{"id":"F2007L00111","name":"AD/CRESCO/10 - MLG Axles","slug":"ad-cresco-10-mlg-axles","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68192,"registerId":"commonwealth-F2007L00111-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Pacific Aerospace Corporation Cresco Ser","sectionType":"division","heading":"Pacific Aerospace Corporation Cresco Series Aeroplanes","content":"### Pacific Aerospace Corporation Cresco Series Aeroplanes\n\n| AD/CRESCO/10 | MLG Axles | 2/2007 |\n| ------------ | --------- | ------ |\n\n| Applicability: | All Cresco 08-600 aircraft on restricted category agricultural operations fitted with main landing gear (MLG) axles part number (P/N) 08-40021-1, 08-40021-2, or08-40021-3.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. For aircraft fitted with MLG axles P/N 08-40021-1 or P/N 08-40021-2.Disassemble the MLG wheel assembly, clean the axles and remove as required, in accordance with Chapter 32 of Pacific Aerospace Corporation (PAC) Cresco 08-600 Maintenance Manual (MM).a. Inspect the axles for security in accordance with the maintenance schedule in Chapter 05-10-00, page 615 of PAC Cresco 08-600 MM.b. Visually inspect axles for cracks, paying particular attention to the shoulder radii, as detailed in Table 1 of PACSL/CR/06-1 Revision 1 and the instructions in PAC Cresco 08-600 MM Supplement PAC/CR/0442.c. Inspect the MLG axles for cracks using an approved direct or indirect magnetic particle inspection method that is equivalent to ASTM Standard No. E-1444, and the maintenance schedule in Chapter 05-10-00 page 601, and the instructions in Chapter 32-10-00 page 602, paragraph c, of PAC Cresco 08-600 MM and PACSL/CR/06-1.Replace cracked axles before further flight.Re-assemble and lubricate MLG axles in accordance with Chapters 32 and 12 of PAC Cresco 08-600 MM.2. For aircraft fitted with MLG axles P/N 08-40021-3.Disassemble the MLG wheel assembly, clean the axles and remove as required, in accordance with Chapter 32 of PAC Cresco 08-600 (MM).a. Inspect the axles for security in accordance with the maintenance schedule in Chapter 05-10-00, page 615 of PAC Cresco 08-600 MM.b. Visually inspect axles for cracks, paying particular attention to the shoulder radii, as detailed in Table 2 of PACSL/CR/06-1 Revision 1 and the instructions in PAC Cresco 08-600 MM Supplement PAC/CR/0443. |\n\n|             | c. Inspect the MLG axles for cracks using dye penetrant inspection method in accordance with the maintenance schedule in Chapter 05-10-00 page 601, and the instructions in Chapter 32-10-00 page 602, paragraph c, of PAC Cresco 08-600 MM and PACSL/CR/06-1.Replace cracked axles before further flight.Re-assemble and lubricate MLG axles in accordance with Chapters 32 and 12 of PAC Cresco 08-600 MM.Note 1: MOD PAC/CR/0442 introduces axles P/N 08-40021-2 as a replacement for axles P/N 08-40021-1, which are no longer available.Note 2: MOD PAC/CR/0443 introduces axles P/N 08-08-40021-3, which have a dye penetrant inspection requirement.Note 3: Torque Plates P/N 08-40055-2 and 08-40056-2 are to be fitted when MLG axles P/N 08-40021-2 or 08-40021-3 are installed.Note 4: ASTM Standard No. E-1444 establishes minimum requirements for magnetic particle inspection examination used for the detection of surface or slightly subsurface discontinuities in ferromagnetic material.Note 5: NZ CAA AD DCA/CRESCO/10 refers.                                                                                                                                                             |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1.a. and 2.a. Within 150 hours time in service after 15 February 2007 or before the accumulation of 1,500 landings on the MLG axles, whichever occurs first; unless already accomplished within the last 150 hours time in service. Thereafter inspect at intervals not to exceed 150 hours time in service or before the accumulation of 1,500 landings on the axles, whichever occurs first.1.b. and 2.b. Within 150 hours time in service after 15 February 2007 or before the accumulation of 1,500 landings on the MLG axles, whichever occurs first; unless already accomplished within the last 300 hours time in service. Thereafter inspect at intervals not to exceed 300 hours time in service or before the accumulation of 3,000 landings on the axles, whichever occurs first.1.c. For aircraft fitted with MLG axles P/N 08-40021-1:Before exceeding 500 hours time in service or before the accumulation of 6,000 landings on the MLG axles, or within 150 hours time in service after 15 February 2007, whichever occurs later. Thereafter inspect at intervals not to exceed 500 hours time in service or before the accumulation of 6,000 landings on the MLG axles, whichever occurs first. |\n\n|             | For aircraft fitted with MLG axles P/N 08-40021-2:Before accumulation of 6,000 landings on the MLG axles, and thereafter at intervals not to exceed 6,000 landings on the MLG axles.2.c. For aircraft fitted with MLG axles P/N 08-40021-3:Before accumulation of 50,000 landings on the MLG axles, and thereafter at intervals not to exceed 6,000 landings on the MLG axles. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n|             | This Airworthiness Directive becomes effective on 15 February 2007.                                                                                                                                                                                                                                                                                                            |\n| Background: | During a scheduled 500 hour inspection a crack was detected on the MLG axle of a Cresco aircraft. Inspection in accordance with PAC SL/CR/99-2 confirmed the crack. There is a known history of cracking of the MLG axle on Cresco aircraft.                                                                                                                                   |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n5 January 2007","sortOrder":0},{"sectionNumber":"AD/CRESCO/10","sectionType":"part","heading":"AD/CRESCO/10","content":"## AD/CRESCO/10","sortOrder":1},{"sectionNumber":"MLG Axles","sectionType":"part","heading":"MLG Axles","content":"## MLG Axles","sortOrder":2},{"sectionNumber":"2/2007","sectionType":"part","heading":"2/2007","content":"## 2/2007","sortOrder":3}],"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":6,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original scope as a targeted safety intervention for a specific known defect in a specific aircraft type. The inclusion of multiple part numbers and varying inspection methods reflects the evolution of the manufacturer's design solutions to the cracking problem, not mission creep. The directive remains tightly focused on MLG axle integrity for Cresco 08-600 aircraft."},"complexity_factors":["Multiple part number variants (3 different axle types) with distinct inspection requirements","Nested conditional compliance timelines based on both flight hours AND landing cycles (whichever occurs first)","Different inspection methods required for different part numbers (magnetic particle vs dye penetrant)","Multiple cross-references to external technical documents (Pacific Aerospace Corporation Maintenance Manual chapters 05, 12, 32; Service Letters PACSL/CR/06-1; Supplements PAC/CR/0442 and PAC/CR/0443; ASTM Standard E-1444)","Complex recurring inspection intervals with varying frequencies (150 hours/1,500 landings, 300 hours/3,000 landings, 500 hours/6,000 landings, 6,000 landings)","'Unless already accomplished' clauses creating exceptions to initial compliance deadlines","Five technical notes explaining part number substitutions and technical standards","Reference to New Zealand aviation authority directive (NZ CAA AD DCA/CRESCO/10) indicating trans-Tasman regulatory coordination"],"plain_english_summary":"Owners and operators of Pacific Aerospace Cresco 08-600 agricultural aircraft must inspect specific main landing gear axles (P/Ns 08-40021-1, -2, -3) for cracks using appropriate methods (magnetic particle or dye penetrant) and replace any cracked axles before flight. \n\nThis mandatory AD targets aircraft, maintenance engineers, and operators to prevent axle failure during landing after a crack was found—avoiding catastrophic loss of aircraft and life."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"This AD remains focused on the original safety objective: detecting and removing cracked MLG axles on Cresco 08-600 agricultural aircraft. It covers replacement axle part numbers introduced by PAC modifications and prescribes inspection methods and intervals for each. That broadening to include successor part numbers and associated fitment notes adjusts implementation detail but does not materially expand the AD's safety scope beyond addressing axle cracking."},"complexity_factors":["Three distinct axle part numbers (P/N 08-40021-1, -2, -3) with different inspection methods and intervals","Two different non-destructive test methods mandated (magnetic particle inspection equivalent to ASTM E-1444 and dye penetrant inspection)","Multiple timing metrics combined (hours in service and landing counts) with \"whichever occurs first/last\" conditions","Cross-references to several external documents: PAC Cresco 08-600 Maintenance Manual (multiple chapters/pages), PACSL/CR service instructions (Revision 1), and MOD documents (PAC/CR/0442 and PAC/CR/0443)","Notes adding fitment requirements for torque plates and historical context (replacement axles introduced by MODs)","Clear mandatory action (replace cracked axles before further flight) but technical execution delegated to multiple manual sections (adds procedural steps for maintainers)","Recurring inspection intervals that differ by inspection type and part number (nested intervals)"],"plain_english_summary":"**What this instrument does (mechanical changes)\n\n- Makes mandatory inspections and, where necessary, replacement of the main landing gear (MLG) axle on Pacific Aerospace Cresco 08-600 aircraft operating in the restricted-category agricultural role when that axle is one of these part numbers: P/N 08-40021-1, 08-40021-2 or 08-40021-3. (Applicability)\n\n- Requires disassembly of the MLG wheel assembly, cleaning of the axle, and inspection for security and cracks following the PAC Cresco 08-600 Maintenance Manual (MM) procedures and the PACSL service instructions referenced in the AD. (Requirement 1 & 2)\n\n- Specifies different non-destructive test methods depending on axle part-number:\n  - For P/N 08-40021-1 and 08-40021-2: magnetic particle inspection equivalent to ASTM E-1444 (a method for finding surface or just-below-surface cracks). (Requirement 1.c)\n  - For P/N 08-40021-3: dye penetrant inspection (a different crack detection method). (Requirement 2.c)\n\n- Requires that any axle found cracked be replaced before further flight, and that axles be reassembled and lubricated per the MM after inspection. (Requirement 1.c and 2.c)\n\n- Notes that certain torque plates (P/N 08-40055-2 and 08-40056-2) must be fitted when axles P/N 08-40021-2 or 08-40021-3 are installed. (Notes)\n\n- Establishes compliance timing: initial inspections within specified hours-in-service or landing-count windows after the effective date (15 February 2007), and recurring inspection intervals thereafter. Timing rules use the \"whichever occurs first/last\" style thresholds combining flight hours and landing counts. (Compliance)\n\n\nWhy the rule was issued (stated rationale)\n\n- The AD says a crack was detected during a scheduled 500-hour inspection and that there is a known history of MLG axle cracking on Cresco aircraft. The AD therefore requires inspections and replacement to ensure continued airworthiness. (Background)\n\n\nWho this affects and who pays\n\n- Affected parties: owners and operators of Cresco 08-600 aircraft operated in the restricted-category agricultural role fitted with MLG axles P/N 08-40021-1, -2 or -3. (Applicability)\n- Who pays: the aircraft owners/operators pay for the inspections, any required non-destructive testing, replacement axles and torque plates, labour and downtime. Maintenance organisations will carry out the work and may charge for NDT and parts fitting.\n\n\nPractical effects and behaviour changes required\n\n- Operators must schedule and perform the mandated disassembly and inspections, keep track of hours and landing counts to meet the AD thresholds, and remove and replace any cracked axles before flight. (Requirement & Compliance)\n- Where replacement axle types are installed (P/N 08-40021-2 or -3) operators must ensure the correct torque plates are fitted. (Notes)\n- Maintenance workshops will need capability or subcontract arrangements for magnetic particle inspection or dye penetrant inspection as specified. (Requirement 1.c / 2.c)\n\n\nCosts, incentives, trade-offs and implementation risks (analytical testing of the instrument's stated purpose)\n\n- Direct costs: inspection labour, NDT charges (magnetic particle or dye penetrant), parts (replacement axles and required torque plates), and aircraft downtime. These are borne by owners/operators (Requirement & Notes). The AD will increase short-term maintenance costs for affected operators.\n\n- Incentives: operators have an incentive to perform inspections on schedule to avoid being grounded if a crack is found. There is also an incentive to fit the later-design axles and torque plates if those reduce inspection frequency or long-term crack risk, but the AD applies inspections to those replacement parts as well (see different inspection methods and intervals for P/Ns).\n\n- Trade-offs: the rule increases pre-flight safety assurance at the cost of time and money. Frequent inspections reduce the chance of in-service failure but increase maintenance burden and downtime. The AD balances those by setting different intervals and inspection methods for different axle variants. (Requirement & Compliance)\n\n- Opportunity cost: time spent on inspections is time those aircraft cannot be used for agricultural work; smaller operators with tight schedules and margins will feel that opportunity cost more.\n\n- Implementation risk and compliance burden: the AD cross-references several specific chapters and pages of the PAC Cresco MM and PACSL service documents. This requires access to those documents and competent maintenance staff or approved NDT service providers. The differing inspection methods by P/N and the mixed hour/landing count thresholds increase procedural complexity for record-keeping and scheduling. (Requirement & Compliance)\n\n- Effects on private markets: demand for replacement axles, torque plates and specialised NDT services will increase, which benefits parts suppliers and maintenance providers. This concentrated demand could raise prices for these services temporarily. The AD does not itself change ownership rights or contractual freedom, but it imposes an operational constraint on owners/operators.\n\n- Enforcement and decision-making: CASA (through this AD) dictates the inspection and replacement requirements; maintenance organisations and operators decide how to schedule and procure the inspections and parts. The AD leaves technical execution to maintenance manuals and approved NDT processes cited in the Requirement.\n\n\nConcrete references in the instrument (where to look in the text)\n\n- Applicability: identifies Cresco 08-600 restricted-category agricultural aircraft with axle P/Ns 08-40021-1, -2, -3. (Applicability)\n- Requirement 1 and 2: step-by-step inspection and reassembly instructions, and the NDT methods required for each P/N. (Requirement 1 & 2)\n- Compliance: specific time-in-service and landing-count thresholds for initial and recurring inspections. (Compliance)\n- Notes: identifies replacement part history, torque plate fitment and the ASTM standard referenced for magnetic particle inspection. (Notes)\n\n\nBottom line\n\n- Mechanically: this AD forces regular disassembly, visual and NDT inspection, and replacement if cracked, for specific Cresco MLG axles, with part-number-specific inspection methods and schedules. (Requirement & Compliance)\n- Purpose: the stated purpose is to detect and remove cracked axles to maintain airworthiness after a crack was found and given the known history of axle cracking. (Background)\n- Cost and burdens fall on operators and maintenance providers; the AD increases demand for parts and NDT services and requires careful record-keeping to meet the mixed hours/landing-count thresholds. (Requirement, Notes & Compliance)\n"}},"importantCases":[],"_links":{"self":"/api/acts/ad-cresco-10-mlg-axles","history":"/api/acts/ad-cresco-10-mlg-axles/history","analysis":"/api/acts/ad-cresco-10-mlg-axles/analysis","conflicts":"/api/acts/ad-cresco-10-mlg-axles/conflicts","importantCases":"/api/acts/ad-cresco-10-mlg-axles/important-cases","documents":"/api/acts/ad-cresco-10-mlg-axles/documents"}}