{"id":"F2006B06093","name":"AD/PC-12/30 - MLG Hydraulic Actuator Special Bolts","slug":"ad-pc-12-30-mlg-hydraulic-actuator-special-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":46827,"registerId":"commonwealth-F2006B06093-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\n![](image.001.png)  \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 CAR 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\nPilatus PC-12 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/PC-12/30 MLG Hydraulic Actuator Speci","sectionType":"part","heading":"AD/PC-12/30 MLG Hydraulic Actuator Special Bolts 13/2001","content":"# AD/PC-12/30 MLG Hydraulic Actuator Special Bolts 13/2001\n\nDM\n\nApplicability: Model PC-12 and PC-12/45 aircraft, serial numbers MSN 349, MSN 352, MSN 357, MSN 359, MSN 362 through MSN 365, MSN 367, MSN 369, MSN 371, MSN 375,\n\nMSN 377, MSN 380, MSN 384, MSN 385, MSN 388, MSN 390, MSN 391, MSN\n\n393, MSN 401, and MSN 409.\n\nRequirement: Inspect in accordance with Pilatus Aircraft Service Bulletin No. 30-012, dated 18 October 2001.\n\nNote: FOCA AD HB 2001-603 refers.\n\nCompliance: At the next scheduled 100 hour inspection or within 30 days after 21 November 2001, whichever occurs first.\n\nThis Airworthiness Directive becomes effective on 21 November 2001.\n\nBackground: It has been found on some PC-12/45 aircraft that special bolts connecting the hydraulic actuators to the main landing gear assemblies have the potential to fail during operation. Investigation revealed that the problem is caused by an improper cadmium plating process applied to the high strength steel part, which can cause hydrogen embrittlement.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 14 November 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 21 November 2001.","sortOrder":1}],"analysis":{"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 AD maintains its original narrow scope — addressing a specific manufacturing defect in specific aircraft serial numbers. There is no evidence of scope creep; it targets exactly the unsafe condition described in the background."},"complexity_factors":["Very short document (approximately 250 words)","Only 3 substantive sections: Applicability, Requirement, and Compliance","No defined terms section — all terms are plain English or standard aviation terminology","Single cross-reference to a Pilatus Service Bulletin and a Swiss aviation authority directive (FOCA AD HB 2001-603)","Simple conditional logic: 'whichever occurs first' is the only conditional element","No nested exceptions or sub-delegations"],"plain_english_summary":"This AD requires owners/operators of 21 specified Pilatus PC‑12/45 aircraft (MSN 349–409) to inspect the bolts attaching the hydraulic actuator to the main landing gear for hydrogen‑embrittlement from improper cadmium plating. Inspections must follow Pilatus Service Bulletin No. 30‑012 at the next 100‑hour check or within 30 days of 21 Nov 2001. The aim is to prevent bolt failure and potential landing‑gear collapse."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD is narrowly targeted to correct a specific manufacturing/processing defect (improper cadmium plating causing hydrogen embrittlement) on a defined set of aircraft serial numbers. It does not expand the regulatory scope beyond that original safety purpose: it mandates inspection per the manufacturer’s service bulletin within a short timeframe and does not introduce broader or additional regulatory obligations."},"complexity_factors":["Short, single-issue AD focused on one part (special bolts) and one failure mode (hydrogen embrittlement)","Applicability limited to a specific list of serial numbers (about 25–30 aircraft), requiring operators to check serial numbers","Requirement relies on an external technical document (Pilatus Service Bulletin No. 30-012) for procedural detail","Simple compliance timing with one conditional clause (next scheduled 100-hour inspection or within 30 days, whichever occurs first)","Cross-reference to a foreign authority notice (FOCA AD HB 2001-603) but no other nested exceptions or complex definitions","Single effective date and no multi-stage or recurring inspection schedule specified in the AD itself"],"plain_english_summary":"**What this instrument is and who it applies to**\n\n- This is an Airworthiness Directive (an official safety order) issued by the Civil Aviation Safety Authority (CASA) that applies only to certain Pilatus PC-12 and PC-12/45 aeroplanes listed by serial number (see \"Applicability\").\n\n**What it requires (mechanics of the rule)**\n\n- Operators of the listed aircraft must inspect the special bolts that attach the main landing gear hydraulic actuators in accordance with Pilatus Aircraft Service Bulletin No. 30-012 (dated 18 October 2001). (That service bulletin contains the detailed inspection steps and any corrective action.)\n- The inspection must be done at the next scheduled 100-hour inspection or within 30 days after 21 November 2001, whichever comes first. The AD became effective on 21 November 2001.\n- The AD refers to and is linked with a related foreign authority notice (FOCA AD HB 2001-603).\n\n**Why CASA ordered this (stated safety concern)**\n\n- Pilatus discovered that some of the high-strength steel special bolts had been cadmium plated using an improper process. That could cause hydrogen embrittlement (a material weakening process) and make the bolts liable to fail during operation. The AD’s explicit safety purpose is to find any affected bolts and take whatever corrective action the service bulletin prescribes.\n\n**Who pays, who decides, and how behaviour changes**\n\n- Who pays: Aircraft operators/owners bear the cost of performing the inspections and any remedial work (parts and labour) required by the service bulletin.\n- Who decides: The CASA delegate issued the AD under the aviation regulations; the practical inspection and repair decisions are carried out by operators and maintenance organisations following the Pilatus service bulletin.\n- Behaviour change required: Operators of the listed aircraft must schedule and complete the required inspections within the given timeframe and follow the service bulletin’s instructions if defects are found. Failure to comply would leave the aircraft non‑compliant with the AD and therefore not meeting airworthiness requirements.\n\n**Implementation and trade-offs (testing the stated purpose against costs and risks)**\n\n- The AD delegates the technical method to Pilatus’s Service Bulletin rather than prescribing inspection steps in the AD itself. That reduces duplication but makes compliance dependent on a separate document (operators must obtain and follow that document).\n- Cost and operational impact are concentrated on the small set of affected serial-number aircraft; costs are direct (inspection labour, possible replacement of bolts) and immediate (must be done at next 100‑hour or within 30 days). For operators not on the list, there is no action required.\n- There is a modest compliance burden on maintenance providers to prioritise and schedule the mandated inspections inside a short window, which can disrupt planned maintenance cycles if the next 100‑hour check is later than 30 days.\n- The AD reduces the risk of in‑service bolt failure, trading that reduced safety risk for the direct cost and downtime of inspections/repairs. The AD relies on a material-failure diagnosis (hydrogen embrittlement) as the causal mechanism and seeks to correct it by inspection and corrective action.\n- Because the AD references a foreign authority notice and a manufacturer service bulletin, it centralises technical content in those sources; that creates dependency on external documents for exact procedures and may require operators to consult multiple documents to confirm compliance.\n\n**Concentrated benefits and diffuse costs**\n\n- Benefits (reduced risk of bolt failure) accrue primarily to the operators/occupants of the affected aircraft and to aviation safety broadly. Costs (inspection and repair) are concentrated on those same aircraft owners/operators.\n\n**Practical note**\n\n- To comply, an operator should obtain Pilatus Service Bulletin No. 30-012 (18 Oct 2001), schedule the inspection by an authorised maintenance organisation within the stated timeframe, and retain records showing the inspection and any corrective action taken to demonstrate compliance with the AD.\n\n(References: Applicability; Requirement; Compliance; Background sections of the AD.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pc-12-30-mlg-hydraulic-actuator-special-bolts","history":"/api/acts/ad-pc-12-30-mlg-hydraulic-actuator-special-bolts/history","analysis":"/api/acts/ad-pc-12-30-mlg-hydraulic-actuator-special-bolts/analysis","conflicts":"/api/acts/ad-pc-12-30-mlg-hydraulic-actuator-special-bolts/conflicts","importantCases":"/api/acts/ad-pc-12-30-mlg-hydraulic-actuator-special-bolts/important-cases","documents":"/api/acts/ad-pc-12-30-mlg-hydraulic-actuator-special-bolts/documents"}}