS OPEN AT 50 PSID AND IS FULLY OPEN AT 90 PSID.

RESIDUAL VOLTAGE OF GEN :- 15-20 VOLTS [CHK WITH ENGINE ROTATING].

TO DISCONNECT CSD N2 MUST BE ROTATING AT 20% RPM.

LOP LT COMES ON,IT MAY BE DUE :-

1.DEFECTIVE CSD PANEL [THERE IS A SENSE CARD FOR LOP IN THE PANEL].

2.DEFECTIVE PR SENSOR, CHANGE CSD.

3.DEFECTIVE CHARGE PUMP, CHANGE CSD.

CAUTION:-

BEFORE RECONNECTING A DISCONNECTED CSD TO PERFORM TROUBLE SHOOTING, CHK CSD OIL FILTER PRESSURE DIFFERENTIAL INDICATOR, CHK CSD OIL LEVEL AND CONDITION ,AND CSD MAGNETIC CHIP DETECTORS.

RECONNECTING CSD WITH FAULTS IN THESE AREAS MAY RESULT IN SEVERE DAMAGE TO CSD.

CSD INSPECTION/CHECKS:-

INTERNAL WEAR OF CSD IS DETERMINED BY OBSERVING MAGNETIC CHIP DETECTOR.

1A.REMOVE MCD BY REMOVING ONLY INNER PLUG WITH 9/16 INCH HEX.DO NOT REMOVE DRAIN PLUG.

B.CHK MATERIAL COLLECTED BY MCD.

C.SMALL AMOUNT OF MATERIAL FUZZ IS NORMAL.

D.HEAVY DEPOSITS INDICATE EXCESSIVE WEAR, CLEAN AND REPLACE MCD.RECHECK AFTER ENGINE RUN,IF HEAVY DEPOSITS FOUND, REPLACE CSD, CSD COOLER AND ASSOCIATED TUBINGS.

E.BRIGHT METAL DEPOSITS OF CHIPS OR FLAKES, REPLACE CSD, CSD COOLER AND ASSOCIATED TUBINGS.

INSTALL MCD TORQUE 15-20 lbin.

2.CHK OIL LEVEL AT SIGHT GAGE.

3.CHK LINE OIL FILTER PR DIFFERENTIAL INDICATOR,CHANGE CSD IF OIL PR DIFFERENTIAL INDICATOR HAS POPPED OUT.

4.EXAMINE OIL FOR DISCOLOURATION DUE TO CONTAMINATION,COKING,EXCESSIVE TEMPERATURE,REPLACE CSD AND FLUSH OIL COOLER.

CHECK CSD AND GENERATOR OPERATION AFTER CSD CHANGE WITH EENGINE OPERATING:-

1.START ENGINE AND RUN AT IDLE.

2.CLOSE GCR BY MOMENTARILY MOVING GEN S/W TO ON.VOLTAGE READING 115V AND FREQUENCY 400ñ1 HZ.IF NOT SHUTDOWN ENGINE.[FREQ CAN BE ADJUSTED].

3.CHK NEWLY INSTALLED GEN OUTPUT VOLTAGE AND FOR PHASE REVERSAL.

4.SHUTDOWN ENGINE AND CHK OIL LEVEL.

5.CHK CSD FOR OIL LEAKS.

TROUBLESHOOTING:-

CAUTION:-

BEFORE RECONNECTING A DISCONNECTED CSD TO PERFORM TROUBLESHOOTING CSD TO PERFORM TROUBLESHOOTING, CHK CSD OIL FILTER, PR DIFFERENTIAL INDICATORS. CSD OIL LEVEL AND CONDITION AND CSD MAGNETIC CHIP DETECTOR.

 

CSD LOP LT REMAINS 'ON' AFTER STARTING ENGINE:-

STARTING ENGINE.MOVE GEN S/W TO ON ----------------Â-----------------------------------ÂCHK VOLTAGE ³ ³³ UNSTABLE VOLTAGE VOLTAGE +FRE-NO VOLTAGE,CHK RESIDUAL + FREQUENCY QUENCY OK.VOLTAGE. -------------------------³ ³³ ³ CHK OIL PR³ NO RESIDUAL VOLTAGE SENSORRESIDUAL VOLTAGE OK, INPUT SHAFT SHEARED, ³THEN CHK CSD RESET HANDLE REPLACE CSD. CHK CSD³ PANEL ONIF CONNECTED CHK ------------------- P5.OIL LEVEL. ³³ OIL OKOIL LEVEL LOW CHK OIL PR SCREENS³ ³ CHK CSD OIL FILTER Â----Á-------ÂAND MCD. IF DEFECTIVE IF NOT,CHK CSD PANEL ON P5,REPLACEREPLACE IT IF DEFECTIVEÂ--------------------------------³ ³NORMAL,FILL CSD EXCESSIVE,REPLACE CSD,WITH OIL,OPT SYS & CHK COOLER,FILTER AND TUBING.

FOR OIL LEAKS.

 

CSD OIL TEMPERATURE RISE ò 20øC:-

³

STOP ENGINE CHK FOR

CORRECT OIL LEVEL

IF LOW CHK CSD OIL IF OK,CHK OIL DISTRIBUTION SYSTEM FILTER,MCD FOR CONDITION. FOR CLOGGING, COOLER, LINES, FILTER

³ ETC. ³

³ CHK OIL COOLER FOR IF CLOGGED CLEAN

³ BLOCKED AIR PASSAGE AND RECHK AFTER

³ ENGINE GRD RUN.

³ EXCESSIVE,REPLACE CSD,

NORMAL,FILL CSD TO COOLER,FILTER & LINES.

CORRECT LEVEL AND CHK FOR OIL LEAKS.

TRANSMISSION CASE IF LEAKS FROM EXTERNAL PARTS LIKE COOLER,

INPUT & OUTPUT FILTER, TUBING ETC, THEN REPLACE DEFECTIVE LEAKS, REPLACE CSD. PARTS.

 

CSD OIL TEMPERATURE GAUGE INDICATES FULL SCALE:-

STOP ENGINE

CHK RESISTANCE OF EACH

SENSOR [97-100ê]

IF OK, REPLACE THE IF NOT OK, REPLACE THE TEMPERATURE INDICATOR. SENSOR.

Contents

 


FIRE DETECTION SYSTEM

1.ENGINE DETECTION/EXT SYSTEM [FIRE/OVHT] 2.APU FIRE DETECTION/EXTINGUISHING SYSTEM.3.WING BODY OVHT DETECTION SYSTEM.4.WHEEL WELL FIRE DETECTION SYSTEM.5.CARGO SMOKE DETECTION SYSTEM.

6.LAVATORY FIRE EXTINGUISHING SYSTEM.

WHEEL WELL FIRE DETECTION SYSTEM MAY BE INOPERATIVE IF BRAKES ARE CHECKED JUST BEFORE ENGINE START UP [NOT HOT] + L/G KEPT DOWN AFTER T/O FOR 10 MTS FOR BRAKE COOLING.

RH WING BODY OVHT DETECTION SYSTEM MAY BE U/S IF LH PACK AND LH ENGINE USED FOR AIRCRAFT PRESSURISATION.

LH WING BODY OVHT DETECTION SYSTEM MAY BE U/S IF RH PACK AND RH ENGINE USED FOR AIRCRAFT PRESSURISATION AND APU USED ONLY FOR ENGINE START.

OVHT = 400øC

FIRE = 600øC

 

FIRE TEST:-

DURING TEST,IF ANY OF P8 AMBER LTS REMAINS OFF,THAT MEANS THERE IS EITHER OPEN OR SHORT CKT.

TO CHK FOR OPEN/SHORT CKT,OPEN E&E COMPT AND CHK FOR LTS ON ENGINE & APU FIRE DETECTION ACC.MODULE [E3-3 RACK].IF RESPECTIVE ENGINE OVHT/FIRE LT IS ON MEANS A SHORT CKT.

IF ALL LTS ARE OFF,THEN PRESS TEST SWITCH ON THE MODULE.IF ALL OTHER LTS EXCEPT THE CONCERNED LT COMES ON THERE IS AN OPEN CKT.

 

APU FIRE BOTTLE DISCHARGE INDICATOR:-

RED:- THERMAL DISCHARGE AT 266øF.

YELLOW:- NORMAL DISCHARGE DUE ACTUATION OF APU FIRE HANDLE.

APU DISCHARGED LT ON P8 COMES ON AT 250 PSI.DISCHARGE DISC MAY BE MISSING PROVIDED APU FIRE BOTTLE PRESSURE CHECKED OK + DISCHARGE LT ON P8 OFF.

WING BODY OVHT:-IF LT COMES ON PUT APU/ENGINE BLEED OFF. IF THE WARNING GOES OFF, GENUNINE WARNING [BLEED AIR LEAKAGE CAUSING OVHT].

LH WING BODY OVHT:-ENG STRUT,LH L/E,LH AIR COND BAY,FWD KEEL BEAM,AFT CARGO,SECTION 46 & 48[APU BLEED].

FOR TESTING WING BODY OVHT,PRESS TEST SWITCH ON P5 AIR COND PANEL,BOTH WING BODY OVHT LTS + AIR COND ANNUNCIATOR LT ON P7 COMES ON.THIS CHKS CIRCUIT CONTINUITY.

IF THERE IS ANY SHORTING WING BODY OVHT WILL REMAIN ON,OVHT LT WILL REMAIN ON OVHT LT ON THE OVHT MODULE IN E&E COMPT [E3-2] WILL ALSO COME ON.

TO ISOLATE THE FAULT,START TESTING WITH SWITCH 1,2&3.UP POSN IS GRD FAULT.IN THIS POSITION IF THE LT GOES OFF THE CKT BEING TESTED IS OK.IF OVHT LT ON MEANS CKT IS SHORT CKT.

IN CASE OF OPEN CKT,START WITH SW 1,2&3,DOWN POSITION OF SWITCH IS FOR TESTING CONTINUITY.

IN THIS POSITION,THE OVHT LT SHOULD COME ON [CONTINUITY OK]. IF THE LT REMAINS OFF THERE IS AN OPEN CKT.

S/W 1,2&3 USED FOR ISOLATING FAULT IN LH OVHT CKT ONLY.

RH WING BODY OVHT:-RH ENGINE STRUT, RH WING L/E, RH AIR COND BAY.

FOR RH WING BODY OVHT CHK THE SENSOR PHYSICALLY.

 

EITHER LH OR RH WING BODY OVHT CAN BE U/S UNDER M.E.L. PROVIDED ITS OPEN CKT OR GROUNDED [SHORTED] ie THERE IS A FAULT IN DETECTION SYSTEM AND NOT A GENUINE OVHT SNAG.

SQUIB TEST:-

FOR FIRE EXTINGUISHING SYSTEM CHK THE CONTINUITY FROM FIRE HANDLE TO THE FIRE EXTINGUISHING BOTTLE SQUIB [FIRING SURFACE].IF BOTTLE DISCHARGED SQUIB TEST WILL NOT COME ON.

FAILURE OF ANY OF THE 3 GREEN LTS TO COME 'ON' DURING SQUIB TEST:-

CHK THE LT BULBS [IF FOUND FUSED REPLACEIT]. CLEAN THE PLUG ON THE FIRE EXTINGUISHING BOTTLE AND PLUG UNDER THE FIRE MODULE ON P8 PANEL WITH CONTACT CLEANER. IF THE FAULT DETECTED IN INDICATOR LT CKT,AIRCRAFT CAN BE RELEASED UNDER M.E.L. IF NOT, GROUND THE AIRCRAFT AT OUTSTATION, AS SQUIB TEST FAILURE INDICATES EXTINGUISHING SYSTEM U/S.

E3-3 RACK FIRE ACC MODULE:-

UP POSITION:- SHORT CKT TESTED.

LTS OFF, CKT OK

ON, SHORT CKT

DOWN POSITION:- OPEN CKT TESTED.

LT ON, CKT OK.

LT OFF, OPN CKT.

TO RECTIFY THE SNAG REPLACE THE FIRE EXTINGUISHER BOTTLE OR CHK CONTINUITY FROM FIRE PROTECTION MODULE [P8] TO EXTINGUISHER BOTTLE.

 

OVHT/FIRE TEST:- IF ANY OF THE ENGINE FIRE HANDLE RED LT REMAINS OFF DURING THE FIRE TEST,CHK THE CONDITION OF THE CKT ON FIRE DETECTION MODULE ON E3-3 RACK.IF THE RESPECTIVE ENG FIRE/OVHT LT ON :- SHORT CKT.

IF ALL THE LTS ON ON MODULE E3-3 AND ON TEST THE RESPECTIVE ENGINE FIRE/OVHT LT REMAINS OFF THEN THERE IS AN OPEN CKT.

FIRE HANDLE PULLED:-

1.FUEL SOV CLOSES.2.HYD SOV CLOSES.3.LOP OF SYS A HYD INHIBITED [DEACTIVATED].4.GCR TRIPS.5.BLEED VALVE CLOSES.6.T/R ISOLATION VALVE DEENERGIZES.

7.FIRE BOTTLE ARMED.

FIRE EXTINGUISHING SYSTEM TROUBLESHOOTING:-

A.RH,LH OR APU BOTTLE DISCHARGE LT ON:-1.CHK BOTTLE PRESSURE,IF LOW REPLACE BOTTLE.2.IF OK, DISCONNECT ELECT CONN AND CHK CONTINUITY, THEN REPLACE PRESSURE SWITCH.

3.IF NOT,CHK WIRING FOR GROUNDS.

B.EXTINGUISHER TEST LT REMAINS OFF ON TEST:-

1.CHK BULB.

2.DISCONNECT ELECTRICAL CONNECTION TO SQUIB AND CHK FOR CONTINUITY WITH

OHMMETER ACROSS 1 & 2 PINS OF DISCHARGE SQUIB,NO CONTINUITY,REPLACE DISCHARGE SQUIB OR BOTTLE.

3.CONTINUITY OK,THEN DISCONNECT ELEC CONNECTION OF SELECTOR VALVE AND CHK CONTINUITY BETWEEN PINS 1 & 2 OF THE VALVE IF NO CONTINUITY REPLACE SELECTOR VALVE.

4.IF OK,CHK CONTINUITY OF WIRING FROM MODULE TO THE SELECTOR VALVE. NOTE:- STEP 3 NOT NEEDED IN CASE OF APU EXT AS THERE IS NO SELECTOR VALVE.

OVERHEAT DETECTION TROUBLESHOOTING:-

1.TEST SW TO OVHT POSITION.IF ENG OVHT LT FAILS TO ILLUMINATE,CHK OVHT INOP LT ON ENG AND APU FIRE DETECTION ACCESSORY UNIT.

2.IF OVHT LT NOT ILLUMINATING,REPLACE ACC.UNIT AND TEST SYSTEM.IF OVHT LT STILL NOT ILLUMINATED CHK CONDITION OF CONNECTOR,CHK SENSORS FOR OPEN [ON MULTIMETER TO CENTER CONDUCTER OF ELEMENT CONNECTER.IF RESISTANCE MORE THAN THE MAX VALUE,REPLACE SENSOR,IF OK.CHK WIRING FOR OPEN].CONNECTER RESISTANCE IS 1 ê/FTý APPROX.

3.IF OVHT INOP LT ILLUMINATED [E3 RACK].CHK SENSOR FOR SHORT CKT CONN.MEGER ACROSS CENTER CONDUCTER AND OUTER SHELL OF ELEMENT CONNECTOR.IF OK,CHK WIRING FOR SHORT CKT.

NOTE:- IF OVHT/FIRE INOP LT ON APU AND FIRE DET, ACC UNIT [E3] IS:-

ON:- CHK FOR SHORT CKT.

OFF:- CHK FOR OPEN CKT [OFF DURING TEST].

APU FIRE DETECTION/EXTINGUISHING SYSTEM MAY BE INOPERATIVE PROVIDE APU IS NOT USED.

ENGINE FIRE DETECTION TROUBLESHOOTING:-

1.TEST S/W TO FIRE POSN,IF FIRE Wx LT + ALARM FAILS TO OPERATE,THEN POSN OVHT DET S/W TO ON P8 MODULE TO FIRE AND HOLD TEST S/W TO FIRE.

2.IF FIRE Wx LT FAILS TO ILLUMINATE,CHANGE ENG FIRE DET.ACC UNIT [E3 RACK].

3.IF FIRE Wx LT + ALARM WORK THEN POSN OVHT DET S/W TO NORM AND CHK FIRE INOP LTS ON E3 RACK ACC UNIT.

4.IF FIRE INOP LT,NOT ILLUMINATING,REPLACE ACC UNIT AND TEST SYS,IF STILL NOT OK CHK CONDITION OF CONNECTER,SENSOR FOR OPEN CKT.

5.IF FIRE INOP LT ILLUMINATING,CHK SENSOR AND WIRE FOR SHORT CKT. APU FIRE DETECTION TROUBLESHOOTING:-

NOTE:- OPEN ENG #1 & #2,WING BODY OVHT AND WHEEL WELL CB.

1.HOLD TEST S/W TO FIRE.IF NO Wx,CHK APU DETECTOR INOP LT ON FIRE PROTECTION MODULE [P8].

2.NO INOP LT,REPLACE FIRE PROTECTION MODULE AND TEST AGAIN.IF STILL NO LT,THEN CHK SENSOR FOR OPEN CKT AND THEN WIRING FOR OPEN CKT.

3.IF INOP LT ON FIRE PROTECTION PANEL COMES ON ,THEN CHK SENSOR FOR SHORT CKT AND THEN WIRING FOR SHORT CKT.

LEFT WING BODY OVHT TROUBLESHOOTING:-

1.PRESS OVHT TEST S/W ON AIR COND PANEL ON P5.CHK LEFT WING BODY OVHT LT COMES ON.

IF LT DOES NOT COME ON:-

1.CHK BULB.[PTT].

2.CHK RESISTANCE VALUES BETWEEN PINS ON CONN OF WING BODY OVHT MODULE ON E3-2.

3.IF > 40 OHMS,DISCONNECT AND CLEAN CONNECTORS OF LOOPS.

4.IF < 40 OHMS,CHANGE WING BODY OVHT MODULE.

IF LT COMES ON AND DOES NOT GO OFF AFTER RELEASE OF OVHT TEST S/W:-

1.PUT OFF ENG/APU BLEED VALVE,CHK Wx LT.

2.IF LT GOES OFF,IT IS A GENUINE SNAG DUE TO LEAKING DUCT OR DETECTOR ELEMENT IS TOO CLOSE TO HOT DUCT.

3.IF IT DOES NOT GO OFF,HOLD S3 S/W ON MODULE IN UP POSITION ,IF THERE IS A SHORT CKT IN AFT LOOP,LT WILL REMAIN ON .

4.HOLD S2 S/W ON,IF THERE IS A SHORT CKT IN KEEL BEAM LOOP,THE LT WILL REMAIN ON.

5.HOLD S1 TEST SW ON MODULE,IF THERE IS A SHORT CKT IN AC PACK LOOP,LT WILL COME ON.

6.IF NO,CHK RESISTANCE WITH PIN 12,4 AND GRD,IF RESISTANCE < 10 OHMS THERE IS A SHORT CKT IN LHSTRUT + WING L/E LOOP.

7.CHANGE WING BODY OVHT MODULE ON E3-2 RACK.

Contents


ELECTRICAL

3 BASIC PRINCIPLES OF B737 ELECTRICAL POWER SYSTEM.

1.NO PARALLELING OF AC PWR SOURCE.

2.AC PWR SOURCE SWITCHED/ENTERING THE SYSTEM TAKES PRIORITY AND WILL TRIP OFF EXISTING SYSTEM.

3.SOURCE OF PWR DOES NOT ENTER THE SYSTEM AUTOMATICALLY.IT MUST BE MANUALLY S/WED ON WITH A S/W.

FOUR SOURCES OF AC POWER:-

GEN1,GEN2,APU GEN AND EXTERNAL POWER [GPU].THESE AC POWER SOURCES ARE CONNECTED TO BUSES BY INTERLOCKING SYSTEM OF SIX 3 PHASE BREAKERS.GB-1,GB-2,BTB-1,BTB-2,APU GB AND EPC.

INTERCHANGEABLE:-GB-1,GB-2,BTB-1,BTB-2 AND APU GB.[ALL EXCEPT EPC].

SYSTEM 1:- GEN 1 CONNECTED TO GEN BUS 1,MAIN BUS 1 AND TRANSFER BUS 1 THEN GB-1.

SIMILIARLY SYSTEM 2.

TO CHK RESIDUAL VOLTAGE OF GENERATOR,START ENGINE,RUN AT IDLE AND PUSH RESIDUAL VOLTAGE BUTTON.[NO RESIDUAL VOLTAGE INDICATOR ON MOTORING RUN].

ON GRD,WITH EXT PWR AVAILABLE,IF GRD PWR S/W ON P5 IS PUT ON:-

BOTH GB1 & GB2 TRIPS,BOTH BTB1 & BTB2 CLOSES,EPC CLOSES.

IF APU GEN S/W 1 PLACED ON:-

GB1 TRIPS,BTB1 CLOSES,APU GB CLOSES.

ON GROUND APU GEN CAN POWER BOTH SYSTEM 1 & 2 BUT IN FLT APU GEN CAN POWER ANY ONE OF THE SYSTEM.

TRANSFER RELAYS:-

P6 PANEL 3 POSTION.

NORMAL:- EITHER OF GB OR BTB CLOSED. ie GEN BUS 1 POWERS TRANSFER BUS 1.

ALTERNATE:- BOTH GB 1 & BTB 1 OPEN AND EITHER OF GB 2 OR BTB 2

CLOSED.ALTERNATE COIL ENERGISED,ie GEN BUS 2 POWERS TRANSFER BUS 1 THRU Tx RELAY 1.

OFF:- TRANSFER BUS NOT POWERED. ie BOTH GB AND BTB OPEN.

ELECTRICAL POWER SUB PANEL P5:-

GEN1 S/W CLOSES GB1.

GEN2 S/W CLOSES GB2.

L APU GEN S/W CLOSES APU GB AND BTB 1.

R APU GEN S/W CLOSES APU GB AND BTB 2.

GRD PWR S/W CLOSES EPC AND BOTH BTB1 & BTB2.

TRANSFER BUS OFF [AMBER]:- BOTH GB AND BTB OPEN.

BUS OFF [AMBER]:- BOTH BTB1 AND GB1 OPEN.

BUS OFF [AMBER]:- BOTH BTB1 & GB1 OPEN.

GEN OFF BUS [BLUE]:- GB1 OPEN.

APU GEN OFF BUS [BLUE]:- APU OVER 95% RPM BUT APU GEN NOT SELECTED.

DC POWER DISTRIBUTION:-

COMPONENTS :-

1.THREE 50 AMP TRANSFORMER RECTIFIER [TR] UNIT.2.A SINGLE 20 CELL,24V,22 AMP-HR Ni-Cd BATTERY.

3.A SINGLE 35 AMP,PULSE TYPE BATTERY CHARGER.

 IF ANY OF TR1 OR TR2 FAILS,TR3 WILL SUPPLY TO DC BUS1 [THRU A DIODE + RELAY] OR DC BUS2 [THRU A DIODE] SO,LOSS OF TR WILL NOT LEAD TO LOSS OF DC BUS.

IF TR3 FAILS,BATTERY BUS IS CONNECTED TO HOT BATTERY BUS,PROVIDEED BATTERY S/W IS ON.

NOTE:- DURING APU START, TO PREVENT ELECTRIC START MOTOR FROM DRAWING PART OF ITS HEAVY CURRENT THRU BATTERY CHARGER, AC INPUT TO BATTERY CHARGER IS INTERRUPTED BY APU START INTERLOCK RELAY R39.

HOT BATTERY BUS:-

POWERS ONLY FIRE EXTINGUISHER BOTTLES,ENG FSOV AND BACK UP FOR GCU. NORMALLY POWERED BY BATTERY CHARGER AND ALTERNATELY BY BATTERY.

BATTERY BUS:-

POWERS MOST OF INDICATING LIGHTS IN COCKPIT,MASTER CAUTION SYSTEM,FIRE DETECTION SYSTEM,PAX ADDRESS AMPLIFIER AND STANDBY POWER SYSTEM.BATTERY BUS IS NORMALLY POWERED FROM TR3 [MAIN BUS 2] AND ALTERNATELY [IFTR3 FAILS] BY HOT BATTERY BUS IF BATT S/W IS ON.

STATIC INVERTER RATING = 500VA.

STANDBY POWER DISTRIBUTION:-

2 STANDBY BUSES [1-AC AND 1-DC].NORMALLY ALWAYS POWERED.

STANDBY AC BUS:- 1í 115V AC, POWERED BY PHASE A OF TRANSFER BUS 1,IF TX BUS 1 FAILS, BATTERY WILL SUPPLY TO STANDBY AC BUS THRU STATIC INVERTER [PROVIDED STANDBY PWR S/W IN AUTO POSITION].

STANDBY DC BUS:- 28VDC POWERED BY DC BUS1,IF DC BUS 1 FAILS,BATTERY WILL DIRECTLY SUPPLY STANDBY DC BUS.

STANDBY POWER S/W:- 3 POSITION BATT-OFF-AUTO, NORMALLY IN AUTO POSITION.

IN FLT LOSS OF NO 1 TRANSFER BUS WILL RESULT IN STATIC INVERTER TURNING ON AND SUPPLY STANDBY AC BUS.ON GRD THIS WILL NOT HAPPEN, AS ALTERNATE SUPPLIES TO STANDBY BUSES ARE LOCKED OUT BY AIR GRD SENSOR TO AVOID STANDBY PWR DRAINING AIRCRAFT BATTERY. IF STANDBY S/W IS IN OFF POSITION STANDBY PWR OFF AMBER LIGHT WILL COME ON.

IF STANDBY S/W IS PLACED TO BATT POSITION, THEN BATTERY WILL SUPPLY TO DC STANDBY BUS AND STATIC INVERTER WILL SUPPLY TO AC STANDBY BUS. THIS POSITION IS NECESSARY FOR SERVICEABILITY OF STATIC INVERTER ON GRD AS WELL AS FUEL INDICATION DURING REFUELLING WITH NO ELECTRIC POWER AVAILABLE.

BATTERY CHARGER:- 35 AMP, PULSE TYPE.

AC CONTROL AND PROTECTION:-

GENERATOR CONTROL UNIT [GCU] CONTAINS FOLLOWING ITEMS:-

FIELD PWR SUPPLY [TR UNIT] WHICH CONVERTS 3í AC PWR FROM GEN TO RIPPLED DC FOR GENERATOR EXICITER.

CONTROL DC PWR SUPPLY [TR OUT] FOR PROTECTION CKT.

VOLTAGE REGULATOR.

GCR WHICH CONNECT OUTPUT OF FIELD PWR SUPPLY TO GEN EXICITER.

TRANSISTORIZED PROTECTION CKT FOR:-

OVERVOLTAGE [OV]UNDERVOLTAGE [UV]OVERFREQUENCY [OF]UNDERFREQUENCY [UF]OVERCURRENT [OC]

DIFFERENTIAL CURRENT PROTECTION [DP]

GCR OPN:- PRIMARY FUNCTION OF GCR IS TO CONNECT FIELD SUPPLY TO GEN EXICITER.

7 WAYS TO TRIP GCR:-MANUAL:-

GEN S/W TO OFF

FIRE HANDLE PULLED [7 SECS T/D]

CSD DISCONNECT S/W

AUTOMATIC:-

OVERVOLTAGE 130ñ3V

UNDERVOLTAGE 100ñ3V

OVERCURRENT 170 AMPS

DIFFERENTIAL CURRENT PROTECTION 20 AMPS

POWER READY RELAY

GENERATOR BREAKERS:-

GB CAN BE CLOSED BY;-

PLACING GEN S/W TO ON, ENERGISING POWER READY RELAY AND TRIPPING NECESSARY BREAKERS TO PREVENT PARALLELING.

GB CAN BE TRIPPED BY:-

TRIPPING GCR [3 MANUAL WAYS + 4 AUTOMATIC WAYS]OVERFREQUENCY 430ñ5 cpsUNDERFREQUENCY 370ñ5 cps

NOTE:-OVERFREQUENCY OR UNDERFREQUENCY DOES NOT TRIP GCR.

BTB:-

BTB CAN BE TRIPPED BY:-

ENG GEN S/W TO ON

APU GEN S/W TO OFF

ANY ACTION WHICH TRIPS APU GB AND EPC LIKE GRD POWER S/W TO OFF,APU GEN FAULTS,EXT POWER FAULTS ETC.

PRIORITY OF FAULTS TRIPPING GB OR GCR:-

OVERCURRENT > UNDERFREQUENCY > UNDERVOLTAGE

ANNUNCIATOR SIGNALED TROUBLESHOOTING:-

1.HV LIGHT COMES ON:-

DEFECTIVE GCU.

2.LV LIGHT COMES ON:-

DEFECTIVE GENERATOR.DAMAGED CSD SHAFT OR SPLINE.

DEFECTIVE GCU.

3.FF [FEEDER FAULT] LT COMES ON FOLLOWED BY GCR,GB TRIPPING:-

DEFECTIVE CT.DEFECTIVE GCU.

OVERCURRENT CONDITION CHK LINES FOR FAULT.

4.MT [MANUAL TRIP] SIGNAL COMES ON:-

DEFECTIVE CKT TO MANUAL TRIP OR GCR FROM GEN S/W.

.

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