{"id":"F2017L01388","name":"AD/DHC-8/11 Amdt 2 - Engine Cowl Door Retention and Pressure Relief","slug":"ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":144203,"registerId":"commonwealth-F2017L01388-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bombardier DHC-8 Series Aeroplanes","sectionType":"part","heading":"Bombardier DHC-8 Series Aeroplanes","content":"# Bombardier DHC-8 Series Aeroplanes\n\n| AD/DHC-8/11 Amdt 2 | Engine Cowl Door Retentionand Pressure Relief | 21/2017 |\n| ------------------ | --------------------------------------------- | ------- |\n\n| Applicability: | Bombardier DHC-8 Model 100 series, serial numbers 3 through 193.                                                                                                                                                                                                                                                                                                                                        |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Modify both engine cowlings in accordance with Bombardier Service Bulletin (SB) 8-71-13, as in force from time to time.Note 1: Canadian AD CF-89-15R1 refers.Note 2: The words “as in force from time to time” require compliance with the most recent version of the SB.                                                                                                                               |\n| Compliance:    | Within 30 days after the commencement date of this AD, unless previously accomplished.Note 3: Previous compliance with the requirement in AD/DHC-8/11 Amdt 1 constitutes compliance with the requirement in this AD.                                                                                                                                                                                    |\n|                | This AD commences on 3 November 2017.                                                                                                                                                                                                                                                                                                                                                                   |\n| Background:    | There have been instances of loss of engine cowl doors during engine fires. That door loss has rendered the fire extinguishing system ineffective.Amendment 1 of this AD was issued to reflect Revision C of the Requirement Document (Bombardier SB 8-71-13).Amendment 2 is issued to align the AD applicability with that of the Canadian AD and to reference the latest revision of the Canadian AD. |\n\n![](image.001.png)\n\nBen Wilson  \nDelegate of the Civil Aviation Safety Authority\n\n18 October 2017","sortOrder":0},{"sectionNumber":"AD/DHC-8/11 Amdt 2","sectionType":"part","heading":"AD/DHC-8/11 Amdt 2","content":"## AD/DHC-8/11 Amdt 2","sortOrder":1},{"sectionNumber":"Engine Cowl Door Retentionand Pressure R","sectionType":"part","heading":"Engine Cowl Door Retentionand Pressure Relief","content":"## Engine Cowl Door Retention  \nand Pressure Relief","sortOrder":2},{"sectionNumber":"21/2017","sectionType":"part","heading":"21/2017","content":"## 21/2017","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is Amendment 2 of an existing Airworthiness Directive. The amendments have remained tightly focused on the original safety issue (engine cowl door retention during fires). Amendment 1 updated the technical reference to Revision C of the Service Bulletin; Amendment 2 merely aligned the applicability with the Canadian AD and updated the Canadian AD reference. The scope has not expanded beyond the specific technical modification required for fire safety."},"complexity_factors":["Very short document (approximately 250 words)","Only 1 defined applicability criterion (specific aircraft model and serial number range)","Single compliance requirement with reference to external technical document (Service Bulletin)","Simple temporal compliance condition (30 days from commencement)","No nested exceptions or conditional logic — only a straightforward exemption for aircraft already modified under previous AD version","Minimal cross-referencing (only to Canadian AD CF-89-15R1 and manufacturer Service Bulletin)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Bombardier DHC‑8 Model 100 aircraft (serials 3–193) to modify both engine cowlings per Bombardier Service Bulletin 8‑71‑13 (as updated) within 30 days of 3 Nov 2017.  \n\nThe change prevents engine cowl doors detaching during engine fires so fire‑extinguishing systems remain effective, addressing a critical safety risk."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 2 alters the AD’s scope to match the Canadian AD by changing applicability and referencing the latest revision of the Canadian AD and the Bombardier SB (Background). Practically, this aligns affected serial numbers and requires compliance with the most recent service bulletin version rather than a fixed edition."},"complexity_factors":["Narrow applicability to DHC-8 Model 100 series, serial numbers 3–193 (Applicability).","Mandatory modification of both engine cowlings to meet a service bulletin (Requirement) — a defined maintenance action rather than a performance standard.","Reliance on an external document with the phrase “as in force from time to time” requires operators to track and comply with the latest SB revision (Requirement).","Short compliance window: 30 days from AD commencement (Compliance), increasing scheduling and logistics pressure on operators.","Acceptance of prior compliance under AD/DHC-8/11 Amdt 1 reduces duplicative work but requires record verification (Compliance).","Safety-critical context: door loss during engine fires affects fire-extinguishing effectiveness (Background), meaning non-compliance has operational safety consequences.","Costs (parts, labour, downtime) and enforcement burden fall on aircraft operators and maintenance organisations (Requirement, Compliance)."],"plain_english_summary":"This Airworthiness Directive requires operators of Bombardier DHC-8 Model 100 series aircraft (serial numbers 3–193) to modify both engine cowlings to improve cowl-door retention and pressure relief, following Bombardier Service Bulletin 8-71-13 (Requirement). Compliance is mandatory within 30 days of the AD’s commencement (3 November 2017); previous compliance under AD/DHC-8/11 Amdt 1 is accepted. The rule places the cost and work on aircraft operators and their maintenance providers and requires them to use the most recent SB revision (Requirement, Compliance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief","history":"/api/acts/ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief/history","analysis":"/api/acts/ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief/analysis","conflicts":"/api/acts/ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief/conflicts","importantCases":"/api/acts/ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief/important-cases","documents":"/api/acts/ad-dhc-8-11-amdt-2-engine-cowl-door-retention-and-pressure-relief/documents"}}