{"id":"F2006B11022","name":"AD/JT9D/29 Amdt 2 - Turbine Exhaust Case","slug":"ad-jt9d-29-amdt-2-turbine-exhaust-case","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56628,"registerId":"commonwealth-F2006B11022-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JT9D/29 Amdt 2 - Turbine Exhaust Case","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPratt and Whitney Turbine Engines \\- JT9D Series\n\nAD/JT9D/29\n\nAmdt 2\n\n  \nTurbine Exhaust Case 2/98\n\nApplicability: Pratt and Whitney JT9D series engines.\n\nRequirement: 1. Install an improved turbine exhaust case in accordance with the technical requirement of FAA AD 96-25-10, or\n\n2. Install an improved turbine exhaust case in accordance with Pratt and Whitney Service Bulletin JT9D-7R4-72-534 Revision 1.\n\nNote: Pratt and Whitney Service Bulletin JT9D-7R4-72-534 Revision 1, Paragraph\n\n1.D advises compliance with SB JT9D-7R4-72-534 has been approved by the FAA as an alternative means of compliance for FAA AD 96-25-10.\n\nCompliance: Unless previously accomplished, as detailed in the requirement document with an effective date of 30 January 1998.\n\nThis amendment becomes effective on 29 January 1998.\n\nBackground: This Directive is issued on advice from the FAA of a significant number of uncontained engines failures since 1972. The improved turbine exhaust case features enhanced debris containment in the event of an engine failure.\n\nThis amendment adds an alternative means of compliance.\n\nAmendment 1 corrected the FAA reference in the requirement statement and became effective on 19 June 1997.\n\nAmendment 1 of this airworthiness directive became effective on 19 June 1997. The original issue of this airworthiness directive became effective on 22 May 1997.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of requiring improved turbine exhaust cases for safety. The only change is adding an alternative compliance method (the Pratt & Whitney service bulletin), which does not expand the substantive requirements or applicability."},"complexity_factors":["Single technical requirement with two alternative compliance paths","Only 1 defined term implicitly referenced (FAA AD reference)","No nested conditional logic or exceptions","Short document (approximately 200 words)","Clear cross-reference structure (FAA AD to manufacturer service bulletin)","Straightforward compliance deadline structure"],"plain_english_summary":"This safety order requires operators of Pratt & Whitney JT9D engines in Australia to install an improved turbine exhaust case to contain debris from engine failures, a risk linked to multiple JT9D incidents since 1972.  \n\nIt maintains the same safety standard but adds flexibility: compliance can be achieved by following either the FAA airworthiness directive or Pratt & Whitney’s service bulletin."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"This amendment adds an alternative means of compliance: operators may comply either with FAA AD 96-25-10 or with Pratt & Whitney Service Bulletin JT9D-7R4-72-534 Revision 1 (the SB is noted as FAA‑approved in paragraph 1.D). The core requirement—installation of an improved turbine exhaust case on JT9D engines—remains, but the available compliance route was broadened."},"complexity_factors":["Technical retrofit: replacement of a turbine exhaust case on JT9D engines (requires specialised parts and maintenance capability).","Dual compliance paths: cross-reference to FAA AD 96-25-10 and Pratt & Whitney Service Bulletin JT9D-7R4-72-534 Revision 1 (operators must determine which document they follow).","Approval note: Service Bulletin paragraph 1.D states FAA approval as an alternative means of compliance, creating dependency on an external regulator's endorsement.","Timing constraint: compliance tied to a requirement document with an effective date of 30 January 1998, requiring program scheduling.","Applicability scope: applies to the entire Pratt & Whitney JT9D series (broad operator base affected).","Amendment history: multiple amendments and corrected references raise record‑keeping and verification needs for compliance status."],"plain_english_summary":"Requires installation of an improved turbine exhaust case on Pratt & Whitney JT9D engines, either under FAA AD 96-25-10 or Pratt & Whitney Service Bulletin JT9D‑7R4‑72‑534 Rev 1. The change, issued after reports of uncontained engine failures, is intended to improve debris containment.\n\nAircraft operators are responsible for arranging and paying for the modification and must comply by the requirement document with an effective date of 30 January 1998."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt9d-29-amdt-2-turbine-exhaust-case","history":"/api/acts/ad-jt9d-29-amdt-2-turbine-exhaust-case/history","analysis":"/api/acts/ad-jt9d-29-amdt-2-turbine-exhaust-case/analysis","conflicts":"/api/acts/ad-jt9d-29-amdt-2-turbine-exhaust-case/conflicts","importantCases":"/api/acts/ad-jt9d-29-amdt-2-turbine-exhaust-case/important-cases","documents":"/api/acts/ad-jt9d-29-amdt-2-turbine-exhaust-case/documents"}}