DATE REV MODEL AFFECTED: SUBJECT: 

## TECHNICAL BULLETIN 

## Bell Helicopter

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222U No . Date Page

FUEL VALVE SWITCH, REWIRING OF HELICOPTERS AFFECTED: Model 222U helicopters serial number 47501 through 47574 222U-03-96 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 10648BH 1-1 , 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 of this 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 facilities available . MATERIALS: None SPECIAL TOOLS: M81969/14-11 Insertion/Extraction tool AN APPROPRIATE ENTRY SHOULD BE MADE IN THE AIRCRAFT LOGBOOK UPON ACCOMPLISHMENT IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNERTB 222U-03-96 Page 2 of 8 WEIGHT AND BALANCE: Not affected ELECTRICAL LOAD DATA: Not affected REFERENCES: BHT-222U-MM-1 0 Maintenance Manual BHT-222U-MM-12 Maintenance Manual PUBLICATIONS AFFECTED: BHT-222U-MM-10 Maintenance Manual BHT-222U-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): Q151A22 from position 5, Q121A22 from position 6, J5A22 from position 7, J6A22 from position 8, L123A22 from position 10, L122A22 from position 11 . Q227A22N from position 14, Q146A22 from position 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 6,0151A22 into position 7, 0121A22 into position 8, L122A22 into position 10, L123A22 into position 11, 0227A22N into position 13, 0144A22 into position 16, 0146A22 into position 17. 8. Locate the No .2 engine Fuel Valve Switch (1 S8) . TB 222U-03-96 Page 3 of 8

9. Using an extraction tool , P/N M81969/14-11 , remove the following wires from switch (1S8) : 0149A22 from position 5, 0148822 from position 6, J1A22 from position 7, J2A22 from position 8, L109A22 from position 10, L108A22 from position 11 . 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, 0149A22 into position 7, 0148822 into position 8, L108A22 into position 10, L109A22 into position 11 , 0228A22N into position 13, 0140A22 into position 16, 0141A22 into position 17. 11 . Carefully raise the overhead control console and re-secure . 12 . Push the ENG 1 FUEL VALVE switch (1S3) and the ENG 2 FUEL VALVE switch (1 S8) to the "in" position. 13. Apply a 28 Vdc power source to the aircraft. (8HT-222U-MM-10). 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.TB 222U-03-96 Page 4 of 8 c. The ENG 1 FUEL VALVE caution panel segment will come on for as long as the fuel shut valve is operating .. 15. Push the ENG 2 FUEL VALVE switch (1S3) to ON and observe the following : a. The green light of the 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. Set the ENGINE 1 ARM fire extinguisher switch 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. Set the ENGINE 1 ARM fire extinguisher switch to NORM and the ENG 1 FUEL VALVE switch to OFF. 19. Set the ENGINE 2 ARM fire extinguisher switch 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. Set the ENGINE 2 ARM fire extinguisher switch to NORM and the ENG 2 FUEL VALVE switch to OFF. 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-222U-MM-10) . 22 . Annotate the helicopter records to reflect compliance with this bulletin . 23. Return the helicopter to flight status .RE-TERMINATION WIRE CHART WIRE NO. REF DES FROM PIN J5A22 1 S3 7 J6A22 1S3 8 L122A22 1S3 11 L123A22 1S3 10 Q121A22 1S3 6 Q144A22 1S3 17 Q146A22 1S3 16 Q151A22 1S3 5 Q227A22N 1S3 14 JIA22 1S8 7 J2A22 1S8 8 L108A22 1S8 1 1 L109A22 1S8 10 Q140A22 1S8 17 Q141A22 1S8 16 0148822 1S8 6 Q149A22 1S8 5 Q228A22 N 1 S8 14



### Figure 1 Wire Termination Chart TO PIN 5 6 10 11 8 16 17 7 13 5 6 10 11 16 17 8 7 1 3 TB 222U-03-96 Page 5 of 8TB 222U-03-96 Page 6 of 8

1 

### TOP 

### c 2



### Figure 2 Switch Termination Schematic) )

) 

### \ ENG 1 FUEL VALVE SWITCH 

## I 1S3 

## I L48C22 --2 

### TB 222U-03-96 Page 7 of 8

- L122A22



## s-- J6A22 L42C22N --2

PRE MOD

ENG 1 FUEL VALVE SWITCH 

## I 1S3 

## I

POST MOD



### Figure 3 JSA22 -----------------r Q151A22 --------T' L42C22N--2 Q155E22 ---,-> Q123A22 ---T'

03536001



### No.1 Fuel Valve Switch Wiring DiagramTB 222U-03-96 Page 8 of 8

'

) ' l 

### s--- J2A22 ENG 2 FUEL VALVE SWITCH 

### I 1s8 

### I L47K22 ------(

L43C22N -----(

PRE MOD

ENG 2 FUEL VALVE SWITCH 

## I 1s8 

## I

J1A22 ---------.' Q149A22 ----------r' L42C22N -----( Q157E22 ------2 Q122A22 ---r' POST MOD

03536002 

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