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737-200 AIRCRAFT NOTES PART 1.

 

Notes Prepared from B737-200/P&W JT8D MM Between 12th June 1994 to 10th October 1994.

By Mr Meljoe Ferreira

 

Contents

ENGINEENGINE LIMITATIONS

MAINTENANCE TIPS

ENGINE TROUBLESHOOTING

APU TROUBLESHOOTING

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ENGINE

IF THERE IS A CAN SHIFT IT WILL LEAD TO SLOW ACCELERATION. THE TIME TAKEN TO ACCELERATE FROM IDLE TO T/O PWR WILL BE MORE.

NORMALLY ENGINE SHOULD ACCELERATE TO IDLE RPM WITHIN 2 MINS, OTHERWISE MOVE START LEVER TO CUT-OFF.

MAINTENANCE -9A/17A

1ST HSI --- 5500 CYCLES

H.M. --- 10,400 CYCLES

2ND HSI --- 16,000 CYCLES

SUBJECT TO NOT MORE THAN 5500 CYCLES FROM H.M.

T.B.O. --- 18,000 CYCLES

LIFE DEVELOPMENT PROGRAMME

1ST HSI --- NIL

H.M. --- NIL

2ND HSI --- 16,000 CYCLES

T.B.O --- 21,000 CYCLES

NOZZLE COKE CLEARANCE:- IN-SITU CHECK EVERY ALTERNATE CHK C OR 1000 HRS.

APU LIFE:-

T.B.O --- 3000 RUNNING HRS OF A.P.U.

O/H --- 3000 / 1.8 FLT HRS.

LIFE DEVELOPMENT --- 3500 APU HRS.

PNEUMATIC STARTER DUTY CYCLE:-

NORMAL:- 30 SECS ON, 60 SECS OFF.SLOW STARTING ENGINE:- 60 SECS ON, 60 SECS OFF. [35-45% N2 RPM].EXTENDED DUTY CYCLE CAN BE REPEATED ONCE AND THEN COOLING PERIOD GIVEN.

FOR MOTORING:- 2 MINS ON, 5 MINS OFF.

Contents


ENGINE LIMITATIONS

-9A ENGINE N1 N2

OPERATING LIMIT 100.1% 100%

OVERSPEED LIMIT 104.4% 102.5%

-17/17A ENGINES

OPERATING LIMIT 102.4% 100%

OVERSPEED LIMIT 104.4% 102.5%

IF ACTUAL SPEED MORE THAN OPTG LIMIT BUT LESS THAN O/S LIMIT THEN:-

1.VISUALLY INSPECT ENGINE.

2.CHECK FOR FREEDOM OF ROTATION OF BOTH ROTORS.

3.DETERMINE CAUSE OF OVERSPEED.

CONTINUE ENGINE IN SERVICE IF EVERYTHING FOUND SATISFACTORY.

IF ACTUAL SPEED > O/S LIMITS:-

1.REMOVE ENGINE AND SEND FOR OVERHAUL.

OIL LIMITATION

IF CHIP DETECTOR IS FOUND MISSING AT OUTSTATION A/C CAN BE FLOWN TO BASE BY QC PERMISSION.

OIL CAPACITY:- 4.5 U.S.GALLONS.

MOBILE JET II OR PWA 521 SPEC.

OIL SERVICING:-WITHIN 30 MINS OF ENGINE SHUT DOWN, SERVICED TO 3 USG MARK [2.25 TO 3.25 ACCEPTABLE]

OIL FILTER:- 10 TO 15 MICRON DISPOSABLE TYPE.

 

OIL CONSUMPTION

NORMAL:- 1.5 TO 2 US PINTS/HR.

MAXIMUM:-

FOR #4 LABRYNTH SEAL --- 0.5 USG/HR.

FOR #4 CARBON SEAL --- 0.25 USG/HR.

INVESTIGATE IF OIL CONSUMPTION IS MORE.

BREATHER PRESSURE LIMIT:-

IT IS THE DIFFERENCE OF PRESSURE AT GEARBOX AND OUTLET OF BREATHER PORT.

BREATHER PRESSURE CHECKED AT T/O EPR.

IF B.P. IS HIGH:-IT INDICATES INEFFICIENT SEALING ie MIXING OF HOT AIR WITH OIL WHICH INCREASES SPECIFIC VELOCITY BUT DECREASES SPECIFIC DENSITY.

MAX BREATHER PRESSURE:-

1.#4 BEARING WITHOUT CARBON SEAL

-9A ENGINE --- 3.1 PSIG OR 8" OF Hg.

-17A ENGINE --- 4.2 PSIG OR 8.5" OF Hg.

2.#4 CARBON SEAL BEARING.

OIL PRESSURE

1.NORMAL:-40 TO 50 PSI.

2.IF OIL PRESSURE < 40 BUT >/ 35 PSI, INVESTIGATE AND RECTIFY THE SNAG BEFORE

RELEASING THE AIRCRAFT.

3.IF OIL PRESSURE < 35 PSI, SHUTDOWN ENGINE IMMEDIATELY [OR IN FLIGHT REDUCE THRUST TO MIN]

OIL TEMPERATURE

CONT OPTG LIMIT MAX

-9A 120øC 157øC

-17/17A 130øC 165øC

[A] IF OIL TEMP IS MORE THAN CONTINUOUS OPTG LIMIT BUT EQUAL TO MAX LIMIT FOR A PERIOD NOT MORE THAN 15 MINS:-

1.DETERMINE CAUSE AND RECTIFY.

2.CONTINUE IN SERVICE.

[B] OIL TEMP > CONTINUOUS OPTG LIMIT FOR MORE THAN 15 MINS:-

1.DRAIN OIL

2.CHK OIL FILTERS + MAG CHIP DETECTER.

3.RECTIFY SNAG AND CONTINUE IN SERVICE.

[C] OIL TEMP > MORE THAN MAX LIMIT SEND FOR OVERHAUL.

NO ACTION REQUIRED IF OIL TEMP > CONT OPTG LIMIT BUT \< MAX LIMIT FOR A PERIOD NOT EXCEEDING 15 MINS WHEN THROTTLE IS RETURNED AT THE END OF CRUISE AND START OF DESCENT.

VIBRATION LIMITS:-

TEST BED LIMITS

INLET --- 2 UNITS

TURBINE --- 1.5 UNITS

IF EXCESSIVE VIBRATION REPORTED, CHK THE FOLLOWING:-

1.QUAD RING ON CSD.

2.QUAD RING ON FCU.

3.TIGHTNESS OF ENGINE MOUNT.

4.MOUNTING OF HYDRAULIC PUMP FOR LOOSENESS.

5.INLET COWL FOR LOOSENESS.

6.THRUST REVERSER DOOR OPEN AND DAMAGE.

7.REMOVE,CLEAN VIBRATION PICKUP PLUGS.

8.INLET AND EXHAUST AREA FOR DAMAGE.

EGT LIMITATIONS:-

T/O -9A 590øC

-17/17A 650øC

MAX CONT -9A 545øC [TO BE USED ONLY

-17/17A 610øC DURING EMERGENCY]

MAX CRUISE -9A 520øC

-17A 580øC

IDLE NO LOAD 420øC

WITH LOAD 480øC

STARTING -9A [OAT < 15øC] 350øC

[OAT > 15øC] 420øC

-17 550øC

-17A 575øC

THESE TEMP ARE TIME LIMITED TO MOMENTARILY [NOT EXCEEDING 15 SEC] FOR STARTING.

IF MAX ALLOWABLE STARTING TEMP IS EXCEEDED, SHUTDOWN ENGINE AND INSPECT IN ACCORDANCE WITH CHAPTER 72 OF MM.

STARTING PERIOD ENDS WHEN N2 STABLIZES.

ACCELERATION

-9A 590øC

-17A 650øC

THESE ARE TRANSITORY EGT INDICATION. EGT MUST STABLIZE WITHIN 2 MINS.

FUEL/OIL LEAKAGE:-

CLEAN SUSPECTED AREA

FOR OIL LEAKS RUN ENGINE FOR 5 MINS AT T/O EPR.

FOR FUEL LEAKS RUN ENGINE AT T/O FOR 5 MINS, SHUTDOWN MONITOR FUEL BOOST PRESSURE TO MAIN FUEL PUMP INLET. SUSPECTED AREA MUST BE CLEANED AND INSPECTED AFTER 15 MINS.

1.STAIN 1 «" AFTER 15 MINS.2.SEEP 4" AFTER 15 MINS.3.HEAVY SEEP 6" AFTER 15 MINS.

4.RUNNING LEAK CONTINUOUS.

NOTE:- LEAK IS NORMALLY ALLOWED FROM

1.UPPER/LOWER WING SURFACES

2.FRONT AND REAR SPARS

3.DRY BAY

NO LEAK ALLOWED FROM WING CENTER SECTION.

PNEUMATICS SYSTEMS:-

ENGINE BLEED :- 62 PSI,450øF

APU :- 36PSI,442øF

GRD CART :- 60 PSI,450øF

EACH PACK :- 80 lbs/min

ENG STARTING :- 110 lbs/min

WING ANTI-ICING :- 120 lbs/min

APU BLEED VALVE :- MODULATING TYPE, SOLENOID CONTROLLED. MSOV WILL START CLOSING AT 65% N2 RPM AND DUCT PRESSURE 20 PSI.

EGT:-

-9A ENGINE:-ON COLD DAY,IF EGT IS 420øC REGARDLESS OF DURATION:-

1.DETERMINE CORRECT CAUSE OF OVERTEMP.

2.ENTER INTO ENG LOG.

3.VISUALLY INSPECT EXTERIOR OF ENGINE AND INTERIOR OF EXHAUST DUCT.

NOTE:-UPTO 455øC ABOVE PROCEDURE TO BE FOLLOWED.

IF 590øC PERFORM HSI.

T/O EGT 590øC.

ACCN EGT 590øC.[2 MINS].

1.UPTO 590øC NO MAINTENANCE REQUIRED AS PER MM.

2.BETWEEN 590 TO 620øC WITH DURATION OF 5 SECS OR LESS:-

A.DETERMINE CAUSE OF OVERTEMPERATURE.

B.VISUALLY CHECK EXH DUCT FOR BURNING CONDITION, METAL PARTICLES.

C.INSPECT ENG INLET FOR EVIDENCE OF BLADE OR VANE DAMAGE.

-17A ENGINES:-

START EGT:- 575øC

T/O EGT:- 650øC

ACCn:- 660øC

START EGT 575øC:- NO ACTION REQUIRED.

T/O EGT 650øC:- NO ACTION REQUIRED.

ACCn EGT 650øC:- [LESS THAN 2 MINS] NO ACTION REQUIRED.

[MORE THAN 2 MINS] PERFORM H.S.I.

THROTTLE STAGGER:-

THROTTLE STAGGER OF 1-1/2 KNOBS OR LESS MUST BE CORRECTED AT THE EARLIEST POSSIBLE TRIM OPPORTUNITY.

MORE THAN 1-1/2 KNOBS MISALIGNMENT AT T/O PWR SHOULD BE CORRECTED BEFORE RELEASING AIRCRAFT FOR FLIGHT.

F.O.D:-

1.INSPECT 1st STAGE BLADES FOR SHINGLING, IF ANY CRACKS ON THE BLADES DETECTED, REPLACE AFFECTED BLADES [BLADES COME IN SETS OF THREE].

2.NO DAMAGE ALLOWED AT OR NEAR MIDSPAN SHROUD AND ROOT AREA.

3.UNSHINGLING DONE WITH A WOODEN BLADE. SHINGLED BLADES MUST BE REPLACED WITHIN 20 FLT HRS.

4.CHECK INLET/EXHAUST AREA FOR ANY DAMAGE.

5.CHECK Pt2 PROBES,Tt2 PROBES FOR DAMAGE OR BLOCKAGE.

6.CHECK CSD OIL COOLER FOR DAMAGE, BLOCKAGE.

7.BLOW CDP LINE.

8.CARRY OUT SOFT INJECTION INSPECTION SCHEDULE.

9.CARRY OUT ENGINE GROUND RUN-UP AND MONITOR ALL PARAMETERS WITHIN LIMITS

[ESPECIALLY INLET AND TURBINE VIBRATION]

CSD IN TEMP GAGE GIVES INDICATION OF CSD OIL COOLER CONDITION.

IF ENGINE START WAS ABORTED DUE TO HUNG START:-

1.CHK TURBOFAN VALVE AND AIR PURGE VALVE [IF THEY ARE OPEN WITH PACKS OFF THE BLEED PRESSURE MAY NOT BE SUFFICIENT FOR ENGINE STARTING]

2.MANUALLY CLOSE THE TURBOFAN VALVE FOR ENGINE STARTING.

HIGH OIL PRESSURE:-SENSE LINE TO PRV MAY BE OBSTRUCTED/BLOCKED.

ENGINE STARTS NORMALLY BUT DOSE NOT ACCELERATE TO IDLE [HUNG START]:-

1.AIR ENTRAPPPED IN FCU. MOVE THROTTLE FWD.

2.CDP SENSE TO FCU BLOCKED/LEAK.

3.SURGE BLEED VALVE OPEN.

4.P & D VALVE.

5.PNEUMATIC STARTER CUTOUT.

BIRD STRIKE INSPECTION:-

1.EXAMINE WINGS, NACELLES, STRT, HORIZONTAL AND VERTICAL STABLIZER. L/E FOR DAMAGE, FASTNER HOLE ELONGATION, TEAR OUT ,CRACKS ETC. CHECK WING L/E AND T/E STRUCTURE PANELS, BOTH SIDES HONEYCOMB PANELS FOR CRACKS, DELAMINATION ETC.

2.CHECK L/E AND T/E FLAPS MECHANISM FOR DISTORTION, CRACKS, MISALIGNMENT ETC.

3.CHECK CONTROL SURFACES FOR FREE AND FULL MOVEMENT, DISTORTION, BINDINGS, PULLED FASTNERS.

4.CHK NOSE AND MAIN GEAR DOORS AND LINKAGE.

5.COCKPIT WINDOWS FOR DELAMINATION OR CRACKS.

6.CHK RADOME AND FWD BODY NOSE SECTION FOR DAMAGE.

7.EXAMINE NOSE COWL AND NOSE DOME ON THE ENGINE FOR DENTS, CRACKS, BUCKLING, PULLED OR MISSING FASTNERS, DAMAGE TO Pt2,Tt2 PROBES ETC.

8.EXAMINE ENGINE FOR BENT, CRACKED OR BROKEN FAN AND COMPRESSOR BLADES ,EGT PROBES,PT7 PROBES, OIL LEAKS, PLUGGED RAM AIR INLETS, CSD OIL COOLER, PLUGGED PS3 FILTER ETC.

9.INLET AND EXHAUST AREAS FOR GRD CONDITION. IF ENGINE APPEARS SERVICEABLE OPERATE ENGINE ENSURE THAT T/O PWR AVAILABLE AND RECORD ALL ENGINE PARAMETERS INCLUDING INLET AND TURBINE VIBRATIONS.

MOTORING ENGINE:-

REQUIREMENTS

1.UNSATISFACTORY START TO CLEAR THE ENGINE OF TRAPPED FUEL AND VAPOURS.

2.TO BLEED AND DEPRESSURISE THE ENGINE FCU.

3.TO PRESERVE THE CSD.

STARTER DUTY CYCLE:-2 MINS ON,5 MINS OFF.

IF THE STARTER SWITCH IS RETURNED TO OFF PRIOR TO END OF MOTORING RUN, IT MUST NOT BE ENGAGED UNTIL 30 SECS AFTER ENGINE AND STARTER HAVE STOPPED ROTATING.

DURING MOTORING CHECK:-

1.N1 AND N2 INDICATORS FOR CORRECT READING.

2.OIL PRESSURE INDICATORS [TOWARDS END OF MOTORING RUN, THE LOP LT SHOULD GO OFF].

BREATHER PRESSURE:-

BREATHER PRESSURE BETWEEN 5.1 TO 7.1" Hg:- CARRY OUT B.P.CHECK EVERY 500 HRS.

BREATHER PRESSURE > 7.13" OF Hg [3.5 PSI]:-REPEAT WITH BREATHER DUCT

REMOVED,IF STILL HIGH CHANGE ENGINE.

BREATHER PRESSURE CHK:- [C/O EVERY 1000 HRS]

B.P.CHECK HAVE TO BE CARRIED OUT WHENEVER A SNAG OF HIGH OIL PRESSURE/TEMPERATURE, OR EXCESSIVE OIL CONSUMPTION IS REPORTED AND CARBON SEAL FAILURE IS SUSPECTED. IT GIVES A FAIR IDEA OF INTERNAL CONDITION OF ENGINE.

1.DISCONNECT BREATHER DUCT FROM ENG GEARBOX.

2.REMOVE OIL TANK CAP AND FIT A PRESSURE GAGE 0 TO 30 PSIG.

3.START ENGINE AND STABLIZE AT IDLE FOR 5 MINS. ACCELERATE TO T/O PWR SLOWLY. RECORD B.P. READING FROM THE GAGE AFTER 2 MINS AT T/O PWR

4.COMPARE IT WITH MAXIMUM LIMIT

MAX LIMIT

JT8D-9A ENGINE 8.0 in Hg [4 psi]

[WITHOUT #4 CARBON SEAL][PRE SB 5250]

JT8D-17/17A ENGINE

[WITHOUT #4 CARBON SEAL] 8.5 in Hg [4.25 psi]

ALL JT8D ENGINES

[WITH #4 CARBON SEAL] 7.13 in Hg [3.5 psi]

DO NOT RETURN THE ENGINE TO SERVICE IF IT HAS HIGH BP WHICH IS AN INDICATION THAT HIGH TEMP, HIGH PRESSURE AIR MAY BE LEAKING INTO BEARING COMPT CREATING A POTENTIALLY DANGEROUS SITUATION. TO MINIMIZE AIRCRAFT SKIDDING WHEN ENGINES ARE OPERATING AT HIGH POWER ENSURE AIRCRAFT SATISFIES MINIMUM GROSS WT REQUIREMENTS.

THRUST CONDITION MIN GROSS WT

1.ONE ENG AT T/O PWR 79,000 lbs

OTHER AT 1.2 EPR

2.BOTH ENGS AT 80% T/O EPR 63,000 lbs

3.BOTH ENGS AT T/O PWR 79,000 lbs

COMBUSTION CHAMBER CASE RUPTURE:-

OPERATIONAL INDICATOR FOR COMBUSTION SECTION DISTRESS.

1.SLOW START [>30 SECS FROM LIGHT OFF TO IDLE]

2.SLOW ACCELERATION ABOVE IDLE.

3.EXCESSIVE AND REPETITIVE THROTTLE STAGGER.

4.LOW IDLE SPEED.

NORMAL JT8D ENGINE START TIME:-

22 SECONDS [SPOOLING FROM LIGHT OFF TO IDLE]. MAX ALLOWABLE IS 30 SECONDS.

SLOW ACCELERATION:-

WITH BOTH ENGINES PROPERLY TRIMMED, WHEN THRUST LEVER IS ADVANCED TO MID THROTTLE POSITION THEY SHOULD STABLIZE WITHIN 3 SECONDS OF EACH OTHER.

T.C. B-24/B-16 OF 1990

LOSS OF OIL FROM MAIN GEARBOX PARTING SURFACES BECAUSE OF G/B STUD GETTING LOOSE. CHECK FOR PHYSICAL PRESENCE OF ALL G/B STUDS DURNG CHK B IF STUD OBSERVED TO BE LOOSE, NO ATTEMPT TO RECTIFY OIL LEAK BY TIGHTENING G/B STUD OR EXTERNAL NUT SHOULD BE MADE [OVER-TIGHTENING MAY CAUSE DAMAGE IN MAGNESIUM PARENT MATERIAL.

Contents


 

ENGINE TROUBLESHOOTING

A.LOW OIL PRESSURE:-

1.CHK OIL QTY.

2.CHK OIL PRESSURE INDICATOR, TRANSMITTER, ELECTRICAL CONNECTIONS. CHK FOR RESTRICTING ORIFICE PLUGGING.

3.CHK PR RELIEF VALVE. DRAIN OIL, REMOVE OIL PR RELIEF VALVE. EXAMINE FOR SEAL DAMAGE. INSPECT VALVE FOR INTERNAL BINDING.

4.DEFECTIVE MAIN OIL PUMP. REMOVE PUMP, CHK PACKING FOR DAMAGE. CHK PUMP CASING FOR SCORING. CHANGE PUMP IF DEFECTIVE.

B.HIGH OIL PRESSURE:-

1.CHK OIL PR INDICATOR, Tx, ELECT CONN AND RESTRICTION ORIFICE FOR PLUGGING.

2.CHK PR RELIEF VALVE, DRAIN OIL, REMOVE PRV, CHECK PACKINGS CHANGE VALVE IF INTERNAL BINDING OBSERVED.

3.CHK FOR OBSTRUCTION IN PR SENSE LINE [BY BLOWING WITH NITROGEN]

4.CARRY OUT BREATHER PR CHK. REPLACE ENGINE IF B.P. BEYOND LIMIT.

C.FLUCTUATING OIL PRESSURE:-

1.CHK OIL PR INDICATOR, Tx, ELECT CONN.

2.CHK FOR DEFECTIVE PRV.

3.CHK FOR MISSING RESTRICTOR ORIFICE IN PR LINE TO Tx.

4.CHK OIL QTY.

D.OIL PRESSURE FOLLOWING THROTTLE:-

1.DEFECTIVE OIL PRV.

E.OIL FILTER BYPASS LT COMES ON:-

1.DEFECTIVE INDICATION SYSTEM [LOP S/W, INDICATING AMBER LT +ELECTRICAL CONN].

2.MAIN OIL FILTER CLOGGED. IF FILTER CLOGGED, REPLACE WITH NEW FILTER CARRY OUT GRD RUN AT PP FOR SEVERAL MINS ACCELERATE SEVERAL TIMES. CHK OIL FILTER AFTER SHUTDOWN, FILTER CLEAN RELEASE THE AIRCRAFT, IF NOT CLEAN REPEAT THE PROCESS WITH NEW FILTER. IF STILL NOT CLEAN SEND ENGINE FOR INVESTIGATION.

3.CHK ALL 4 MAGNETIC CHIP DETECTORS [MCD] IF METAL PARTICLES FOUND RECHECK AFTER 25 HRS/50 HRS. IF METAL PARTICLES FOUND AGAIN SEND ENGINE FOR OVERHAUL.

4.TAKE OIL SAMPLE FOR SOAP [SPECTROMATIC OIL ANALYSIS PROGRAMME] TEST.

5.PERFORM BREATHER PRESSURE CHECK.

F.HIGH/FLUCTUATING OIL TEMPERATURE:-

1.CHK FOR LOW OIL QTY.

2.DEFECTIVE TEMP INDICATOR, TEMP BULB OR ELECT CONN, REMOVE TEMP BULB AND HOLDIN AIR, GAGE SHOULD READ AMBIENT TEMP.

3.FUEL DEICING VALVE STUCK OPEN. START ENGINE RAISE PWR TO 1.4 EPR, OPEN FUEL DEICING VALVE, CHK FOR 0.02 TO 0.03 EPR DROP AND OIL TEMP RISE IF NO EPR DROP OR OIL TEMP RISE OBSERVED CHANGE FUEL DEICING VALVE.

4.FCOC BYPASS VALVE OPEN. INSTALL PRESSURE GAGE [0 TO 1000] BEFORE FCOC.START ENGINE DIFF OIL PRESSURE READING ON COCKPIT GAGE AND GAGE ON THE ENGINE OF 34 PSI SHOWS FCOC CLOGGED, REPLACE IT.

5.CHK OIL SYSTEM FOR CONTAMINATION.

a]CHECK OIL FILTER.

b]CHK OIL MCD FOR METAL PARTICLES.

c]CHK FOR OIL DISCOLOURATION, SEND SAMPLE FOR SOAP TEST.

d]PERFORM BREATHER PRESSURE CHECK, REPLACE ENGINE IF BP ABOVE LIMITS.

G.EXCESSIVE OIL CONSUMPTION:-

1.EXTERNAL TUBING LEAKAGE,CHK OIL PR BEARINGS AND BREATHER LINES FOR OIL LEAKS.

2.OIL DISCHARGE AT OVERBOARD BREATHER PORT.CHK FOR OVERSERVICING AND DE-OILER SEAL FOR DAMAGE.

3.CHK FOR OIL LEAKAGE AT G/B PARTING SURFACE,G/B ACC DRIVE [COMPONENT] SEALS.

4.OIL WETTING IN GASPATH, INSPECT INLET AND EXHAUST AREA FOR OIL WETTING. DISASSEMBLE ADJACENT BEARING AREAS AND CHK FOR CARBON SEAL FAILURE [O/H].

5.CARRY OUT BREATHER PR CHK HIGH BP WILL CAUSE EXCESSIVE OIL CONSUMPTION. BLEED SYSTEM

H.BLEED NON OPERABLE OR OFF SCHEDULE.

1.CHK PRBC VENT SCREEN FOR CLOGGING.

2.CHK PRBC TUBES FOR LEAKS,CRACKS,TIGHTNESS[PS3,PT2 AND PS4 TUBINGS].

3.CHK PS3 FILTER FOR CONTAMINATION.

4.DEFECTIVE BLEED VALVES. DISCONNECT BV ACTUATING PR [PS4] LINE AT DIFFUSER CASE AND CONNECT TEST HOSE. BLOW AIR INTO TEST HOSE WITH MOUTH AND LISTEN FOR BLEED VALVE CLOSURE NOISE.IF NO CLOSURE NOISE HEARD BUT PRESSURE BUILDUP INDICATES PS4 LINE OK THEN REPLACE ENGINE AS BLEED VALVE INOPERABLE. SIMILIARLY CHK 13TH STAGE BLEED VALVE [SB5425].

5.INADEQUATE/EXCESSIVE PS3 SENSE PRESSURE,CONNECT 0 TO 50 PSIG GAGE TO PS3 TEST PORT,START ENGINE,ACCELERATE TO N1 JUST ABOVE BV CLOSING,PR SHOULD BE 4 TO 6 PSI.

6.DEFECTIVE PRBC,IF BV DOES NOT OPERATE OR ARE OFF SCHEDULE AND CHK 1 TO 5 SHOWS A DEFECT THEN PRBC IS FAULTY.

7.DEFECTIVE START BLEED CNTRL VALVE [POST SB 5425].DISCONNECT BOTH INLET AND OUTLET LINES, CONN NITROGEN PR BOTTLE AND RAISE PR TO 17 TO 25 PSI AND CHECK FOR RISE IN PRESSURE AT OUTLET LINE DUE OPENING OF START BLEED CNTRL VALVE, IF NOT REPLACE IT.

INDICATION SYSTEM

I.EPR INDICATION FLUCTATION:-

1.CHK FOR LOOSE PT2 LINE CONNECTIONS IN NOSE CONE AND INLET CASE STRUT CONNECTOR PACKING FOR CONDITION.

2.LOOSE CONN IN PT2,PS3 OR PS4 LINES TO PRBC.

3.BROKEN INLET CASE PT2 LINE.CHK FOR LEAKS.

J.EPR DROPS EXCESSIVELY WHEN ANTI ICE IS SELECTED.

1.LOOSE/PLUGGED PT2 PASSAGE IN NOSE DOME.

2.DEFECTIVE ANTI ICE SOV OR ACTUATOR.

K.LOW EPR-EGT REACHES REDLINE BEFORE ENGINE REACHES REQD EPR.

1.DEFECTIVE EPR INDICATING SYSTEM.

2.DEFECTIVE EGT INDICATING SYSTEM.

3.PT7 LINE LOOSE AT EXHAUST CASE.

4.OBSTRUCTED PT7 LINE TO EPR Tx.DISCONNECT LINES AND BLOW WITH NITROGEN PRESSURE.

5.OBSTRUCTED PT7 PROBES/MANIFOLD.BLOW THEM WITH 10 PSI NITROGEN PR AND FEEL FOR AIRFLOW AT PT7 PROBE.

6.LEAKING PT7 SYSTEM.

L.NO N1 OR N2 INDICATION.

1.CHK COMPRESSOR ROTOR FOR FREE ROTATION.CHK INLET AND EXHAUST AREA FOR DAMAGE FROMROTOR SEZIURE.

2.DEFECTIVE INDICATOR OR TACHOGENERATOR.

NOTE:- TO SEGREGATE INDICATION PROBLEMS FROM GENUINE ENGINE SNAGS, IT SHOULD BE KEPT IN MIND THAT ANY ABNORMAL PARAMETER SHOWING OF EITHER F/F,EPR,EGT,N1,N2 OR OIL PR AND TEMP INDICATIONS WILL HAVE AN EFFECT ON OTHER ENGINE PARAMETERS. BUT IF ANY ONE OF THE ABOVE PARAMETERS SHOWS ABNORMAL READING [WITH OTHERS NORMAL] IT IS AN INDICATION SYSTEM PROBLEM.

FUEL SYSTEM

M.NO FUEL FLOW WITH START LEVER IN IDLE POSITION.

1.CHK THAT FIRE HANDLE IS NOT PULLED.2.CHK OPN OF FUEL SOV,APPLICABLE FUEL BOOSTER PUMP OPN.3.DEFECTIVE FUEL PUMP,CONNECT 0 TO 300 PSIG GAGE TO PUMP OUTPUT.MOTOR ENGINE,CHK FUEL PRESSURE [> 130 PSI + PUMP INLET PR]. 4.IF NO PR INDICATION,THEN CHK FOR SHEARED FUEL PUMP DRIVE SHAFT SPLINE.

5.IF PUMP OK THEN REPLACE FCU.

N.HUNG START [NO ACCELERATION TO IDLE]

1.INADEQUATE BLEED PRESSURE.

2.PREMATURE STARTER CUTOUT.

3.IMPROPER SURGE BLEED VALVE OPN.

4.DEFECTIVE FCU.CHK PS4 SENSE LINE TO FCU FOR LEAKS,DRAIN CDP,MOISTURE TRAP.BLOW CDP LINE,CHK SILICONE OIL LEVEL,TOP IT UP.IF SNAG PERSIST,CHANGE FCU.

O.IMPENDING HOT START.

1.INADEQUATE BLEED PRESSURE FOR STARTING THE ENGINE,CHK FOR APU BLEED PR WITHOUT LOAD,CHK FOR BLEED LEAKS.

2.CHK SURGE BV OPEN.BV REMAINING CLOSED MAY CAUSE HOT START.

3.CHK INLET AND EXHAUST AREAS FOR GASPATH DAMAGE.REPLACE ENGINE IF DAMAGE FOUND.

4.CHK FOR FUEL CONTROL SCHEDULE SHIFT BY COMPARING F/F OF BOTH ENGINES.REPLACE FCU IF ANY ABNORMAL DIFFERENCE IN FLT.

5.CHK FOR PREMATURE OPENING OF FUEL P & D VALVE.

P.SLOW START.

SLOW START IS EXCESIVE TIME BETWEEN LIGHT OF AND IDLE > 30 SECS.

1.INADEQUATE BLEED PRESSURE FOR STARTING,IF BOTH ENGINES HAVE A TENDENCY TO SLOW START,APU MAY NOT BE TAKING LOAD [REF APU TROUBLESHOOTING].

2.IMPROPER STARTING PROCEDURE.START LEVER MOVED TO IDLE BEFORE N2 REACHES 18 TO 20 %

3.CHK PS4 LINE FOR LEAKS,RESTRICTION.DRAIN CDP MOISTURE TRAP,TOP UP SILICON OIL.

4.CHK P & D VALVE FOR PREMATURE SECONDARY FUEL FLOW .

5.IMPROPER BV SCHEDULE.

6.PREMATURE STARTER CUTOUT.

7.COMBUSTION CHAMBER SHIFTED REARWARD ,C/O BOROSCOPE FOR MISALIGNED CC.

Q.LOW IDLE N2.

PRIMARY CAUSE OF SLOW ACC TIME HIGHER IN SECS FOR FACH % OF N2 BELOW NORMAL LIFE TRIM. EXCESSIVE IDLE TRIM SHIFT AS ABNORMAL ENGINE SENSITIVITY TO TRIM ADJUSTMENTS ARE INDICATIONS OF GAS PATH DISTRESS [HOT SECTION] OR FUEL CNTRL MALFUNCTION.

1.C/O TRIM RUN AND RESTORE IDLE RPM.

2.REPLACE FCU IF SNAG PERSISTS.

3.CHK 13TH STAGE BV STUCK IN OPEN POSITION.

4.C/O BOROSCOPIC INSP FOR CC DISTRESS [RISE IN F/F AND EGT AND DROP IN N2 RPM WILL INDICATE CC DISTRESS].

NOTE:- 36 CLICKS OF IDLE TRIM SCREW = 1 TURN.

10 CLICKS = 0.4 CHANGE IN EPR.

R.SLOW ACCELERATION.

1.LOW IDLE N2,RETRIM ENGINE.

2.BV OFF SCHEDULE [REF BLEED SYS TROUBLESHOOTING].

3.CC SHIFTED REARWARDS.C/O BOROSCOPIC INSP.

S.AUTO ACCELERATION. [PWR RISES WITHOUT THRUST LEVER MOVEMENT].

1.LOSS OF N2 SENSE TO FCU. REPLACE FUEL CONTROL UNIT.

T.EPR VARIES WITH ALTUITUDE.

1.OBSTRUCTED PT7 LINE TO EPR Tx.

2.LEAKING PT2 LINE TO EPR Tx.

3.DEFECTIVE START BLEED CONTROL VALVE. CHK BV OPEN

U.ENGINE FLAME OUT.

1.CHK CDP SENSE LINE TO FCU FOR HEAVY LEAKS, OBSTRUCTION, TOP UP SILICON OIL.

2.CHK FOR SHEARED FUEL PUMP DRIVE SHAFT BY CHKING FUEL DISCHARGE PRESSURE. [REF FUEL SYSTEM TROUBLE SHOOTING].

3.CHK CONCENTRICITY AND SQUARENESS OF FUEL PUMP DRIVE SHAFT. IF OVERLIMIT REPLACE G/B. [ENG O/H].

4.CHK OPN OF FSOV, AIRFRAME FUEL SYSTEM.

V.OFF IDLE SURGE[DURING ACC BELOW IDLE].

1.INSPECT ENGINE INLET AND EXHAUST AREAS FOR ANY DAMAGE DUE TO FOD.

2.BLEED VALVE OFF SCHEDULE,CHK PRBC VENT SCREEN [REF BLEED SYSTEM TROUBLESHOOTING].

3.P & D VALVE SETTING LOW,ADJUST IT OR REPLACE IT [CLOCKWISETO INCREASE].

4.GASPATH DETERIORATION,WATERWASH ENGINE.

5.CHANGE FCU.

6.IF SNAG PERSISTS,SEND ENGINE FOR INSPECTION.

W.HIGH PRESSURE SURGE.

1.CHK INLET OR EXHAUST AREAS FOR FOD.

2.CARRY OUT WATER WASH,IF NO DAMAGE FOUND,CHK FOR HIGH POWER SURGE DURINGGROUND RUN.

3.IF SNAG PERSISTS,SEND ENGINE FOR O/H FOR TURBINE AND EXHAUST SECTION DETAILED INSPECTION.

X.LOW FREQUENCY VIBRATION,CAUSED BY FUEL SYSTEM "RUMBLE" RUMBLE EXISTS WHEN BOTH CONDITIONS ARE MET :-

a.STEADY STATE ENGINE OPERATION.b.VIB FREQUENCY APPROX 10 HTZ.1.CHANGE P & D VALVE OR LOWER P & D VALVE SETTING [ANTICLOCKWISE TO DECREASE]. 2.CHANGE FUEL CONTROL UNIT.

Contents


 

MAINTENANCE TIPS

1.WHENEVER CLEARING MAIN AND NOSE WHEELS DURING CHK B, ENSURE THAT THEY CAN DO AT LEAST 10 LDGS. [TILL NEXT CHK B].

2.WHENEVER MAIN OR NOSE WHEEL REMOVED DUE TO ANY REASON. [WEAROUT, DEEP CUTS, SIDEWALL DAMAGE ETC]. ENSURE THAT THEY ARE DEFLATED AFTER REMOVAL.

3.IF APU DOES NOT START:-

A.CHECK BATTERY VOLTAGE

B.PUT APU START SWITCH TO START THEN ON AND CHK FOR DROP IN BATTERY VOLTAGE WHICH ENSURES STARTER CRANKING.

C.CHK FUEL SUPPLY TO APU.

USUALLY,THE PROBLEM CAN BE RECTIFIED BY CONNECTING GPU AND CHARGING THE BATTERY.[IF CHARGING RATE IS HIGH THEN BATTERY IS WEAK].ATTEMPT TO START APU AFTER BATTERY HAS ATTAINED 28 VDC.

4.IN CASE OF ANY INCIDENT,ACCIDENT,ON GROUNDOR IN FLIGHT REMOVE CVR AS WELL AS DFDR.

5.NOSE WHEEL SHUDDERING:-

A.CHK FOR TYRE PRESSURE ON BOTH NOSE WHEELS, IF DIFFERENT, EQUALISE TO CORRECT LEVEL ie 130 +0/-5 PSI.

B.CHK FOR CONDITION OF TORSION LINKS. IF ANY PLAY AT THE REAR END, IT MAY CAUSE NOSE WHEEL SHUDDERING.

6.IF AFTER PARKING/LANDING ONE OF THE MAIN WHEELS DEFLATES REMOVE THE MW + BRAKES OF CONCERNED AND ADJACENT WHEEL ALSO.

7.DURING MAINTENANCE, WITH AIRCRAFT ON GRD, USE ONLY ONE PACK TO PUT LESS LOAD ON APU.

8.DELETED.

9."ANTISKID INOP" LT REMAINS ON:-

THE PROBLEM MAY BE DUE TO:-

1.A/S CONTROL VALVES.

2.WHEEL TRANSDUCERS.

3.A/S CONTROL MODULE.

4.WIRING PROBLEM.

5.PROBLEM IN PARKING BRAKE CIRCUIT.

GO TO E&E COMPT TO SEGREGATE THE PROBLEM TO A PARTICULAR COMPONENT.IF L/G MODULE REPLACED CARRY OUT RETRATCTION CHECK.PUT ON HYD "B" PUMPS,OPEN GRD INTERCONNECT AND PARKING BRAKES ON,A/S INOP LT MAY GO OFF IF THE FAULT IS IN THE PARKING BRAKE CIRCUIT.

10.DURING CHK B INSPECTION CHK THE LOCKING OF THE TIE-BOLTS WHICH HOLDS [SUPPORTS] THE REAR OF THE CORE ENGINE.

11.FOR MOTORING OF ENGINES PULL OUT THE IGNITION CB.PUT START SW TO START POSN AND DO NOT MOVE THE START LEVER OUT OF ITS CUTOFF DETENT.

12.FOR EXCESSIVE CABIN PRESSURE LEAKAGE CHECK:-

A.CLOSE AUTOMATIC FLOW CONTROL VALVE.

B.MANUALLY [AC OR DC] CLOSE AFT OUTFLOW VALVE.

C.CHK FWD OUTFLOW VALVE GONE TO CLOSED POSITION.[BLUE LIGHT].

D.PRESSURISE THE CABIN,WITH APU TO DIFF PR OF 4 PSI.

E.NOTE THE TIME OF GRADUAL CABIN PRESSURE LEAK OUT.[SHOULD NOT TAKE LESS THAN 50 SECS FOR PRTO DROP FROM 4 PSID TO 2.5 PSID]. USUALLY THE PROBLEM AREAS ARE THE DOOR SEALS[CARGO AND ENTRY DOORS],OR SLIDING WINDOWS IN COCKPIT.

13.FUEL TRANSFER/DEFUELLING:-

FUEL TRANSFER FROM #2 TANK TO #1 TANK/CENTER TANK.

A.#2 BOOSTER PUMPS ON.

B.#2 ENGINE FUEL SOV OPEN [START LEVER TO IDLE].

C.MANUALLY POSITION DEFUELLING VALVE OPEN.

D.#1 FUELLING SOV OPEN/CENTER TANK FUELLING SOV OPEN. FUEL TRASFER FROM #1 TANK TO CENTER TANK /#2 TANK.

A.#1 TANJ BOOST PUMPS ON.

B.CROSSFEED VALVE OPEN.

C.#2 ENG FSOV OPEN.

D.DEFUELLING VALVE OPEN.

E.FUELLING SOV OF CENTER/#2 TANK OPEN.

14.IF PACK TRIPS DUE TO SUPPLY DUCT OVHT THEN "DUCT OVHT" AMBER LT WILL COME ON MUCH BEFOREE "PACK TRIP OFF" LT,CHANGE CTC OR MIX VALVE.

15.FUEL TRANSFER CAN BE DONE ONLY ON GRD BECAUSE DEFUELLING VALVE HAS TO BE MANUALLY POSITIONED TO OPEN.

16.WHILE CROSSFEEDING CAN BE DONE ANYTIME BY OPERATING CROSSFEED VALVE.

16.PACK NOISY:-

A.CHK WATER SEPARATOR COALESCER BAG CONDITION, REPLACE IF DIRTY.

B.CHK FOR PNEUMATIC LEAKS FROM WATER SEPRATOR, ACM, DUCT JOINTS AND MIX CHAMBERS.

C.35 DEGF SENSING FAULT SO 35øF CONTROL VALVE HUNTS CAUSING CABIN NOISE.

17.PACK TRIPS OFF:-

PRESS RESET BUTTON AFTER ALLOWING COOLING PERIOD. IF THE SNAG IS OF REPETATIVE NATURE, INVESTIGATE FURTHER.

PACK TRIP OFF OCCURS DUE TO :-

A.COMPRESSOR DISCHARGE OVHT --- 365øF.

B.TURBINE INLET OVHT --- 210øF.

C.SUPPLY DUCT OVHT --- 250øF.

PURGE VALVE LOGIC [PWR FROM TURBOFAN CB P6 PANEL]

A.AIRCRAFT ON GRD OR FLAPS NOT FULL UP.

B.PACKS SWITCH ON.

C.APU BLEED SW OFF.

PACK TRIP OFF MAY BE DUE:-

A.SENSOR PROBLEM.

B.GENUINE OVHT PROBLEM.

TO TROUBLESHOOT THE SNAG, OPEN ALL SENSORS, CLEAN THE PLUG AND REFIT. WITH SENSOR REMOVED, ATTEMPT TO OPERATE THE PACK. IF PACK DOES NOT OPERATE THEN IT IS A SENSOR PROBLEM. IF IT OPERATES, THEN PROBLEM IS DUE TO ACTUAL OVHT.

THE TEMPERATURE IN THE ABOVE MENTIONED THREE AREAS MAY RISE DUE TO :-

1.RAM AIR DOOR SYSTEM MALFUNCTION. CHK MODULATION PANEL [RAM AIR DOOR], EXIT LOUVERS, RAM AIR ACTUATOR OPN BY SIMULATING AIRCRAFT IN AIR CONDITION [L/G MODULE]. MODULATION PANELS SHOULD BE IN FULL OPEN POSITION ON GRD AND MODULATES TOWARDS CLOSED POSITION IN AIR.

2.CHK OPN OF TURBOFAN, TURBOFAN VALVE.

IF PACKS TRIP OFF DURING T/O :-

CHK CONDITION OF HEAT EXCHANGERS.

CHK RAM DOOR OPERATION.

TURBOFAN IS OPEN WHENEVER :-

A.AIRCRAFT ON GRD OR FLAPS NOT UP.

B.PACKS ON [PACK VALVE NOT CLOSED.

3.DIRTY OR CLOGGED HEATEXCHANGERS:-

IF CDT IS HIGH, PRIMARY H.E. INEFFICIENT.

IF TIT IS HIGH, SECONDARY H.E. IS INEFFICIENT.

IF SUPPLY DUCT OVHT THEN PROBLEM MAY LIE IN MIX VALVE. THEN CHK OPN OF MIX VALVE BY OPERATING PACKS AND CONTROLLING TEMPERATURE IN MANUAL MODE.

18.TAT/EPRL INDICATOR:-

TAT FLAG:- RESET CB, CHK PWR SUPPLY TO TAT PROBE. IF FLAG DOES NOT GO OFF. GRD THE AIRCRAFT.

EPRL FLAG:-RESET CB, SNAG CAN BE C/F UNDER MEL. PLACARD U/S AND INFORM PILOT.

19.IF LE FLAPS/SLATS TRANSIT LT REMAINS "ON" OR EXTEND/FULL EXTEND LT DOES NOT COME "ON",CHANGE THE PROXIMITY SWITCH.

20.MIST IN THE CABIN:-

WATER SEPRATOR CLOGGED,IT WILL ALSO CAUSE MIST IN PSUs IF SO CLEAN THE COASELANT BAG.

21.WATER DROPS IN FEW PSUs:-

GASPER CONNECTION AT BACK OF PSUs NOT PROPER. IF WATER DROPS FROM OVERHEAD DISTRIBUTION DUCT, THE DUCT HAS GOT SEPRATED. USE TEMPORARY REPAIRS [WITH TAPE]

TO RECTIFY THE SNAG:-

CHK FOR WATER SEPERATOR DRAIN GETTING CLOGGED.[USE LOCKING WIRE].

NOTE:-

A.PACK VALVE SOLENOID A AND TURBOFAN SOV HAVE MANUAL OVERRIDE.

B.35 DEGF CONTROL VALVE OPENS WHEN 35 DEGF SENSOR PLUG IS REMOVED.

C.140 DEGF DUCT LIMIT SENSOR MODULATES MIX VALVE, THEN THE TEMP REGULATOR TO FULL COLD POSITION.

D.190 DEGF BYPASSES TEMP REGULATOR AND MOVES MIX VALVE TO FULL COLD POSITION.

E.WITH TEMP SELECTED IN AUTO IF DUCT OVHT COMES ON THEN MIX VALVE GOES TO FULL COLD POSITION BYPASSING THE TEMP REGULATOR. WAIT FOR SOMETIME THEN PRESS TRIP RESET. AGAIN IF DUCT OVHT COMES ON THE TEMP REGULATOR IS FAULTY. S/W OVER TO MANUAL MODE.

22.CABIN STARTS CLIMBING DURING DESCENT:-

A.CHK WEATHER FWD OUTFLOW VALVE CLOSED LT, COMES ON OR NOT. IF COMES ON PRESSURISATION SYSTEM IS OK.

B.C/O PRESSURISATION LEAK CHECK TO LOOK FOR LEAKS.

C.IF NO LEAK IS OBSERVED, DO A PACK COOLING PERFORMANCE TEST.

D.IF THAT IS ALSO OK, AIR BLEED TO PACK MAY BE SUSPECT.

CHK DUCT PRESSURE.

CHK 450øF THERMOSTAT FOR LEAKS.

CHK LINE FROM 450øF THERMOSTAT TO DIFF PR REGULATOR FOR LEAKS, IN CASE OF LEAK, MSOV WILL REMAIN CLOSED, WHEN IT SHOULD HAVE BEEN OPEN WITH THROTTLES RETARDED.

FOR PRESSURISATION ELECTRICAL CHECK REFER MAINTENANCE MANUAL.

23.PRESSURISATION LEAK FROM FWD/AFT ENTRY DOORS:-

A.CHECK SEAL CONDITION, CHK CLEARANCE BETWEEN DOOR AND SILL, CHK AND LOWER FLAPS, CHK DOOR HINGE FLAPS FOR DAMAGE.

24.PRESSURISATION FAILURE:-

A.C/O PRESSURISATION ELECTRICAL CHK,IF OK,PRESSURISATION SYSTEM IS OK.

B.C/O LEAK CHK OF ALL DOORS AND WINDOWS [FWD/AFT ENTRY AND SERVICE DOORS,FWD AND AFT CARGO DOORS,E&E COMPT DOOR,COCKPIT SLIDING WINDOWS OK].

C.ESPECIALLY CHK RUBBER HOSES/DUCTS JOINING HOT AND COLD DUCTS OF AIR COND BAY TO MIXING CHAMBERS.THESE ARE LOCATED AT FWD WALL OF AIR COND BAY. ATTN SHOULD BE GIVEN TO JOINTS WHERE AIR COND DUCTS PASS FROM UNPRESSURISED AREA TO PRESSURISED AREA.

25."AUTO FAIL" LT:-

A.POWER LOSS>15 SECS.

B.CABIN PRESSURE CHANGE > 1800 FT/MIN OR 1 PSI/MIN.

C.CABIN ALTITUDE EXCESS OF 13875 FT.

26.AUTO MODE:-

MAX CABIN ASCENT RATE 500 FT/MIN.

MAX CABIN DESCENT RATE 350 FT/MIN.

27.AUTOMATIC FLOW CONTROL VALVE.[E&E COMPT] CLOSES AT 2.0 TO 2.8 PSID.

DISTRIBUTION RELIEF VALVE OPENS :- 17" TO 27" OF WATER ABOVE CABIN PRESSURE.

28."OFF SCHEDULE DESCENT":-

AIRCRAFT HAS NOT REACHED WITHIN 0.25 PSI OF FLT ALT SELECTED AND GOES OFF WHEN AIRCRAFT ASCENDS AGAIN. WARNING CKT DISARMED ONCE AIRCRAFT IS WITHIN 0.25 PSIA OF SET FLT ALT AND CKT WILL NOT BECOME ACTIVE UNTIL AFTER AIRCRAFT LANDS AND GOES OUT AT TOUCHDOWN.

29.IF CABIN ALT SHOULD EXCEED 14,625 FT,A SEPRATE CKT IN CONTROLLER DRIVES OUTFLOW VALVE TO FULL CLOSE POSITION.

30.TURBOFAN SOV REMAINS OPEN WITH PACK S/W OFF.

SOL A STUCK ENERGISED,BUTTERFLY STUCK OPEN,CLOSE S/W FAULTY,CHANGE PACK VALVE.

31.FWD OUTFLOW VALVE OPEN:-

OPEN WHEN AFT OUTFLOW VALVE IS 3d eg FROM CLOSED.

CLOSES WHEN AFT OUTFLOW VALVE IS 1 deg FROM CLOSE.

PRESSURISATION SYSTEM TEST.

1.AUTOMATIC MODE TEST

A.PLACE MODE SELECTOR TO AUTO,CHK AUTO FAIL,STANDBY AND OFF SCHEDULE DESCENT AND MANUAL LTS ARE OFF.

B.PLACE FLT-GRD SW TO FLT POSITION,AND CHK OUTFLOW VALVE GOES TO FULL CLOSED POSITION,ON VALVE POSN INDICATOR[WITHIN 30 SECS].PLACE FLT-GRD S/W TO GRD AND VERIFY OUTFLOW VALVE GOES TO FULL OPEN POSN.

C.NOW PLACE MODE SELECTOR S/W TO CHECK POSN AND FLT-GRD S/W TO FLT POSN. VERIFY THAT AUTO FAIL AND STBY LTS COME ON.

D.[WITH MODE SELECTOR IN AUTO] CHK AUTO MODE BAROMETRIC CORRECTION CKT.

FLT ALT--- 35,000 FT

LAND ALT--- FIELD ALT

FT-GRD S/W--- FLT

WAIT TILL OUTFLOW VALVE GOES TO CLOSE POSITION.

a]SET CAPTS ALTIMETER TO FIELD PRESSURE.

b]OPEN L/G LT CB AND CHK OUTFLOW VALVE GOES TO FULL OPEN POSITION.

c]SET CAPTS ALTIMETER TO 0.3" OF Hg ABOVE FIELD PRESSURE AND CHK OUTFLOW VALVE GOES TO FULL CLOSED.

d]SET CAPTS ALTIMETER TO 0.3" Hg BELOW FIELD PRESSURE AND CHK OUTFLOW VALVE GOES TO FULL OPEN.

2.STANDBY MODE TEST:-

A.CAB ALT TO FIELD ALTITUDE.

CAB RATE TO PIP MARK.

SET BAROMETRIC CORRECTION ON ALTIMETER 2.

SW MODE SELECTOR TO STBY AND CHK.STANDBY LT COMES ON.

CAB ALT TO 200 FT BELOW FIELD ALT

FLT-GRD SW TO GRD POSN AND CHK OUTFLOW VALVE IS OPEN.

B.OPEN L/G LT CB AND CHK OFV GOES TO FULL CLOSED POSN.

PLACE FLT-GRD SW TO FLT

CLOSE L/G LT CB AND CHK OFV REMAINS CLOSED.

IN CASE CAB ALT SETTING TO 200 FT ABOVE FIELD ALT AND CHK OFV GOES TO

FULL OPEN POSITION.

C.CHK AIRCRAFT BAROMETRIC CORRECTION.

CAB ALT--- FIELD ALTITUDE

F/O ALTIMETER--- 0.3 " Hg ABOVE FIELD PRESSURE AND CHK OUTFLOW VALVE GOES TO CLOSE POSN.

WITH F/O ALTIMETER 0.3' OF Hg BELOW THE CORR VALVE.CHK OFV GOES TO OPN POSITION.

IF CABIN KEEPS ON CLIMBING IN AUTO MODE:-

AND ELEC CHK IN AUTO MODE FOUND OK.THE PROBLEMS MAY BE DUE TO AIR GRD SENSOR NOT CHANGING TO AIR MODE AFTER T/O.

SIMULATE AIR MODE BY OPENING L/G LT CB OR BY PRESSING AIR S/Ws ON L/G MODULE IN E & E COMPT.

L/G MODULE OK---IF ALL OTHER SYSTEM LIKE,TURBOFAN,STALL WARN ETC WORKING OK.

IF OFV STILL DOES NOT GO TO CLOSE POSN,CHANGE L/G MODULE.

IF L/G MODULE IS ON,THEN REPLACE CPC [CABIN PRESSURISATION CONTROL] ON P5,[FAULT WITHIN AUTO MODE CONTROL CARD].

HIGH PITCHED HUMMING NOISE FROM AREA ABOVE CEILING PANELS, ATTN SHOULD BE PAID TOWARDS THE DUCTS GETTING DISBONDED AND RECTIFIED ACCORDINGLY BY REPAIRING/REPLACING DISTRIBUTION DUCTS.

SMOKE/BURNING SMELL REPORTED IN CABIN/COCKPIT:-

1.WHENEVER THE ABOVE SNAG IS REPORTED, EXAMINE LEFT AND RIGHT AIR COND WATER SEPRATOR DRAIN IN A GLASS FOR PRESENCE OF OIL.

2.IF OIL NOTICED,ISOLATE THE SAME ,CHK ENG/APU BLEED VALVE OF RELEVANT PACK AND SEE IF OIL TRACES EVIDENCE ARE PRESENT THERE.

3.IF OIL NOT TRACED TO APU/ENG BLEED VALVE, REPLACE ACM AS PRECAUTIONARY MEASURE. ALSO REPLACE HEAT EXCHANGERS CLEAN AIR COND H.E. DUCTING TO REMOVE ANY TRACES OF OIL.

4.CHK FOR HYD FLUID LEAKAGE FROM LANDING GEAR DOWN LINE PASSING THRU THE EXCHANGER DUCT [T/R LINE].

5.C/O PACK COOLING PERFORMANCE CHK. WATER SEPRATOR 35øF CONTROL SYSTEM:- KEEPS WATER SEPRATOR TEMPERATURE ABOVE FREEZING TO PREVENT ICE FORMATION. BITE CHK ON 35øF CONTROL UNIT TO CHK SERVICEABILITY OF 35øF VALVE, SENSOR AND CONTROL.

TEST INSTRUCTION:-

A.PACK S/W OFF.

B.ROTATE TEST S/W TO EACH TEST POSN AND WAIT FOR STEADY LT. POSN GO [GREEN] NO GO [RED]

1. --- REPLACE 35øF CTRL VALVE.

2. VERIFY 35øF VALVE OPEN, REPLACE 35øF CTRL VALVE. IF NOT REPLACE VALVE.

3. --- REPLACE 35øF CTRL VALVE.

4. VERIFY 35øF VALVE CLOSED. REPLACE 35øF CTRL VALVE.

5. --- REPLACE 35øF SENSOR.

TEMPERATURE CONTROL SYSTEM:-

INPUTS TO TEMP REGULATOR:-

1.DUCT ANTICIPATOR SENSOR.

2.DUCT LIMIT SENSOR [140øF] [MIX VALVE GOES TO FULL CLOSED].

3.TEMP SELECTOR.

4.CABIN TEMP SENSOR.

OUTPUTS FROM TEMP REGULATOR:-

1.MIX VALVE.

SENSORS AND FUNCTIONS:-

1.DUCT LIMIT SENSOR [140øF] DRIVES MIX VALVE TO COLD POSN.

2.DUCT OVHT S/W [190øF] DUCT OVHT AMBER LT COMES ON.

3.DUCT OVHT S/W [250øF] PACK TRIP LT ON.

4.ANTICIPATOR SENSOR, ANTICIPATES RISE IN TEMPERTURE.

BITE CHECK ON CABIN TEMP CONTROLLER [E3-1].

CHKS SERVICEABILITY OF CONTROL UNIT [CTC], CABIN SENSOR, ANTICAPATOR SENSOR, DUCT LIMIT SENSOR, TEMP SELECTOR.[P5].

FOR TESTING:-

PUT ENG AND APU BLEED SWITCH OFF, OPEN AIR COND OVHT CB ON P6,PUT LH AND RH PACK SW ON, OPT TEMP SELECTOR IN MANUAL MODE [CHK MIX VALVE OK], SET TEMP SELECTOR IN MODULE OF AUTOMODE. ROTATE TEST SWITCH ON MODULE. ON SELECTION OF PACK, THE DUCT TEMPERATURE KEEPS ON RISING, WITH MIX VALVE

OPERATION NORMAL:-

FAULT LIES IN 35øF CONTROL SYSTEM,35øF CNTRL VALVE STUCK OPEN.35øF CONTROLLER FAULTY.35øF SENSOR FAULTY.[CARRY OUT BITE CHK TO TROUBLESHOOT THE SNAG].

Contents


 

APU TROUBLESHOOTING

APU TROUBLESHOOTING MAY BE DIVIDED INTO FOUR CATEGORIES:-

1.MALFUNCTION BEFORE START.

2.MALFUNCTION AFTER START.

3.MALFUNCTION DURING START.

4.MALFUNCTION RELATED TO APU SHUTDOWN.

 

LOW OIL PRESSURE AUTO SHUTDOWN:-

1.CHK OIL LEVEL.

2.CHK OIL FILTER. IF EXCESS METAL PARTICLES, REPLACE APU.

3.START APU AND MONITOR OIL PRESSURE.

4.IF < 50 PSI, CHK OIL PUMP PRESSURE RELIEF VALVE SETTING. IF OIL PUMP PR RELIEF SETTING OK, THEN REPLACE OIL PUMP. IF QUILL SHAFT BROKEN REPLACE APU.

5.IF > 50 PSI, REPLACE LOP S/W,IF PROBLEM PERSISTS REPLACE APU MODULE.

6.PROBLEM PERSISTS REPLACE APU. TO CHK OIL PUMP DRIVE, OIL PUMP REAR BLANKING DRIVE COVER TO BE OPENED AND SQUARE DRIVE TO BE ROTATED WITH SUITABLE TOOL, IF IT IS COMPLETELY FREE, GIVING A FEEL THAT QUILL SHAFT IS BROKEN. CHANGE APU.

LOP AMBER LT COMES ON WHENEVER OIL PR < 45+/- 3 PSI

HOT AMBER LT ON P5 PANEL COMES ON WHEN APU OIL TEMP EXCEEDS 250+/-10øF

OR 285+/-10øF.

HOT AUTO SHUTDOWN.

1.CHK ACC COOLING AIR SOV FOR FULL OPEN. LOOSE OR DISCONNECTED, OR CRACKED PNEUMATIC LINE TO COOLING AIR SOV. [PNEUMATIC ACTUATOR].

2.CHK COOLING AIR FAN SCREEN FOR BLOCKAGE, CHK FOR OPN OF COOLING AIR FAN, CLEAN SCREEN WITH VACUUM CLEANER, TO CHK OPN OF COOLING AIR FAN PLACE HAND AT EXIT OF OIL COOLER WITH APU OPERATING. IF COOLING FAN U/S THEN REPLACE APU.

3.CHK OIL QTY AND OIL FILTER CONDITION.

4.DISCONNECT OIL TEMP SW PLUG AND START ENGINE. CHK OPN OF ACC COOLING VALVE. IF ENG DOES NOT START WITH HOT SW DISCONNECTED, REPLACE APU PANEL P5-5.

5.CHK AIRFLOW FROM OIL COOLER.

6.CHK FUEL HEATER OPN. [OPN AT 60øF, FULL OPEN AT 135øF].

7.IF SNAG STILL PERSISTS CHANGE OIL TEMP SW.

8.REPLACE APU.

OVERSPEED AUTOSHUTDOWN:-

1.PUT MASTER SW OFF, PRESS O/S RESET SW ON M280 MODULE TO EXTINGUISH OVERSPEED LT.

2.CRANK APU, LISTEN FOR NOISE/VIBRATION. CHK OIL IN EXHAUST.

3.START APU, IF IT IS O/S THEN REPLACE FUEL CONTROL UNIT.

4.IF PROBLEM PERSISTS REPLACE 3 SPEED SWITCH [CENTRIFUGAL SW].

5.IF APU O/S LT PROBLEM STILL PERSISTS OR APU GIVES ABNORMAL NOISE/VIBRATION. REPLACE APU.

IF OK LT COMES ON WHEN APU IS SHUTDOWN,BY TURNING MASTER SWITCH OFF [NORMAL SHUTDOWN]:-

THIS INDICATES MALFUNCTION.

OVERSPEED AUTO PROTECTION SYSTEM.

CHK PNEUMATIC SOLENOID OR 3 SPEED SWITCH.

IF APU AUTOSHUTDOWN DUE TO OVERSPEED.

RESET O/S LT. BY O/S SW ON, APU MODULE IN E & E COMPT.

MAY BE CAUSED BY ERRATIC GOVERNOR OPN IN APU FUEL CONTROL UNIT OR BY DEFECTIVE 3 SPEED SWITCH.

WHEN OPN OF O/S LT. OCCURS AS A RESULT OF UNSUCESSFUL APU START,A TIME LT OF 2 MINUTES SHOULD ELAPSE BEFORE ATTEMPTING ANOTHER START. THE O/S LT SHOULD GO OUT DURING SUBSEQUENT START CYCLE.

APU AUTOSHUTDOWN DUE OVERSPEED ACTION:-

1.SELECT APU MASTER S/W TO OFF.

2.PRESS OVERSPEED RESET S/W ON APU MODULE IN E & E COMPT TO EXTINGUISH O/S LT.

3.START APU,IF APU STARTS AND O/S THEN REPLACE FCU OR 3 SPEED SWITCH. IF APU VIBRATES EXCESSIVELY OR GIVES UNUSUAL NOISES, SHUTDOWN AND REPLACE THE APU. IF NO INDICATION OF VIB/NOISE CONTINUE APU IN SERVICE.

IF APU NOT STARTING, THE PROBLEM MAY BE DUE:-

1.BATTERY NOT CHARGED FULLY.

2.FUEL NOT REACHING C.C.

3.NO IGNITION. SO, CONNECT A GROUND POWER UNIT [GPU] AND CHANGE THE AIRCRAFT BATTERY. IF BATTERY OK, PULL THE APU IGNITION CB, REMOVE THE FUEL NOZZLE FROM CC, AND CRANK APU BY PUTTING APU MASTER SWITCH TO START POSITION. OBSERVE FOR FUEL SPRAY FROM THE NOZZLE. IF FUEL FLOW OK, PULL FUEL CB OUT, OR BY REMOVING FUEL SOLENOID CANNON PLUG ON APU. CRANK APU, LISTEN TO CLICKING OF IGNITER PLUG.

IN CASE OF HOT SHUTDOWN:-

START APU AGAIN, AND OBSERVE COOLING AIRFLOW BY PUTTING HAND ON THE AIR EXIT FROM OIL COOLER. THIS WILL RECTIFY THE OPN OF COOLING AIR SOV, COOLING AIR FAN, PNEUMATIC ACTUATOR ETC. IF NO AIRFLOW AT EXIT OF OIL COOLER, CHK INDIVIDUAL COMPONENTS.

START SEQUENCE:-

1.BATTERY SWITCH ON.

2.APU MASTER SW TO START.

3.APUI SW TO ON.

4.APU FUEL SOV + AIR INLET DOOR FULLY OPEN.

5.STARTER MOTOR ENERGIZES.

6.10% RPM,LOP1 CLOSES AT 45ñ5 PSI, IGN SYS ENERGIZES, FUEL SOLENOID OPENS.

7.35% RPM,35% SPEED SW OPENS [OLD A/CS], STARTER DISENGAGES [OR 60 SECS CUTOUT]. 8.37%LOP2 OPEN AT 55 PSI,OIL PR LOP AMBER LT GOES OFF.

9.50% RPM,50% SW OPENS [ON NEWER A/CS], STARTER DISENGAGES.

10.95% RPM,95% SWITCH ENERGIZES, APU GEN OFF BUS LT ON, APU BLEED SW ARMED, IGNITION OFF,3 WAY PNEUMATIC SOLENOID VALVE ENERGIZED, LOP AUTOSHUTDOWN ARMED.

11.100% RPM, SPEED 42000 RPM, NORMAL RUNNING.

LOP 2:- CLOSES AT 45 PSI, RESULTS IN LOP AUTOSHUTDOWN.

HOT:- OPENS AT 140ñ6 DEGC RESULTS IN HOT AUTOSHUTDOWN.

OVERSPEED:- 110% SW RESULTS IN O/S AUTOSHUTDOWN.

IF SURGE BLEED VALVE OPEN ON GRD, REMOVE ELECT CONN, TAP BLEED VALVE, REMOVE AND MANUAL CLOSE THE VALVE FOR ENGINE START ADVISE PILOT TO SHUT OFF APU AFTER TAKE OFF.

APU SHUTDOWN:-

NORMAL:-

1.APU MASTER SW TO OFF POSN CLOSES #1 TANK FSOV, AIR INLET DOOR AND PRODUCES SIMULATED 110 % OVERSPEED, DE-ENERGIZING THE FUEL SOLENOID VALVE.

EMERGENCY:-

1.PULLING EITHER APU FIRE HANDLE CLOSES APU FSOV, FUEL SOLENOID VALVE AND AIR INLET DOOR.

AUTO:-

1.OVERSPEED 110%.2.LOP 45 PSIG.3.HOT 140ñ6øC [285ñ10øF].4.APU FIRE DETECTION.

5.TURNING THE BATTERY SW TO OFF ON GRD.

ALL AUTOSHUTDOWNS CLOSE THE FUEL SOLENOID VALVE.

GENERAL SPECIFICATIONS:-

GTCP85-129.

FUEL FLOW --- 250 lbs/hr.

RATED SPEED --- 41,430 RPM.

OUTPUT SPEED AT GEN DRIVE --- 6000 RPM.

EGT SUSTAINED MAXIMUM --- 600 TO 620øC.

TRANSIENT --- 760øC

OIL TEMP [MAX] --- 140+/-6øC

--- 285+/-10øF.

ALTITUDE LIMITATIONS:-

SEA LEVEL TO 10,000 FT --- BOTH ELECTRICAL + PNEUMATIC LOADS.

10,000 FT TO 17,000 FT --- EITHER ELECTRICAL OR PNEUMATIC LOADS.

17,000 FT TO 25,000 FT --- ONLY ELECTRICAL LOADS.

APU OIL CAPACITY:- 5-1/2 QUARTS [1« GALLON].

LOW OIL QTY:-1-1/2 QTS.

OIL CONSUMPTION:-113 KGS/HR.

SPEED SW:-

35% OR 50% :- STARTER CUTOUT.

95% :- APU READY TO LOAD.

110% :- OVERSPEED AUTOSHUTDOWN.

APU CONTROL THERMOSTAT:-

WORKS AS ACCELERATION CONTROL THERMOSTAT, WHEN APU ACCELERATES TO 95% RPM. F/F CONTROLLED TO KEEP EGT WITHIN LIMITS.

LOAD CONTROL THERMOSTAT:- OVER 95% RPM CONTROLS BLEED TAKEN FROM APU TO ACCOMMODATE EGT WITHIN LIMITS.

FUEL SOL VALVE +IGN SYS DOES NOT ENERGIZE, SHORT #3 AND# 4 PINS OF LOP1 CANNON PLUG [SEQUENCING SWITCH].

APU NOT STARTING:-

1.CHK BATTERY VOLTAGE, CONNECT GPU, CHARGE BATTERY.

2.MOVE APU MASTER SW TO START.

3.CHK APU FUEL SOV OPENS.

4.CHK APU INLET DOOR OPENS.

5.CHK STARTER MOTOR ENERGIZES [DROP IN BATTERY VOLTAGE].

6.CHK FUEL SOLENOID VALVE OPENS AND IGNITION SYSTEM OPERATES [BOTH ARE INITIATED BY LOP1 S/W, SHORT PINS 3 & 4 IN LOP1 SW AND ATTEMPT START AGAIN].

7.IF ANY OF THESE TWO OPERATIONS ie EITHER FUEL SOLENOID VALVE OPENS OR IGNITION PLUGS FIRES THEN THE FAULT LIES IN THE OTHER ONE.

SURGE BLEED VALVE:- OPERATES ONLY WHEN RPM > 95% AND AIRCRAFT IN AIR PREVENTS SURGING. ON GRD IT REMAINS CLOSED. TO CHK SURGE BLEED VALVE OPN ON GRD, OPEN LDG LT CB AND CHK AIRFLOW FROM COOLING AIR PORT RISES + EGT RISES +NOISE RISES.

NOTE:-

SOMETIMES AIR INLET DOOR OPENS, BUT STARTER DOES NOT ENGAGE THE MICRO-SWITCH IN AIR INLET DOOR DOES NOT GET DEPRESSED THUS NO FURTHER SEQUENCING POSSIBLE. FOR THIS, WHILE STARTING APU, ASK TECH TO PUSH THE AIR INLET DOOR BY HAND TO ACTUATE THE MICRO-SWITCH.

BOTH ENGINES SLOW STARTING:-

THE TROUBLE MAY BE DUE TO APU NOT BEING ABLE TO TAKE BLEED LOADS.

1.START APU, PUT BLEED LOAD BY OPERATING ONE OF THE PACKS. NOTE APU EGT AND APU GEN FREQUENCY.

2.PUT ON SYSTEM B PUMPS. NOTE APU EEGT [MUST BE AROUND 600 TO 620øC] AND APU GEN FREQUENCY [400 CPS].

IF APU EGT IS LESS THAN ABOVE SAID AND GEN FREQUENCY IS MORE THAN 400 CPS. APU LOAD THERMOSTAT MAY BE ADJUSTED SO AS TO GET MORE BLEED FROM APU.

1 VERNIER SCALE CLOCKWISE ROTATION = 2 DEG RISE IN APU EGT.

ALSO IF APU GEN FRQ DROPS HEAVILY ON PUTTING BLEED LOAD THEN THE APU LOAD THERMOSTAT SHOULD BE TURNED DOWN [TO GET LESS LOAD ON APU]. IF SNAG CANNOT BE RECTIFIED, CHANGE FCU. INSPECT FUEL FILTER FOR CONTAMINATION.

BOTH ENGINES SLOW STARTING SNAG, MAY ALSO BE DUE TO HEAVY LEAKS IN APU BLEED LINES.

APU MAY REFUSE TO START AFTER PROLONGED GROUNDING DUE TO LACK OF:-

1.FUEL IN APU FEED LINE.

2.LIMITED CAPACITY OF APU FUEL PUMP TO SUCK FUEL FROM AIRCRAFT TANK.

IF INLET DOOR AND APU FSOV OPEN, STARTER NOT CRANKING AND CCB POPS OUT:- 35% OR 50% [DEPENDING ON A/C] CENTRIFUGAL SW SHORT CIRCUITED.

APU CANNOT BE STARTED AFTER PROLONGED GROUNDING IN ABSENCE OF 115V AC GPU, BOOSTER PUMPS CANNOT BE SWITCHED ON 28V DC CART CAN BE USED.

1.CONNECT FUEL BOWSER TO REFUEL POINT, CHK FUEL PR OF BOWSER DOES NOT EXCEED 25 PSI.

2.OPEN DEFUELLING VALVE.

3.OPEN #2 ENGINE FUEL SOV.

4.OPEN CROSSFEED VALVE.

5.USING 28V DC EXT POWER, START APU.

APU STARTS NORMALLY BUT LOP AUTOSHUTDOWN JUST AFTER APU GEN OFF BUS LT ILLUMINATES:-

1.CHK OIL QTY.

2.CHANGE LOP2 SWITCH.

3.IF SNAG STILL PERSISTS, CHK OILM FILTER FOR CONTAMINATION, IF SNAG PERSISTS REPLACE APU ACC MODULE [E3-3 RACK].

APU STARTER MOTOR DUTY CYCLE:-

1 MINUTE ON,4 MINUTES OFF.

FOR MAX OF FOUR ATTEMPTS, WHICH CAN BE REPEATED AFTER 30 MINUTES COOLING PERIOD.

1ST--->2ND--->5MINS--->3RD--->60 MINS.

LOAD CONTROL THERMOSTAT ADJUSTMENT:-

VARIOUS REASONS FOR PREMATURE REMOVAL OF LOAD CONTROL THERMOSTAT ARE:-

1.APU HUNTING.

2.APU NOT TAKING LOAD.

3.APU EGT SHOOTS UP WITHOUT LOAD.

4.NOT RESPONDING TO EGT ADJUSTMENT.

5.AFTER PUTTING ALL LOADS,EGT GOES TO 730 DEGC.

ADJUSTMENT:-

WITH APU RUNNING ON LOAD AND CONSTANT MONITORING OF EGT IN COCKPIT,MOVE THE ADJUSTMENT NUTOF THE THERMOSTAT IN ANTICLOCKWISE DIRECTION TO LOWER EGT.[MORE LOAD CAN BE PUT ON EGT].AND IN CLOCKWISE DIRECTION RAISE EGT. ANY TENDENCY OF APU EGT TO EXCEED 650øC CAN BE ADJUSTED BY PUTTING APU BLEEED SW TO OFF POSITION. RECHECK EGT WITH APU ON LOAD AFTER ADJUSTMENT.

UNCONTAINED APU FIRE:-

DUE TO BLOCKED SHROUD DRAIN AND PLENUM FUEL DRAIN, MAY RESULT IN DAMAGE TO ADJOINING TE FLT CONTROL SURFACES.

APU CHK AFTER OVER TEMP DURING START:-

DURING START ACCELERATION IF EGT EXCEEDS 760øC,CHK THE FOLLOWING TO PREVENT REOCCURANCE.

BAT SW OFF, APU START SW OFF, OPEN CB ON APU MODULE E3-2,OPEN APU SHROUD.

1.REMOVE COMBUSTION UNIT.

2.VISUALLY EXAMINE HOT SECTION FOR DISTRESS.

2A.TURBINE WHEEL TIP FOR EROSION, BURNING.

2B.TURBINE WHEEL BLADES FOR CORROSION, RUBBING.

2C.NOZZLE GUIDE VANES AND TORUS FOR EROSION.

IF ANY EVIDENCE OF DISTRESS, REMOVE APU OTHERWISE C/O FOLLOWING STEPS AND RETURN APU TO SERVICE.

3A.REPLACE COMBUSTION UNIT.

3B.REPLACE FUEL CONTROL UNIT.

3C.REPLACE CONTROL THERMOSTAT.

3D.CHK FUEL DRAINS FOR CLOGGING.

3E.CHK BATTERY VOLTAGE.

3F.CLLOSE CB ON APU MODULE E3-3.

3G.START APU AND OBSERVE EGT WITHIN LIMITS.

ENGINE TROUBLESHOOTING:-

I.LUBRICATION SYSTEM:-

A.LOW OIL PRESSURE.

1.LOW OIL QTY.

2.DEFECTIVE INDICATING SYSTEM.

3.DEFECTIVE OIL PR RELIEF VALVE.

4.DEFECTIVE MAIN OIL PUMP.

B.HIGH OIL PRESSURE.

1.DEFECTIVE INDICATION SYSTEM.

2.DEFECTTIVE OIL PRESSURE RELIEF VALVE.

3.OBSTRUCTED OIL PRESSURE SENSE TO PRESSURE RELIEF VALVE.

4.HIGH BREATHER PRESSURE.

C.OIL PRESSURE FOLLING THROTTLE:-

1.DEFECTIVE OIL PRESSURE RELIEF VALVE.

D.OIL STRAINER DIFF PR SIGNAL DOES NOT GO OUT:-

1.DEFECTIVE INDICATION SYSTEM.

2.CLOGGED MAIN OIL STRAINER.

E.HIGH OIL TEMP:-

1.LOW OIL QTY.

2.DEFECTIVE INDICATING SYSTEM.

3.FUEL DEICING VALVE STUCK OPEN.

4.FUEL/OIL COOLER BYPASS VALVE OPEN.

5.HOT AIR LEAKAGE INTO #4 & #5 BEARING COMPARTMENT.

6.OIL SYSTEM CONTAMINATION.

F.EXCESSIVE OIL CONSUMPTION:-

1.EXTERNAL TUBING LEAKAGE.

2.OIL DISCHARGE AT OVERBOARD BREATHER.

3.OIL WETTING IN GAS PATH.

4.OIL LEAKAGE AT GEARBOX.

II.BLEED SYSTEM

A.BLEED OFF SCHEDULE.

1.PRBC VENT SCREEN CONTAMINATION.

2.DEFECTIVE PT2,PS3,OR PS4 TUBES.

3.PS3 CONTAMINATION.

4.PS4/BLEED VALVE DEFECT.

5.DEFECTIVE PRBC.

6.DEFECTIVE START BLEED CONTROL VALVE [SB 5425].

7.DEFECTIVE START BLEED VALVES.

TO AVOID POSSIBILITY OF UNCONTAINED APU FIRE DUE TO BLOCKED SHROUD AND FUEL DRAIN:-

1.OPT APU AT NO LOAD IDLE FOR 1 MINUTE PRIOR TO SHUTDOWN.

2.OBS STARTER DUTY CYCLE,1 MT ON,4 MINS OFF.

SERVICEABILITY TEST FOR FUEL HEATER:-

CHK FUEL TEMP ON THE GAGE ON P5PANEL.IF > 64øF [18øC],CHK THERE IS NO AIRFLOW THRU THE HEATER EXIT. IF < 64 DEGF, AIRFLOW SHOULD BE THRU HEATER EXIT PORT.

SERVICEABILITY OF SURGE BLEED VALVE:-

WITH APU OPERATING, OPEN L/G LTS CB ON P6 PANEL, SURGE BLEED VALVE WILL OPEN CAUSING INCREASED AIRFLOW THRU COOLING AIRFLOW EXHAUST PORT WITH INCREASED NOISE LEVEL.

SERVICEABILITY OF FCU:-

WITH APU OPERATING, CHK APU GEN FREQ, PUT ISOLATION VALVE OPEN, PUT BOTH PACKS ON, NOTE DROP IN APU GEN FREQUENCY, IF DROP > 12 HTZ, REPLACE FCU.

SERVICEABILITY OF COOLING AIR SOV:-

REMOVE PR LINE FROM PNEUMATIC ACTUATOR AND ATTACH A HOSE, APPLY 7 TO 8 PSI PR, COOLING AIR SOV SHOULD OPEN.

SERVICEABILITY OF AIR INLET DOOR:-

SHOULD OPEN WITHIN 20 SECS. IF NOT, REMOVE ELECTRICAL CONNECTION TO INLET DOOR ACTUATOR. OPT INLET DOOR BY PULLING [PUSHING],AT ACTUATOR ARMS.CHK FOR BINDINGS.

TWO ADJUSTMENTS ON DOOR ACTUATOR TO INCREASE/DECREASE STROKE:-

C.W. :- FOR DOOR IN OPEN POSITION.

C.C.W:- FOR DOOR IN CLOSED POSITION.

ADJUSTMENT ON B.V.[APU]:-

OPENING RATE,TO INCREASE OPENING TIME ,ROTATE CLOCKWISE.

OIL FUMES IN APU BLEED AIR:-

CHK FOR PLUGGED OIL TANK VENT AT EXHAUST FLANGE.

APU CONTROL MODULE CB POPPING OUT:-

THIS IS A SHORT CIRCUIT PROBLEM, THE POINT AT WHICH CB POPS OUT IN START SEQUENCE IS AN INDICATION AS TO WHICH COMPONENT HAS SHORTED.

CB POPS BEFORE STARTER MOTOR ENGAGES:-

1.CHK FOR SHORT CKT IN APU FSOV, INLET DOOR ACTUATOR OR STARTER LEADS.

CB OPENS AFTER STARTER MOTOR ENGAGES:-

1.CHK FOR SHORT CKT IN 35%,95%,110% CENTRIFUGAL SW.

2.LOP1 SW.

3.FUEL SOLENOID VALVE.

4.IGNITION UNIT, IGNITION LEADS.

5.APU WIRE HARNESS.

6.CHANGE APU CNTRL MODULE.

IF CB OPENS JUST BEFORE APU REACHES 95% RPM:-

CHK FOR SHORT CKTIN CENTRIFUGAL SW,3 WAY PNEUMATIC SOLENOID VALVE [WHICH CHANGES CONTROL THERMOSTAT FROM ACCELERATION MODE TO LOAD CONTROL MODE].

STARTER SPINS BUT DOES NOT CRANK:-

1.CHK APU FUEL DRAINS FOR FUEL DRAINAGE AFTER ATTEMPTED START, IF FUEL DRAINAGE NOT PRESENT, ACCESSORY GEAR DRIVESHAFT FAILURE, REPLACE STARTER.

2.IF NOT FUEL SHRD, CHANGE STARTER.

STARTER MOTOR CRANKS BUT NO EGT RISE:-

1.CHK FOR FIRING OF IGNITER PLUG.

2.OPN OF LOP1 SW, SHORT TERMINAL 3 & 4,IF LOP1 SW DEFECTIVE AND ATTEMPT TO START APU.

3.CHK FOR FUEL SUPPLY TO FUEL ATOMIZER. [REMOVE FUEL ATOMIZER, MOTOR APU, AND CHK FOR FUEL FLOW], IF NO FUEL FLOW, CHK APU FSOV, FUEL SOLENOID VALVE, FCU.

4.CHK FOR ACC LIMIT CRACK PR, ADJUST IF REQD.

TRIM RUN PROCEDURE:-

POWERPLANT TRIMMING IS REQUIRED TO ADJUST IDLE TPM, CHK THRUST LEVER CUSHION AND MINIMIZE THRUST LEVER STAGGER.

ENGINE TRIMMING IS PERFORMED AT PART POWER SETTING.

AIRCRAFT HEAD INTO THE WIND [WIND VELOCITY NOT > 10 MPH], AND NO ICING CONDITION PREVALING

NOTE AMBIENT TEMPERATURE AND PRESSURE. USING TRIM TABLES, GET TARGET VALUES OF:-

1.IDLE TARGET IN % N2 RPM.

2.PART POWER EPR AND PT7.

3.TAKE OFF EPR.

4.DATA PLATE CORRECTION. [FOR CONDITION RUN AT 1.65 EPR].

IF TARGET RIGHT OF STAGGERED LINE USE "C" STOP, OTHERWISE USE "S" [STD] STOP.

1.START ENGINE.

2.ALLOW 5 MINUTES FOR ENGINE TO STABLIZE.

3.NO LOAD, NO BLEED CONDITION.

4.ADJUST IDLE TRIM SCREW TO GET IDLE N2 TARGET.

TOLERANCE -9A [+2.0/-1.0% N2] -17/17A [+0.0/-1.0% N2].

NOTE:-TURN IDLE AND MIL TRIM SCREW CLOCKWISE TO REDUCE RPM.

5.ADVANCE THRUST LEVER TO PP, CHK OPN OF SURGE BLEED VALVE, RECORD N1 [N1 8% RISE & EPR 0.06 RISE ON CLOSING].

6.ADJUST MIL TRIM TO GET TARGET EPR

7.RETARD TO IDLE AND ADJUST IDLE IF REQD.

8.ADVANCE TO PP EPR AND RECORD ALL ENGINE PARAMETERS.

9.RECORD IDLE POWER ENGINE PARAMETERS.

10.DEACTIVATE PP TRIM STOP.

11.INCREASE TO T/O EPR AND CHK THROTTLE CUSHION.

12.CARRY OUT ACCELERATION CHK [5 TO 6 SECS].

13.RECORD T/O EPR ENGINE PARAMETERS.

14.IDLE ENGINE FOR 5 MINUTES AND THEN SHUT DOWN ENGINE. CHK REVERSE THRUST DETENT, IF REQD.

AMB TEMP =

AMB PRESSURE =

TARGET IDLE N2 = %

TARGET PP EPR = PP PT7 = % N2

TARGET T/O EPR = STOP:- S OR C

DATA PLATE CORR =

DATA PLATE RPM = [FROM DATA PLATE ON ENGINE]

CORR DATA PLATE RPM

N1 OIL PR N2 EGT EPR OIL TEMP F/F

IDLE

PP EPR

1.65 EPR

T/O EPR

 

ACCELERATION [IDLE TO 95% T/O EPR].

MAX TIME 6 SECONDS.

THRUST LEVER CUSHION:-

BLEED VALVE:-CLOSING:-

OPENING:-

 

EXPLOSIVE 'BANG' OR FLAME OUT OF TAIL PIPE AT START:-

1.CHK OIL SCREEN FOR METAL PARTICLES, IF FOUND, CHANGE FILTER, RUN APU FOR 1 MINUTE AND RECHECK. REPLACE APU IF METAL PARTICLES FOUND AGAIN.

2.CHK LOP1 S/W.

3.CHK FUEL SOLENOID VALVE AS WELL AS IGNITION SYSTEM FOR OPERATION.

4.CHK FOR CLOGGING OF COMBUSTER FUEL DRAIN, TURBINE FUEL DRAIN + DRAIN FROM APU LOWER SHROUD TO DRAIN MAST.

INDICATED NO LOAD FREQUENCY NOT WITHIN 405 TO 410 HZ.

ADJUST GOVERNOR ON FCU.

BLEED LOAD CONTROL CAN BE APPLIED AT 100 % RPM:-

1.ADJUST LOAD CONTROL VALVE.

2.CHK AIR REGULATOR FILTER [APU BV]

3.REPLACE APU BV.

APU EGT KEEPS ON CLIMBING DURING START:-

THE TROUBLE MAY EITHER BE DUE TO FAULTY LOAD CONTROL THERMOSTAT,3 WAY PNEUMATIC SOLENOID VALVE OR APU FCU.

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