{"id":"F2006B09143","name":"AD/DHC-6/55 - Fuel Boost Pumps - Inspection, Replacement, Modification","slug":"ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115705,"registerId":"commonwealth-F2006B09143-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/55 - Fuel Boost Pumps - Inspection, Replacement, Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  DHC-6 (Twin Otter) Series Aeroplanes\n\n \n\n# AD/DHC-6/55 Fuel Boost Pumps - Inspection, Replacement, Modification\n\nApplicability: All DHC-6 models equipped with Airborne fuel boost pump model 1D2-17. Document:               1. De Havilland of Canada SB No. 6/449; and\n\n2. Airborne SL No. 26.\n\n# 2/84\n\n \n\nCompliance: 1. Initial inspection as detailed in Para 1 sub paras (A), (B) and (C) of Airborne SL No. 26 to be carried out before further flight after 31 January 1984, and thereafter, as applicable, repeat at daily intervals the inspection as detailed in Para 1 sub para\n\n(C) of Airborne SL No. 26 until modification embodied as detailed in Para 3 of Airborne SL No. 26.\n\n \n\n2. Replace those pumps as detailed in Para 1 sub para (D) of Airborne SL No. 26 before further flight after 31 January 1984.\n\n \n\nNote: Daily Inspection - For aircraft maintained in accordance with ANO 100.5.1 this inspection shall be entered on the maintenance release as maintenance required. The inspection may be performed by the pilot in command, in which case certification is not required. In all other cases certification may be made on the maintenance release. This inspection may also be performed and certified by any Licensed Aircraft Maintenance Engineer.\n\n \n\nBackground: The manufacturer has advised of the possibility of fuel leaks at the positive electrical terminal of the fuel boost pumps.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2518},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope focused solely on addressing the specific fuel leak defect in Airborne model 1D2-17 fuel boost pumps installed on DHC-6 aircraft. There is no evidence of expansion beyond this targeted airworthiness safety issue."},"complexity_factors":["Reliance on external technical documents (Service Bulletin 6/449 and Service Letter 26) for complete inspection and modification procedures","Time-critical 'before further flight' compliance deadline combined with ongoing daily recurring obligations","Dual compliance pathways offering either immediate replacement or temporary inspection regime until modification","Variable certification requirements contingent on maintenance program type (pilot-permitted vs engineer-certified)"],"plain_english_summary":"This mandatory safety directive affects owners, operators, LAMEs and certain pilots of DHC‑6 (Twin Otter) aircraft fitted with Airborne fuel boost pump model 1D2‑17. It requires immediate pump replacement or a detailed inspection before flying after 31 Jan 1984, with daily preflight checks until the permanent modification is fitted.\n\nThe action prevents fuel leaking from the pump’s positive electrical terminal near ignition sources, a serious fire/explosion hazard. Work must follow De Havilland SB 6/449 and Airborne SL No. 26."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification","history":"/api/acts/ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification/history","analysis":"/api/acts/ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification/analysis","conflicts":"/api/acts/ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification/conflicts","importantCases":"/api/acts/ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification/important-cases","documents":"/api/acts/ad-dhc-6-55-fuel-boost-pumps-inspection-replacement-modification/documents"}}