# Bell Alert Service Bulletin 412-20-180: No revision named - Rights: © Bell Textron Inc. Filed by the FAA in regulations.gov docket FAA-2022-0006; AD 2022-07-02 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Bell Alert Service Bulletin 412-20-180](https://openairdocs.org/service-documents/bell/sb-412-20-180.md) - Title as filed: Bell ASB 412-20-180 - Pages: 4 - PDF: https://openairdocs.org/files/sha256/46/bb/46bb078bfdd010d86d0e9005267a19ca9ff913bc21ffda9d29d04a8d53743cd6 - Page: https://openairdocs.org/service-documents/bell/sb-412-20-180/file/46bb078bfdd0 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 412-20-180 Page 1 of 4 Approved for public release. ALERT SERVICE BULLETIN 412-20-180 15 April 2020 MODEL AFFECTED: 412/412EP SUBJECT: TAILBOOM LEFT HAND FIN SPAR CAP P/N 212 - 030-447-117, INSPECTION OF. HELICOPTERS AFFECTED: Serial number s 33001 through 33213, 34001 through 34036, 36001 through 36999, 37002 through 37999 , 38 001 through 38999 and 39101 through 39999. COMPLIANCE: Within the next 100 flight hours or 90 days whichever occurs first after the release date of this bulletin and every 100 flight hours thereafter. DESCRIPTION: Bell has received a report of a fractured fin spar cap P/N 212-030-447-117. The crack occurred at vertical fin station (F.S.) 71 through the first rivet hole attaching the skin 212-030-099-105 to the spar cap. If undetected, the fin spar cap cracking may lead to additional structural damage. This bulletin introduces a 100 flight-hour inspection of the affected area of the fin spar cap using 10X magnifying glass. Applicability of this bulletin to any spare part shall be determined prior to its installation on an affected helicopter. APPROVAL: The engineering design aspects of this bulletin are FAA approved for FAA certified helicopters as listed in the applicable Type Certificate Data Sheet. For non FAA certified helicopters, the engineering design aspects of this bulletin are Bell Engineering approved. ### Page 2 412-20-180 Page 2 of 4 Approved for public release. 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 1 man-hour is 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: None required. Consumable Material: None required. SPECIAL TOOLS: None required. WEIGHT AND BALANCE: Not affected. ELECTRICAL LOAD DATA: Not affected. REFERENCES: No reference. PUBLICATIONS AFFECTED: BHT-412-MM Maintenance Manual. ### Page 3 412-20-180 Page 3 of 4 Approved for public release. ACCOMPLISHMENT INSTRUCTIONS: 1. Prepare the helicopter for maintenance. 2. Gain access to the spar cap angle by r emoving the 42-degree gearbox cover and opening the vertical fin driveshaft cover. 3. Clean exposed surfaces of spar cap to facilitate inspection. 4. Inspect both flanges of the spar cap between F.S. 50 and F.S. 71 using 10 x magnifying glass and a bright light for cracks, loose rivets and other damage (Figure 1). 5. Inspect the exterior of the fin skin in the area in contact with the spar cap for cracks, loose rivets and/or distortion. 6. If no cracks or other damage is found , close the driveshaft cover , reinstall the 42 - degree gearbox cover and return the helicopter to service. 7. If a crack or other damage is found, contact Product Support Engineering before further flight: Bell Product Support Engineering Tel: 1-450-437-2862 / 1-800-363-8023 / productsupport@bellflight.com 8. Make an entry in the helicopter logbook and historical service records indicating findings and compliance with this Alert Service Bulletin. ### Page 4 (OCR) SEE DETAIL A 50 IN. (1270 mm) FIN STA 50 Area to be inspected with 10x power magnafying glass FIN STA 71 INSPECT THESE AREAS HINGE * INSPECT THIS AREA DETAIL A WEB SPAR CAP — SKIN (PARTS OMITTED FOR CLARITY) SECTION B-B 19898_001 Figure 1. Spar cap inspection. 412-20-180 Page 4 of 4 Approved for public release. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.