TECHNICAL BULLETIN 407-20-133

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TB 407-20-133 Page 1 of 8 Approved for public release. TECHNICAL BULLETIN 407-20-133 16 October 2023 MODEL AFFECTED: 407 SUBJECT: ENGINE TORQUE, ENGINE OIL PRESSURE, AND TRANSMISSION OIL PRESSURE INDICATION SYSTEMS, MODIFICATION OF HELICOPTERS AFFECTED: Part I: Serial numbers 53000 through 53900, 53911 through 54166, 54300 through 54752, 54805 through 54929. Part II: Serial numbers 54304, 54567, 54805 through 54929. [Serial numbers 54930 and subsequent will have the intent of this bulletin accomplished prior to delivery.] COMPLIANCE: At customer’s option. DESCRIPTION: This technical bulletin provides instructions to modify the engine torque transducer (1B7), the engine oil pressure transducer (1G5) and the transmission oil pressure transducer (1G6) wire harness installations to reduce the possibility of water ingress in the transducer connectors. PART I of this technical bulletin provides instructions to replace the connectors MS3116F8-4S with new connectors 160-027-508, and add heat shrink sleeves on each transducer wire harness to fill the gap between the wires and the connector inserts. PART II of this technical bulletin provides instructions to re-orient clamps to improve water drip loops. Applicability of this bulletin to any spare part shall be determined prior to its installation on an affected helicopter. TB 407-20-133 Page 2 of 8 Approved for public release. APPROVAL: The engineering design aspects of this bulletin are Transport Canada Civil Aviation (TCCA) approved. CONTACT INFO: For any questions regarding this bulletin, please contact: Bell Product Support Engineering Tel: 1-450-437-2862 / 1-800-363-8023 / productsupport@bellflight.com MANPOWER: Approximately 12 man-hours are required to complete this bulletin. This estimate is based on hands-on time and may vary with personnel and facilities available. WARRANTY: There is no warranty credit applicable for parts or labor associated with this bulletin. MATERIAL: Required Material: The following material is required for the accomplishment of this bulletin and may be obtained through your Bell Supply Center. Part Number Nomenclature Qty (Note) 10-597817-351 Contact 12(1) 2530-00246-00 Heat shrink sleeve 1 foot (0.31m)(2) 160-027-508 Connector 3(2) NOTES: 1. Not required for helicopters serial numbers 53000 through 54012. 2. Part number is for quantities sold by the foot. Actual quantity required must be specified in the order. 3. Only required for helicopters serial numbers 53000 through 54012. Consumable Material: The following material is required to accomplish this bulletin, but may not require ordering, depending on the operator’s consumable material stock levels. This material may be obtained through your Bell Supply Center. TB 407-20-133 Page 3 of 8 Approved for public release. Part Number Nomenclature Qty (Note) Reference * 2000-00731-00 Insulation tape. 1 Roll (1)(2) C-548 PLT2S-C702Y Cable Tie AR C-292 * C-XXX numbers refer to the consumables list in the BHT-ALL-SPM, Standard Practices Manual NOTES: 1. Quantity indicated is the format that the product is delivered in. Actual quantity required to accomplish the instructions in this bulletin may be less than what has been delivered. 2. Only required for PART II. SPECIAL TOOLS: 11-6782 Insertion tool (or equivalent) 11-6900 Extraction tool (or equivalent) 45-1987 Wire stripper (or equivalent) HT-900 Raychem heat gun (or equivalent) TH254 Turret/Positioner M22520/1-01 Crimp tool WEIGHT AND BALANCE: Not affected. ELECTRICAL LOAD DATA: Not affected. REFERENCES: 407-MM, Maintenance Manual, chapter 95 407-MM, Maintenance Manual, chapter 96 407-MM, Maintenance Manual, chapter 53 BHT-ELEC-SPM, Electrical Standard Practices Manual BHT-ALL-SPM, Standard Practices Manual PUBLICATIONS AFFECTED: 407-IPB, Illustrated Parts Breakdown, chapter 95 407-MM, Maintenance Manual, chapter 98 TB 407-20-133 Page 4 of 8 Approved for public release. ACCOMPLISHMENT INSTRUCTIONS: PART I: Replacement of connector and addition of heat shrink sleeve 1. Prepare the helicopter for maintenance. 2. Make sure all electrical power is removed from helicopter. WARNING OBEY ALL THE SAFETY PRECAUTIONS WHEN YOU DO MAINTENANCE ON OR NEAR ELECTRICAL/ELECTRONIC EQUIPMENT (407-MM, chapter 96). -NOTE- The engine oil pressure transducer (1G5) is not installed on the 407GXi. Only the engine torque transducer (1B7) and the transmission oil pressure transducer (1G6) are affected by PART I for the 407GXi. 3. Gain access to the engine torque transducer (1B7), the engine oil pressure transducer (1G5) and the transmission oil pressure transducer (1G6) connectors on the transmission deck by removing the air inlet cowling assembly (DMC-407-A-53- 04-00-02A-520A-A). 4. Disconnect the engine torque transducer (1B7), the engine oil pressure transducer (1G5) and the transmission oil pressure transducer (1G6) connectors 1B7P1, 1G5P1 and 1G6P1 (BHT-ELEC-SPM). -NOTE- Mark each wire with the connector pin number before extracting the contacts. 5. Disassemble the connectors and extract all wires from the connectors 1B7P1, 1G5P1 and 1G6P1 (BHT-ELEC-SPM). -NOTE- It could be required to cut and replace the contact for the heat shrink sleeve installation. TB 407-20-133 Page 5 of 8 Approved for public release. 6. Install and apply heat to the heat shrink sleeve (1, Figure 1), and install a new contact (2) on each wire as shown in Figure 1 (BHT-ELEC-SPM). -NOTE- For helicopter serial numbers 53000 through 54012, It is required to replace the connectors 1B7P1, 1G5P1 and 1G6P1 with new connectors 160-027-508. 7. Insert all wires into the connectors 1B7P1, 1G5P1 and 1G6P1, and assemble the connectors as removed in step 5 (BHT-ELEC-SPM). 8. Connect the connectors 1B7P1, 1G5P1 and 1G6P1 to the engine torque transducer (1B7), the engine oil pressure transducer (1G5) and the transmission oil pressure transducer (1G6) (BHT-ELEC-SPM).