{"id":"F2006B08665","name":"AD/CRESCO/6 - Fin Forward Attachment Fitting","slug":"ad-cresco-6-fin-forward-attachment-fitting","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51756,"registerId":"commonwealth-F2006B08665-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nPacific Aerospace Corporation Cresco Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/CRESCO/6 Fin Forward Attachment Fitti","sectionType":"part","heading":"AD/CRESCO/6 Fin Forward Attachment Fitting 7/2004","content":"# AD/CRESCO/6 Fin Forward Attachment Fitting 7/2004\n\nDM\n\nApplicability: Model 08-600 series aircraft with aluminium fin forward attachment fitting part number 243017-2 installed.\n\nRequirement: 1. Inspect in accordance with the Accomplishment Instructions of Pacific Aerospace Corporation Mandatory Service Bulletin (MSB) PACSB/CR/037. Additionally, inspect adjacent structure for corrosion or cracking and replace or repair as necessary.\n\nIf the attachment fitting is found cracked or corroded, replace the fitting before further flight following inspection.\n\n2. Replace aluminium attachment fitting part number 243017-2 with steel attachment fitting part number 243017-3 in accordance with the Accomplishment Instructions of MSB PACSB/CR/037.\n\nNote: NZ CAA AD DCA/CRESCO/7 refers.\n\nCompliance: 1. Within 50 hours time in service after 12 May 2004, and thereafter at intervals not to exceed 150 hours time in service; until accomplishment of Requirement 2 .\n\n2. Upon the accumulation of 3,000 hours total time in service or within 150 hours time in service after 12 May 2004, whichever occurs later.\n\nThis Airworthiness Directive becomes effective on 12 May 2004.\n\nBackground: The manufacturer received a report of failure of an aluminium fin forward attachment fitting.\n\n![Signature of David Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Villiers\n\n![](image.001.png)Delegate of the Civil Aviation Safety Authority 5 May 2004","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD remains narrowly focused on a single unsafe condition: failure risk of an aluminium fin forward attachment fitting on Cresco 08-600 aircraft. The measures (repeated inspections until mandatory replacement with a steel fitting) are directly tied to that problem. There is no expansion of scope beyond addressing the specific fitting failure; the cross-reference to the manufacturer’s Service Bulletin and the NZ CAA AD are procedural and cooperative, not scope-expanding."},"complexity_factors":["Short, single-aircraft-type AD with two primary requirements (inspection then replacement).","Two specific part numbers to identify (243017-2 aluminium; 243017-3 steel).","Time-based compliance logic including an initial short-window inspection (within 50 hours), recurring inspections (every 150 hours), and a replacement triggered by total time-in-service threshold (3,000 hours) or a short deadline (within 150 hours after 12 May 2004), with a 'whichever occurs later' clause.","Cross-reference to an external document for procedural detail (Mandatory Service Bulletin PACSB/CR/037).","Reference to another regulator's AD (NZ CAA AD DCA/CRESCO/7) but no additional substantive branching conditions."],"plain_english_summary":"**What this directive does (mechanically)**\n\n- This is an Airworthiness Directive (AD) that applies to Pacific Aerospace Corporation Cresco Model 08-600 aeroplanes that have an aluminium fin forward attachment fitting fitted with part number 243017-2 (Applicability).\n- It requires two things (Requirement):\n  - 1) Repeated inspections of that aluminium fitting and the adjacent structure for cracking or corrosion, carried out in accordance with the manufacturer’s Accomplishment Instructions in Mandatory Service Bulletin PACSB/CR/037. If cracking or corrosion is found, the fitting must be replaced before the aircraft flies again. (Requirement 1)\n  - 2) Permanent replacement of the aluminium fitting (p/n 243017-2) with a steel fitting (p/n 243017-3) in accordance with the same Service Bulletin. (Requirement 2)\n- Timing for compliance (Compliance):\n  - Inspections: do an initial inspection within 50 hours time-in-service after 12 May 2004, and then repeat inspections at intervals not exceeding 150 hours time-in-service until the aluminium fitting has been replaced. (Compliance 1)\n  - Replacement: install the steel fitting either when the aircraft reaches 3,000 hours total time-in-service or within 150 hours time-in-service after 12 May 2004, whichever happens later. (Compliance 2)\n- Why it was issued (Background): the manufacturer reported a failure of an aluminium fin forward attachment fitting; the AD is intended to correct that unsafe condition.\n\n**Who this affects**\n\n- Aircraft owners, operators, and maintenance organisations that operate or work on Pacific Aerospace Cresco Model 08-600 aircraft with the aluminium fin forward attachment fitting p/n 243017-2 installed.\n- Maintenance personnel who must carry out the inspections and the replacement in accordance with the manufacturer’s Service Bulletin.\n\n**Why it matters (practical effects and decision points)**\n\n- Safety mechanism: The AD forces early detection of cracking/corrosion (via repeated inspections) and eliminates the aluminium part by mandating a steel replacement to prevent future failures (Requirements 1 & 2).\n- Who pays: owners/operators pay for the inspections, any repairs to adjacent structure, and the replacement fitting and installation.\n- Who decides and acts: approved maintenance organisations or authorised maintenance personnel must perform the inspections and replacement in line with the manufacturer’s Accomplishment Instructions (Requirement, Compliance).\n- Behaviour changes: operators must schedule recurring inspections until the fitting is replaced and schedule the replacement at the specified time threshold, which will create maintenance downtime and parts procurement needs.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: inspection labour and downtime, cost of the steel fitting and installation, and any repair/replacement of adjacent corroded or cracked structure found during inspection (Requirement 1).\n- Timing trade-off: the AD allows continued operation under a regime of frequent inspections until the fitting is replaced, which spreads costs over time but requires ongoing inspection burden (Compliance 1). It also sets a firm deadline for replacement (3,000 hours TIS or within 150 hours after 12 May 2004) to eliminate long-term inspection burden (Compliance 2).\n- Incentives: owners may accelerate replacement to reduce inspection frequency and operational risk; conversely, those with limited resources may opt to rely on inspections until the replacement deadline, accepting ongoing inspection cost and residual risk until the steel fitting is installed.\n\n**Implementation risks and compliance burden**\n\n- Reliance on external documents: the AD mandates actions “in accordance with the Accomplishment Instructions” of the manufacturer’s MSB PACSB/CR/037. Access to and correct interpretation of that Service Bulletin is necessary to comply (Requirement). That creates administrative dependency on the MSB for procedural detail.\n- Parts availability: supply or lead time for the steel fittings (p/n 243017-3) can affect the ability to meet the replacement deadline and may extend aircraft downtime.\n- Inspection effectiveness: detecting early-stage corrosion/cracking can be subjective and depends on inspection technique and inspector skill; missed defects risk in-service failure, while conservative findings increase repair/replacement costs.\n- Record-keeping and enforcement: operators must track hours-in-service and inspection intervals to meet the specific deadlines (Compliance).\n\n**Market and operational effects**\n\n- Operators face increased maintenance costs and scheduling constraints; small operators may be disproportionately affected because the directive targets a specific part on a narrow fleet.\n- Secondary effects may include reduced resale value for aircraft with the aluminium part still installed, or decisions to retire aircraft rather than invest in replacement if parts/maintenance costs are high.\n\n**References to the AD text**\n\n- Applicability: Model 08-600 with aluminium fitting p/n 243017-2.\n- Requirement 1 & 2: inspection obligation and mandatory replacement with steel p/n 243017-3 (MSB PACSB/CR/037).\n- Compliance: initial inspection within 50 hours after 12 May 2004, repeat every 150 hours until replacement; replacement at 3,000 hours TIS or within 150 hours after 12 May 2004, whichever later.\n- Background: manufacturer reported a failure of the aluminium fitting.\n\n(Notes: The AD also refers to a New Zealand CAA AD DCA/CRESCO/7 for related material; that cross-reference does not change the specific requirements above.)"},"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":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope — addressing a specific unsafe condition in a specific aircraft part. ADs are inherently limited in scope by design, targeting particular safety defects rather than broad regulatory schemes."},"complexity_factors":["Single, clearly defined applicability (one aircraft model series with specific part number)","Two straightforward requirements with clear sequential logic (inspect until replaced)","Simple compliance timeline with two alternative triggers (hours-based deadlines)","Only one cross-reference (to New Zealand aviation authority's equivalent directive)","No nested definitions or conditional exceptions","Total length: approximately 250 words"],"plain_english_summary":"Owners/operators of Pacific Aerospace Cresco 08-600 series aircraft must inspect and replace the aluminium fin forward attachment fitting (P/N 243017‑2) after a reported in-service failure. The order mandates an initial inspection within 50 flight hours (then every 150 hours until replacement), immediate replacement if cracks/corrosion are found, and permanent replacement with the steel fitting (P/N 243017‑3) by 3,000 total hours or within 150 flight hours—non‑compliance grounds aircraft grounded."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cresco-6-fin-forward-attachment-fitting","history":"/api/acts/ad-cresco-6-fin-forward-attachment-fitting/history","analysis":"/api/acts/ad-cresco-6-fin-forward-attachment-fitting/analysis","conflicts":"/api/acts/ad-cresco-6-fin-forward-attachment-fitting/conflicts","importantCases":"/api/acts/ad-cresco-6-fin-forward-attachment-fitting/important-cases","documents":"/api/acts/ad-cresco-6-fin-forward-attachment-fitting/documents"}}