SI-1175

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SUBJECT:

EFFECTIVIN:

REASON:COMPLIANCE:

CLASS I ISERVICE INSTRUCTIONS

No.1175ATA Code 77-00

ENGINE INDICATING - MODIFICATIONAND CALIBRATION OF AIRCRAFT INSTRUMENT ANDDEVELOPMENT INCORPORATED ENGINE INSTRUMENT CLUSTERSNOTE

These Service Instructions supersede and cancel BEECHCRAFT Servicelnstructions No. 1065.

BEECHCRAFT Duchess 76, serials ME-1 through ME-349;Skipper 77, serials WA-1 through WA-101 and WA-104;and any other Duchess 76 and Skipper 77 airplanes which may have installeda replacement engineinstrument cluster manufactured by Aircraft Instrument and Development Incorporated with any ofthe following serial numbers:MODEL ENGINE INSTRUMENTCLUSTER PART NUMBER

105-389011-5 (14 voltsystem)or105-389011 31 (28 voltsystem)

NOTE

ENGINE INSTRUMENTCLUSTER SERIALNUMBER1 through 419, 1000through 1068 and 1088through 1091

1 through 279

These Service lnstructions affect only engine instrument clustersmanufactured by Aircraft Instrument and Development Incorporated. Otherengine instrument clusters are not affected.

To provide improved reliability of the engine instrument cluster.At the owner's discretion, however, Beech Aircraft Corporation recommends that this modificationbeaccomplishedand the engine instrument cluster be recalibrated the next time the engine instrumentcluster is removed from the airplane for any type of maintenance.

No BECP301 11

Beech Alrcraft Corporat~onssues servtce lnformatton for the benef~t f ownersand flxed base operators In the form of three classes of Service lnstructlonsCLASS I (Red Border) are changes tnspectlons, and rnod~ftcattonshat couldaffect safety The factory cons~ders ornpl~ancemandatory CLASS II (GreenBorder) covers changes modlflcat~ons,mprovements or lnspectlonsthe factoryfeels will beneftt the owner and although h~ghly ecommended, they are notcons~deredmandatory cornpl~ance,~nless pec~ftedat the tlrne of Issuance8 Class I and II are malted to.Nv (a) BEECHCRAFT Aero or Avtat~onCenters and Intervat~onal3 D~str~butorsnd Dealers8 (b) Owners of record on the FAA Reg~strationfst a id the

BEECHCRAFT InternattonalOwner NotificationService List.(c) Those havlng a publications subscript~on.CLASS Ill (No Border) covers changes whlch are opttonal, matntenance a~ds.product Improvement k~ts nd miscellaneous servlce lnforrnat~onCornpltance 1sat the owner or operators prerogarlve Coptes of Class Ill are dlstrtbuted per aand c above lnformat~onn Owner Not~ftcatton ervice or Subscr~ptlonsan beobtalned through any BEECHCRAFT Aero or Av~atlonCenter, lnternat~onalDlstrlbutor and Dealer or the Factory As Service lnstruct~ons re ~ssued.temporary notatlon In the Index should be made until the tndex 1s revlsedWarranty will be allowed only when spec~flcally eflned In the Servlce lnslructlonsand In accordance wlth Beech Warranty Poltcy 43 M emb e r 01 G A M A

Generat. nv fac lurc r%vw#nonnooot8on

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Service lnstructions No. 1175APPROVAL: FAA Approved.MANPOWER: The following information is for planning purposes only:

Estimated man-hours: 4 hours.Suggested number of men: 1 man.MATERIAL: The following parts required for this modification may be ordered through BEECHCRAFT Aero orAviation Centers and International Distributors and Dealers.

WARRANTY:

PART NUMBER DESCRIPTION

Mylar Strip

QUANTITY PERAIRPLANE12 (Duchess 76)6 (Skipper 77)

'476 Black Vinyl Tape As Required

*PIN of Minnesota Mining and Manufacturing Company, 3M Center, St. Paul, Minnesota 55101. Maybe obtained from local sources.The value of the parts required to incorporate these Service lnstructions on one airplane is to beadvised. Prices, when issued, will be subject to change without notice.

BEECHCRAFT Warranty on a new airplane is 180 days from delivery or 180 days from the datenoted on the Owner Warranty Card. Warranty credit for parts and labor to the extent noted underMATERIAL and MANPOWER will be allowed on BEECHCRAFTS within warranty at the time theseService lnstructions are released.All warranty reimbursements are handled through franchised BEECHCRAFT Aero or AviationCenters and International Distributors and Dealers. Owners and operators should arrange with theseoutlets to perform the work and have them submit the standard Beech Aircraft Corporation warrantyclaim form through BEECHCRAFT Parts and Equipment Marketing Wholesalers or InternationalDistributors.

SPECIALTOOLS:

WEIGHT ANDBALANCE:REFERENCES:

None.

None.BEECHCRAFT Duchess 76 Maintenance Manual, PIN 105-590000-7 or subsequent, Chapter 77-00;BEECHCRAFT Skipper 77 Maintenance Manual, PIN 108-590000-7 or subsequent, Chapter 77-00;BEECHCRAFT Duchess 76 Wiring Diagram Manual (14 Volt), PIN 105-590000-158 or subsequent,Chapter 77-20;BEECHCRAFT Duchess 76 Wiring Diagram Manual (28 Volt), PIN 105-590000-21 or subsequent,Chapter 77-20;BEECHCRAFT Skipper 77 Wiring Diagram Manual, PIN 108-590000-158 or subsequent, Chapter91 -15.

PUBLICATIONSAFFECTED: It is recommended that a note to "See Service Instructions No. 1175" be made in the following:

BEECHCRAFT Duchess 76 Maintenance Manual, PIN 105-590000-7or subsequent, Chapter 77-00;BEECHCRAFT Skipper 77 Maintenance Manual, PIN 108-590000-7 or subsequent, Chapter 77-00;BEECHCRAFT Duchess 76 Parts Catalog, PIN 105-590000-9B or subsequent, Chapter 39-10;BEECHCRAFT Skipper 77 Parts Catalog, PIN 108-590000-9 or subsequent, Chapter 39-10.

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Service Instructions No. 1175ACCOMPLISHMENT These Service lnstructions may be accomplished as follows:INSTRUCTIONS:

1. Turn off andlor disconnect all electrical powerand disconnect the battery.

2. Remove the instrument panel glareshield.3. Inspect the engine instrument cluster anddetermine if it was manufactured by Aircraft Instrument andDevelopment Incorporated.4. If the engine instrument cluster was notmanufactured by Aircraft lnstrument and DevelopmentIncorporated, reinstall the glareshield and reconnect thebattery. No further action i s necessary.5. I f the engine instrument c luster wasmanufactured by Aircraft lnstrument and Developmentlncorporated but does not have one of the serial numberslisted under EFFECTIVITY, reinstall the glare shield andreconnect the battery. No further action is necessary.6. I f the engine instrument c luster wasmanufactured by Aircraft lnstrument and Developmentlncorporated and does have one of the serial numberslisted under EFFECTIVITY, continue with step 7.7. Refer to the Maintenance Manual, Chapter 77-00and remove the engine instrument cluster.

NOTESteps 8 through 15 must be accomplished byan appropriately rated instrument repair facility.

8. Refer to the wiring diagrams in Figures 4, 5 and6 and repair the engine instrument cluster i f required.9. Prior to reassembling the cluster, remove anyand all tape that may be found around the metermovements and on the inside of the face mask. Install PIN49-0037mylar strips on the front of each meter movementby securing the strips under the heads of the screws thatattach the dial face to the meter movement as shown inFigure 1.

L ~ l T ~ ~ ~PIN 49-0037MYLARSTRIP UNDER THE DIAL FACEMOUNTING SCREWS ON THEFRONT OF EACH METER

Figure 1

10. Using a magnifying glass, inspect each metermovement for dirt and debris. Pay particular attention tothe area between the armature and the magnet in eachmeter movement. Clean the meter movements asnecessary.

1 1 . Using the resistance and voltage values specifiedin Table 1 , calibrate the engine instrument cluster asfollows:NOTE

Before applying power to the engine instrumentcluster, test resistances must be connected tothe pins corresponding to each module to betested or the unused pins should be groundedto prevent damage to the meter movements.Any pin left open may cause the correspondingmeter movement to go rapidly to full scale andpossibly damage the meter movement.

a. Connect a regulated 14 volt DC (for PIN105-38901 -5and PIN 108-384003-23)r 28 volt DC (forPIN 105-38901 -31)power supply to pin 1 of engineinstrument cluster electrical connector. Connect pin 2 toground. Ground the chassis of the power supply to theinstrument cluster case.

b. For fuel quantity, fuel pressure, oil pressure,oil temperature and cylinder head temperature indicators,connect the appropriate resistance for the low scaleindication as specified in Table 1 between the appropriatepin of the electrical connector (see Table 2) and ground.Adjust the zero (Z) adjustment potentiometer (see Figure2)so the meter reads at the low scale mark on the meterdial face.

c. Connect the appropriate resistance for thehigh scale indication from Table 1 in place of theresistance used in step 1 1 b and adjust the span (S)adjustment potentiometer (see Figure2)so the meter readsat the high scale mark on the meter dial face.

d. Substitute resistances for the variousmidrange indications from Table 1 for the resistance usedin step llc and observe that the meter indicates within1/16 nch of the appropriate mark on the meter dia! face.

e. On PIN 105-38901 -5 and 105-38901 -31engine instrument clusters only, connect a variable powersupply to pin 1 1 (see Table 2).Set the voltage at 14 or 28volts, as applicable, and gradually reduce the voltage untilthe undervoltage light is illuminated. The light shouldilluminate at 12.2+ .1 volts on 14 volt clusters and 23.75?.5 volts on 28 volt clusters. The undervoltage circuitpotentiometer (see Figure 2) should be adjusted withinthese limits. Clockwise increases the voltage at which thelight illuminates.

f. On PIN 108-384003-23 ngine instrumentclusters only, connect a 0-50 ohm 10 turn linearpotentiometer between pin 4 (see Table 2)and ground andgradually reduce the resistance. The LH fuel quantity gageshould drop and the low fuel light should illuminate at 1 1 -

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Service Instructions No. 1175/ RH FUEL QUANTITY

DUCHESS 76 INSTRUMENT CLUSTERADJUSTMENT POINTS(105-38901 -5& 105-38901 -31)DUCHESS 76 INSTRUMENT CLUSTERUNDER VOLTAGE CIRCUIT ADJUSTMENTS(1 05-38901 -5& 105-38901 -31)

ZERO ADJUSTMENTSPAN ADJUSTMENT SPAN ADJUSTMENT

ND SKIPPER 77 FUEL PRESSURE,OIL PRESSURE, OIL TEMPERATURE AND DUCHESS 76 LOADMETERCYLINDER HEAD TEMPERATURE GAGES OR SKIPPER 77 AMMETERFUEL PRESSURE ZEROADJUSTMENT

?

RH FUEL QUANTITYSPAN ADJUSTMENTRH FUEL QUANTITYZERO ADJUSTMENTLH FUEL QUANTITYSPAN ADJUSTMENTLH FUEL QUANTITYZERO ADJUSTMENT

SKIPPER 77 INSTRUMENTCLUSTER ADJUSTMENT POINTS(108-384003-23)

r OW FUEL POTENTIOMETER

SKIPPER 77 LOW FUEL LIGHTADJUSTMENTS (1 8-384003-23)Figure 2Engine Instrument Cluster Adjustment Points

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Service Instructions No. 1175

CHECKTO ASSURETHATTHEPIN 476 BLACK VINYL TAPEIS INTACT ALONG THE TOPEDGE OF THE INSIDE OF THEENGINE INSTRUMENT CLUSTER

ENGINE INSTRUMENTCLUSTER CASE

Figure 3Duchess 76 Engine lnstrument Cluster Case

50 MICRO AMPW 1 MA SHUNT I PIN 105-389011-29

RIGHT SIDE SAME RLP LENSEXCEPT OMIT 6 PM BEP SOCKET7219 LAMPS

WIRED

-1 4 VDC+1 4 VD C

CASE

Figure 4Duchess 76 Engine Instrument Cluster Wiring Diagram(105-38901 1-5 14 Volt)

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50 MICRO AMPW 1 MA SHUNTI PIN 105-38901 1-29- IL PRESSA@

W ERN

W RED

- 28 VDC+ 28 VDC

Figure 5Duchess 76 Engine Instrument Cluster Wiring Diagram(105-389011-31 28 Volt)

12 ohms. Resistance must be reduced very graduallybecause the low fuel light has a 3 second delay before itilluminates after the threshold has been reached. Adjustthe low fuel potentiometer (see Figure 2) to these limits.Connect the 0-50 ohm potentiometer between pin 8 (seeTable 2) and ground and repeat the procedure for the RHfuel quantity gage. Check operation of the low fuel quantitylight test switch in both the left and right positions.

g. Disconnect the power supply and groundfrom pins 1 and 2 on the engine instrument clusterelectrical connector.

h. On PIN 105-389011-5 and PIN 105-38901131 engine instrument clusters, apply voltages of 0, 25 and50 millivolts to pins 9+ and 10- (see Table 2) andobserve that the loadmeter indicates 0, 50% and 100%respectively. Meter indications should be within 1116 inchof the appropriate mark on the meter dial face. Adjust theload meter span adjustment potentiometer (see Figure 2)as required to obtain the proper readings.

i. On PIN 108-384003-23 engine instrumentclusters, apply voltages of 0, +50 and -50 millivolts to

pins 9+ and 10- (see Table 2) and observe that theammeter indications are 0, CHG and DIS respectively.Meter indications should be within 1/16 inch of theappropriate mark on the meter dial face. Adjust theammeter span adjustment potentiometer (see Figure 2) asrequired to obtain the proper readings.

12. Reassemble the engine instrument cluster intothe engine instrument cluster case.

NOTEOn PIN 105-389011-5 and 105-389011-31engine instrument clusters, check to assure thetape is intact along the top edge of the insideof the engine instrument cluster case (seeFigure 3). If necessary, replace the tape withPIN 476 black vinyl tape. This tape reduces thepossibility of the fuel quantity gages shortingagainst the engine instrument cluster case.

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8uvbo lnmucmm No. 117513. Check the operation of the engine instrument

cluster at a sufficient number of points as specified in step11 to assure that reassembly has not caused anymechanical interference and all gages operate properly.

14. Seal the outside edge between the engineinstrument cluster and the engine instrument cluster casewith PIN 476 black vinyl tape.

15. Seal all adjustment holes in the engineinstrument cluster case with PIN 476 black vinyl tape.

16. Refer to the Maintenance Manual, Chapter 77-00and adjust the fuel quantity and fuel pressure gages as

required to match the airplane system. Reseal anyadjustment holes as required with PIN476 black vinyl tape.

17. Refer to the Maintenance Manual, Chapter 77-00and reinstall the engine instrument cluster in the instrumentpanel.

18. Reinstall the glare shield and any otherequipment or panels which may have been removed toaccomplish these Service Instructions.

19. Ground run the airplane and check the engineinstrument cluster for proper operation.

7219 U M PBEP SOCKET

I

Figure 6Skipper 77 Engine Instrument Cluster Wiring Diagram(108-384003-23)

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Sewice Instructions No. 1175

MODEL 76 FUEL QTY

QTYE

114112314F

7

76 AND 77 FUEL PRESSURE

J

76 AND 77 OIL TEMPERATURE

MODEL 77 FUEL QTY

QTY I OHMS I TOL OHMSHMS625384861

TOL OHMS-t 1.9t 1.92 2.8

PSI.58

12

MODEL 76 LOADMETER

TOLt 1/16 IN

-c 1.2 OHMt 1.5 OHMt 1.5 OHM-c 1.2 OHM

OHMS12.954.576.8

TOL OHMSt 1.4r 1.4t 1.4t 1.4

OF

60120200245

Oo

050

100i

76 AND 77 OIL PRESSURE

OHMS95.74

107.96126.00137.00

MODEL 76 CYL HD TEMP

VOLTAGE0 MV

25 MV50 MV

Table 1Calibration Resistances and Voltages

TOL OHMS+ 2.4t 3.52 2.4

PSI2560

100

MODEL 77 AMMETERTOL MVt 1t 1.5-t 1.5

OHMS39.580.8

128.0

TOL OHMSt 2.0 -+ 2.0t 1.3

OF

200350500

OHMS76.8107

143.8

TOL MVt 1.5-t 1.0t 1.5

Oo

DIS0

CHG

VOLTAGE-50 MV

0 MV+50 MV

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+ 14 VDC OR + 28 VDCRIGHT FUEL QUANTITY INDICATOR (IN)RIGHT FUEL PRESSURE INDICATORRIGHT OIL PRESSURE INDICATORRIGHT OIL TEMPERATURE INDICATORRIGHT CYLINDER HEAD TEMPERATURE INDICATORLOAD METERLOAD METEROVER VOLTAGE LIGHTUNDER VOLTAGE LIGHTOPENGROUND

+ 14VDC OR +28VDCLEFT FUEL QUANTITY INDICATOR (IN)LEFT FUEL PRESSURE INDICATORLEFT OIL PRESSURE INDICATORLEFT OIL TEMPERATURE INDICATORLEFT CYLINDER HEAD TEMPERATURE INDICATORLOAD METERLOAD METEROVER VOLTAGE LIGHTUNDER VOLTAGE LIGHT+14V LIGHTS OR +28VDCGROUND

+ 14VDCGROUND+ 14 VOLT LIGHTSLH FUEL QUANTITYFUEL PRESSUREOIL PRESSUREOIL TEMPERATURERH FUEL QUANTITYAMMETER +AMMETER -OPENOPEN

MODELn108-384003-23(14 VOLT)

MODEL 76105-389011-5 (14 VOLT) 105-389011-31 (28 VOLT)

Table 2Engine Instrument Cluster Electrical Connectors

RECORDCOMPLIANCE: Upon completion of these Service Instructions, make an appropriate maintenance record entry.

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