{"id":"F2005L03556","name":"AD/B737/259 - Fail-Safe Straps of the Nose Cowl Engine Inlet Attach Ring","slug":"ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39082,"registerId":"commonwealth-F2005L03556-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/259 | Fail-Safe Straps of the Nose CowlEngine Inlet Attach Ring | 13/2005 |\n| ----------- | --------------------------------------------------------- | ------- |\n\n| Applicability: | Model 737-200 and -200C series aircraft, equipped with dB Partners Hush Kit having attach ring, part number 65ND-54301-1, installed in accordance with Supplemental Type Certificate (STC) SA5730NM.                                                                                                                                                                                                                                                                                                                                                 |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with FAA AD 96-04-03 Amdt 39-9514.Note: Nordam Service Bulletins SB 71-03, SB 71-03 Revision 1, and SB 71-04 Revision 1, or later FAA approved revisions, refer.                                                                                                                                                                                                                                                                                                                                                                |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of22 December 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n|                | This Airworthiness Directive becomes effective on 22 December 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n| Background:    | The FAA received reports of failure of reworked turbine blades, and subsequent failure of engine inlet attach ring. This Directive requires repetitive inspections to detect cracking of the attach ring of the nose cowl, until replacement with an improved attach ring that eliminates the need for repetitive inspections. The actions specified by this Directive are intended to prevent cracking of the attach ring of the nose cowl, which could result in separation of the nose cowl from the engine following failure of a turbine blade. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n10 November 2005","sortOrder":0},{"sectionNumber":"AD/B737/259","sectionType":"part","heading":"AD/B737/259","content":"## AD/B737/259","sortOrder":1},{"sectionNumber":"Fail-Safe Straps of the Nose CowlEngine ","sectionType":"part","heading":"Fail-Safe Straps of the Nose CowlEngine Inlet Attach Ring","content":"## Fail-Safe Straps of the Nose Cowl  \nEngine Inlet Attach Ring","sortOrder":2},{"sectionNumber":"13/2005","sectionType":"part","heading":"13/2005","content":"## 13/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This Directive adopts the FAA AD requirements for repetitive inspections and replacement and applies specifically to 737-200/-200C aeroplanes with the specified dB Partners attach ring installed under STC SA5730NM. The text does not indicate an expansion or narrowing of scope beyond the FAA AD it references."},"complexity_factors":["Cross-reference to FAA AD 96-04-03 Amdt 39-9514 rather than restating procedures (Requirement)","Applicability limited to aircraft with Hush Kit attach ring P/N 65ND-54301-1 installed under STC SA5730NM — narrow technical scope (Applicability)","Repetitive inspection requirement until replacement with an improved part creates ongoing operational burden (Background/Requirement)","References to external Nordam Service Bulletins and any later FAA-approved revisions add dependency on external documents (Requirement Note)","Revised effective date and mandatory compliance timeline add scheduling/administration tasks for operators (Compliance)","Technical inspection methods, criteria for cracking, and replacement parts are defined in external FAA/service documents, increasing implementation reliance on other sources (Requirement/Background)","Costs and downtime for owners/operators from inspections and part replacement are implicit but material to compliance (Applicability/Background)","Delegation of compliance actions to operators and maintenance organisations requires judgements about inspection intervals and replacement timing under the referenced FAA AD (Requirement)"],"plain_english_summary":"This AD requires operators of Boeing 737‑200 and ‑200C aeroplanes fitted with the dB Partners Hush Kit attach ring (P/N 65ND‑54301‑1, installed under STC SA5730NM) to carry out repetitive inspections in accordance with FAA AD 96‑04‑03 and to replace the attach ring with an improved part when available. It aims to detect cracking that could lead to nose‑cowl separation after turbine blade failure.\n\nOwners/operators pay for inspections and replacement, must follow the FAA AD and referenced Nordam service bulletins, and comply from 22 December 2005."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific mechanical failure mode in a specific aircraft configuration. It has not expanded beyond its original safety purpose."},"complexity_factors":["Short, single-purpose instrument (approximately 250 words)","Only 1 defined applicability criterion (specific STC and part number)","Incorporates external documents by reference (FAA AD 96-04-03, Nordam Service Bulletins) rather than reproducing requirements inline","Simple conditional structure: inspect repeatedly → replace → stop inspecting","No nested exceptions or elaborate compliance calculations","Cross-references are limited to one primary external document and two service bulletins"],"plain_english_summary":"This CASA Airworthiness Directive applies to Boeing 737-200/200C aircraft fitted with the dB Partners hush kit (STC SA5730NM). It mandates repeated inspections of the nose cowl engine inlet attach ring, continuing until the ring is replaced with an improved part per FAA AD 96-04-03 and Nordam service bulletins.\n\nIt responds to failures of reworked turbine blades that can crack the ring and allow the nose cowl to detach in flight. Compliance deadline: 22 December 2005."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring","history":"/api/acts/ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring/history","analysis":"/api/acts/ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring/analysis","conflicts":"/api/acts/ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring/conflicts","importantCases":"/api/acts/ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring/important-cases","documents":"/api/acts/ad-b737-259-fail-safe-straps-of-the-nose-cowl-engine-inlet-attach-ring/documents"}}