DATE REV MODEL AFFECTED: SUBJECT: 

## TECHNICAL BULLETIN 

## Bell Helicopteri

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**~I** A Subsidiary of Textron Inc.

230 No . Date Page

FUEL VALVE SWITCH, REWIRING OF HELICOPTERS AFFECTED: Model 230 helicopters serial number 23001 through 23038 230-03-35 06-11-03 1 of 8

COMPLIANCE: Bell Helicopter recommends compliance with this bulletin . DESCRIPTION: We have received field reports of failure of the switches, P/N 10648BH1-1, that control the operation of the No . 1 and No . 2 engine fuel valves. There is a possibility that the switch may fail in flight , due to vibration , causing the switch to open and then causing the fuel valve to revert to the closed condition and subsequent shut down of the associated engine . APPROVAL: The engineering design aspects ofthis bulletin are Transport Canada approved. MANPOWER: Approximately 4.0 man-hours are required to complete this bulletin . Man-hours are based on hands-on time , and may vary with personnel and facil ities available . MATERIALS : None

AN APPROPRIATE ENTRY SHOULD BE MADE IN THE AIRCRAFT LOGBOOK UPON ACCOMPLISHMENT IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER

# . TB 230-03-35 Page 2 of 8 SPECIAL TOOLS: M81969/14-11 Insertion/Extraction tool WEIGHT AND BALANCE: Not affected ELECTRICAL LOAD DATA: Not affected REFERENCES: BHT-230-MM-1 0 Maintenance Manual BHT-230-MM-12 Maintenance Manual PUBLICATIONS AFFECTED: BHT-230-MM-10 Maintenance Manual BHT-230-MM-12 Maintenance Manual ACCOMPLISHMENT INSTRUCTIONS: 1 . Prepare the helicopter for maintenance 2. Ensure all electrical power is removed from the helicopter. 3. Disconnect the aircraft battery. 4 . Carefully lower the overhead console. 5. Locate the No . 1 engine Fuel Valve Switch (1 S3) . 6. Using an extraction tool, P/N M81969/14-11 , remove the following wires from switch (1 S3) : J5A22 from position 7, J6A22 from position 8, L123A22 from position 1 0, 

### L122A22 from position 11. Q121A22 from position 13, Q227A22N from position 14, Q1 46A22 from positi on 16 , Q144A22 from position 17. 7. Using an insertion tool , P/N M81969/14-11 , insert the following wires into switch (1 S3) :J5A22 into position 5, J6A22 into position 6, L122A22 into position 10 , L123A22 into position 11 , 0227A22N into position 13, 0121A22 into position 14 , 0144A22 into position 16 , 0 146A22 into position 17. 8. Locate the No.2 engine Fuel Valve Switch (1 S8). TB 230-03-35 Page 3 of 8

9. Using an extraction tool, P/N M81969/14-11, remove the following wires from switch (1 S8): J1A22 from position 7, J2A22 from position 8, L 1 09A22 from position 10, L108A22 from position 11 . 0148822 from position 13, 0228A22N from position 14, 0141A22 from position 16, 0 140A22 from position 17. 10 . Using an insertion tool, P/N M81969/14-11 , insert the following wires into switch (1 S8): J1A22 into position 5, J2A22 into position 6, L 108A22 into position 10, L109A22 into position 11, 0228A22N into position 13, 0148822 into position 14, 0140A22 into position 16, 0141A22 into position 17 . 1 1. Carefully raise the overhead control console and re-secure . 12. Push the ENG 1 FUE L VALVE switch (1 S3) and the ENG 2 FUE L VALVE switch (1 S8) to the "in" positio n. 13 . Apply a 28 Vdc power source to the aircraft. (8HT-230-MM-1 0). 14. Push the ENG 1 FUEL VALVE switch (1S3) to ON and observe the following: a. The green light of the switch comes on. b. The engine No.1 fuel valve opens . c. The ENG 1 FUEL VALVE caution panel segment will come on for as long as the fuel shut valve is operating ..TB 230-03-35 Page 4 of 8 15. Push the ENG 2 FUEL VALVE switch (1S3) to ON and observe the following: a. The green light ofthe switch comes on. b. The engine No.2 fuel valve opens . c. The ENG 2 FUEL VALVE caution panel segment will come on for as long as the fuel shut valve is operating . 16. Open the engine No. 1 and engine No.2 FIRE EXTG circuit breakers (24CB1 and 24CB2). 17. Push in the FIRE/ARM/ENG 1 switch (1DS1) to ARM and observe the following: a. The engine No.1 fuel valve closes . b. The ENG 1 FUEL VALVE caution panel segment will come on for as long as the fuel shut valve is operating. 18. Push the FIRE/ARM/ENG 1 switch . 19. Push in the FIRE/ARM/ENG 2 switch (1 DS2) to ARM and observe the following : a. The engine No .2 fuel valve closes . b. The ENG 2 FUEL VALVE caution panel segment will come on for as long as the fuel shut valve is operating. 20. Push the FIRE/ARM/ENG 2 switch . 21 . Close the engine No.1 and engine No .2 FIRE EXTG circuit breakers (24CB1 and 24CB2). 21 . Carry out an operational test of the ignitor system . (BHT-230-MM-1 0). 22 . Annotate the helicopter records to reflect compliance with this bulletin . 23. Return the helicopter to flight status.WIRE NO. 

### JIA22 J2A22 L108A22 L109A22 Q140A22 Q141A22 0148822 Q228A22N J5A22 J6A22 L122A22 L123A22 Q121A22 Q144A22 Q146A22 Q227A22N RE-TERMINATION WIRE CHART REF DES FROM PIN 

### 188 7 188 8 188 11 188 10 188 17 188 16 188 13 188 14 183 7 183 8 183 11 183 10 183 13 183 17 183 16 183 14



### Figure 1 Wire Termination Chart TO PIN 

### 5 6 10 11 16 17 14 13 5 6 10 11 14 16 17 13 TB 230-03-35 Page 5 of 8TB 230-03-35 Page 6 of 8



### TOP 1 

## c 2



### Figure 2 Switch Termination Schematic**(~ ------r-------~---J6A22**  ENG 1 FUEL VALVE SWITCH 

### I 1s3 

### I L48822-----(

L42E22N -----2

PRE MOD

ENG 1 FUEL VALVE SWITCH 

### I 1s3 

### I TB 230-03-35 Page 7 of 8

L48822 ---( 

# l ON**(~----~r------------- J6A22** 

POST MOD

03538001 

### Figure 3 No.1 Fuel Valve Switch Wiring DiagramTB 230-03-35 Page 8 of 8

**~------~------4-----J2A22**

:r------rr------------- J2A22 ENG 2 FUEL VALVE SWITCH 

### I 1S8 

### I L47J22 -----(

L40G22N ---r'

PRE MOD

ENG 2 FUEL VALVE SWITCH 

## I 1S8 

## I L47J22 ---<' 

## 1 ON

L40G22N ---r'

POST MOD 

### Figure 4 No.2 Fuel Valve Switch Wiring Diagram 03538002