{"id":"F2005L01305","name":"AD/JT8D/21 Amdt 1 - High Pressure Compressor Spacers","slug":"ad-jt8d-21-amdt-1-high-pressure-compressor-spacers","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":35045,"registerId":"commonwealth-F2005L01305-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Pratt and Whitney Turbine Engines - JT8D","sectionType":"division","heading":"Pratt and Whitney Turbine Engines - JT8D Series","content":"### Pratt and Whitney Turbine Engines - JT8D Series\n\n| AD/JT8D/21 Amdt 1 | High Pressure Compressor Spacers | 7/2005 |\n| ----------------- | -------------------------------- | ------ |\n\n| Applicability: | Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17,-17A, -17R, and -17AR turbofan engines.                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | To prevent crack propagation and subsequent high pressure compressor (HPC) removable sleeve spacer rupture, perform a one time, eddy current inspection of HPC removable sleeve spacers stages 7-8, 8-9, and 9-10 for cracks, and replace all stages of HPC removable sleeve spacers with the respective HPC integral sleeve spacers, in accordance with the requirements of FAA Airworthiness Directive 86-08-04 R1.Note: FAA AD 86-08-04 R1 Amendment 39-5424 refers.                                                                             |\n| Compliance:    | Unless previously accomplished, as per compliance schedule of the FAA AD86-08-04 R1.                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n|                | This Amendment becomes effective on 7 July 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Background:    | There have been reports of crack initiation, crack propagation and subsequent high pressure compressor (HPC) removable sleeve spacer rupture, resulting in engine failure. The inspection requirements of this AD are aimed at detection of cracks and prevention of resultant engine failure.The current amendment deletes reference to the manufacturer’s document and refers to the FAA AD as part of the harmonisation with the engine certificating Authority requirements.Original issue of this Directive became effective on 21 April 1986. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n25 May 2005","sortOrder":0},{"sectionNumber":"AD/JT8D/21 Amdt 1","sectionType":"part","heading":"AD/JT8D/21 Amdt 1","content":"## AD/JT8D/21 Amdt 1","sortOrder":1},{"sectionNumber":"High Pressure Compressor Spacers","sectionType":"part","heading":"High Pressure Compressor Spacers","content":"## High Pressure Compressor Spacers","sortOrder":2},{"sectionNumber":"7/2005","sectionType":"part","heading":"7/2005","content":"## 7/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment does not materially change the directive's safety scope or applicability. It retains the one‑time inspection and replacement requirements but deletes the manufacturer‑document reference and instead refers to FAA AD 86‑08‑04 R1 to harmonise procedures and compliance timing (Background; Requirement; Compliance)."},"complexity_factors":["Technical NDT requirement: eddy‑current inspection of specific HPC spacer stages (7–8, 8–9, 9–10) increases inspection skill and equipment needs","Multiple engine variants covered (long applicability list) requiring record checks for affected fleets","Mandated part replacement (removable → integral sleeve spacers) imposes parts, labour and aircraft downtime costs","Cross‑reference to FAA AD 86‑08‑04 R1 places compliance timing and procedures outside the local instrument text (regulatory dependency)","One‑time action limits recurring burden but concentrates immediate logistics and cost impact","Amendment deletes a manufacturer document reference and harmonises with FAA guidance, reducing local procedural discretion (Background)"],"plain_english_summary":"Mechanically, this directive requires operators of specified Pratt & Whitney JT8D engine models to do a one‑time eddy‑current inspection of high‑pressure compressor removable sleeve spacers (stages 7–8, 8–9, 9–10) and to replace removable spacers with integral sleeve spacers where cracks are found, following FAA AD 86‑08‑04 R1 (Requirement; Compliance). Operators pay for inspections, parts and downtime; CASA enforces the FAA‑timed compliance. The amendment removes a manufacturer‑document reference to harmonise with the FAA (Background)."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope of the 1986 directive. The change is purely administrative — replacing a reference to the manufacturer's document with a reference to the FAA Airworthiness Directive to achieve regulatory harmonisation. The safety objective (preventing HPC spacer rupture), the affected engine models, and the required actions remain unchanged from the original intent."},"complexity_factors":["Single, clearly defined mechanical issue (cracked compressor spacers)","Straightforward two-step compliance: inspect once, then replace","Only 17 engine variants listed, all within one engine family","Heavy reliance on external document (FAA AD 86-08-04 R1) for actual technical procedures — the Australian directive acts as a 'pointer' rather than containing detailed instructions","No nested exceptions or conditional logic — compliance is mandatory unless already accomplished","Minimal defined terms (only standard aviation abbreviations like HPC)","Short document (approximately 250 words of substantive content)"],"plain_english_summary":"This is an **Australian Airworthiness Directive** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires specific maintenance actions on aircraft engines.\n\n**What it does:**\nOrders owners and operators of certain Pratt & Whitney JT8D jet engines to inspect and replace specific parts in the **high pressure compressor** (a critical section of the engine that compresses air before combustion).\n\n**The specific problem:**\nThe **removable sleeve spacers** in stages 7-10 of the compressor can develop cracks. If these cracks spread, the spacers can rupture and cause **complete engine failure**.\n\n**What must be done:**\n- A **one-time eddy current inspection** (a non-destructive testing method using electromagnetic fields to detect surface cracks) of specific spacer stages (7-8, 8-9, and 9-10)\n- **Replacement** of all removable sleeve spacers with newer **integral sleeve spacers** (a redesigned, more robust part)\n\n**Who it affects:**\nAnyone operating aircraft with Pratt & Whitney JT8D engines, specifically models: -1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR variants. These engines are commonly used on older Boeing 727 and 737-100/200 aircraft, as well as McDonnell Douglas DC-9 and MD-80 series aircraft.\n\n**Why this amendment matters:**\nThis is **Amendment 1** to an existing directive originally issued in 1986. The change **harmonises Australian requirements with the US Federal Aviation Administration (FAA)** by referencing the FAA's directive directly rather than the manufacturer's document. This ensures Australian operators follow the same safety standards as the country where the engines were originally certified.\n\n**Compliance deadline:**\nOperators must complete the work according to the schedule in the referenced FAA directive, unless already done."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jt8d-21-amdt-1-high-pressure-compressor-spacers","history":"/api/acts/ad-jt8d-21-amdt-1-high-pressure-compressor-spacers/history","analysis":"/api/acts/ad-jt8d-21-amdt-1-high-pressure-compressor-spacers/analysis","conflicts":"/api/acts/ad-jt8d-21-amdt-1-high-pressure-compressor-spacers/conflicts","importantCases":"/api/acts/ad-jt8d-21-amdt-1-high-pressure-compressor-spacers/important-cases","documents":"/api/acts/ad-jt8d-21-amdt-1-high-pressure-compressor-spacers/documents"}}