# STC ST12331IB - Type: Supplemental type certificate - Status: Current, Issued - Holder: Avmax Aviation Services Inc. - Description: Installation and maintenance of the Slip Ring De-Icer Harness - Status date: March 3, 2026 - Data sheets: A13NM - Certificate PDF: https://openairdocs.org/files/sha256/30/8a/308ab4abb59b6a45f39a7d9066c5043dbc83ae8bb2ce9e5aeefd26566e2b5edd - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID185591437220260303144939.0001 - Page: https://openairdocs.org/stc/ST12331IB ## ADs that name it None. ## Approved models (1) - De Havilland Aircraft of Canada Limited DHC-8-400 Series (TCDS A13NM) ## What the certificate says Read from the PDF's text layer, without the form's printed wording; the layout is lost and the order can differ. The PDF is the record. 4404 - 14th Street, N.E. Calgary, Alberta Canada T2E 6T7 Part 25 Title 14, Code of Federal Regulations A13NM De Havilland Aircraft of Canada Limited DHC-8-400 Series 1. If the holder agrees to permit another person to use this certificate to alter a product, the holder must give the other person written evidence of that permission. 2. The installer must determine whether this design change is compatible with previously approved modifications. 3. This STC is applicable to all serial numbers for this Make-Model-Series. 09/26/2025 03/03/2026 John Yoo Manager, International Validation Branch Compliance & Airworthiness Division Aircraft Certification Service 2 1. Installation and maintenance of the Slip Ring De-Icer Harness must be done in accordance with Avmax Maintenance Manual Supplement CE551-700-01, Issue A, dated September 17, 2025, or later Transport Canada Civil Aviation (TCCA) accepted revision. 2. Definition of the Type Design Change: Avmax Master Data List CE551-000, Issue A, dated September 23, 2025, or later TCCA approved revision. ## Every issue (1) - March 3, 2026: Issued, Current. [certificate](https://openairdocs.org/files/sha256/30/8a/308ab4abb59b6a45f39a7d9066c5043dbc83ae8bb2ce9e5aeefd26566e2b5edd) --- From OpenAirDocs.org, an independent open copy of FAA data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.