{"id":"F2007L00112","name":"AD/CRESCO/9 - MLG Lower Torque Links","slug":"ad-cresco-9-mlg-lower-torque-links","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68195,"registerId":"commonwealth-F2007L00112-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/9 | MLG Lower Torque Links | 2/2007 |\n| ----------- | ---------------------- | ------ |\n\n| Applicability: | Model 08-600 aircraft on restricted category agricultural operations, fitted with main landing gear (MLG) lower pivot torque link bolts part number (P/N) NAS 1307-78D.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Inspect the MLG torque link assemblies for wear in accordance with the maintenance schedule in Chapter 05-10-00 page 615, and the MLG wear limits in Chapter 32-10-00 page 601, of Pacific Aerospace Corporation (PAC) Cresco08-600 Maintenance Manual.Replace or rework worn parts as required, before further flight.Replace a worn lower torque link assembly P/N 08-40091-1, or incorporate MOD PAC/CR/0435, before further flight.2. Remove the MLG lower pivot torque link bolt in accordance with Chapter 32 of the PAC Cresco 08-600 Maintenance Manual.a. Inspect the lower pivot torque link bolts using an approved direct or indirect magnetic particle inspection method that is equivalent to ASTM International Standard No. E-1444.Replace cracked bolts before further flight.b. Re-assemble and lubricate the lower torque link assembly in accordance with Chapters 32 and 12 of PAC Cresco 08-600 Maintenance Manual. Torque the MLG lower pivot torque link bolts 180 to 210 inch-pounds.Note 1: 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 2: MOD PAC/CR/0300 is the installation of alternate lower torque link bolts and torque plate assemblies.Note 3: MOD PAC/CR/0435 introduces replaceable bushes in accordance with PAC Drawing 08-03179. Lower torque link assemblies P/N 08-40091-1 can be reworked and re-identified as P/N 08-40031-4 if the wear damage does not exceed the rework dimensions in PAC Drawing 08-03179.Note 4: NZ CAA AD DCA/CRESCO/9 refers. |\n\n| Compliance: | Within 150 hours time in service after 15 February 2007 or before MLG lower pivot torque link bolts exceed 300 hours time in service, whichever occurs later. Inspect thereafter at intervals not to exceed 300 hours time in service.                                                                                                  |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Airworthiness Directive becomes effective on 15 February 2007.                                                                                                                                                                                                                                                                     |\n| Background: | The NZ CAA received a substantial number of reports of Cresco 08-600 MLG lower torque link bolts with cracks under the bolt head. The currently installed bolt does not appear to be adequate for all working applications. This Directive requires inspection of the MLG torque link assemblies and MLG lower pivot torque link bolts. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n5 January 2007","sortOrder":0},{"sectionNumber":"AD/CRESCO/9","sectionType":"part","heading":"AD/CRESCO/9","content":"## AD/CRESCO/9","sortOrder":1},{"sectionNumber":"MLG Lower Torque Links","sectionType":"part","heading":"MLG Lower Torque Links","content":"## MLG Lower Torque Links","sortOrder":2},{"sectionNumber":"2/2007","sectionType":"part","heading":"2/2007","content":"## 2/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"This directive is narrowly focused on addressing reported cracking of the specified MLG lower pivot torque link bolts on PAC Cresco 08‑600 agricultural aircraft. It imposes inspection, repair/replacement and torque requirements tied to existing maintenance manuals and identified MODs. The measures are consistent with the stated original purpose (remediating cracked bolts/wear) and do not add unrelated regulatory obligations or broaden applicability beyond the aircraft model, operation type and part number identified in the directive."},"complexity_factors":["Narrow applicability combining aircraft model, operation type (restricted‑category agricultural), and specific bolt part number (NAS 1307‑78D)","Cross‑references to multiple external documents: PAC Cresco 08‑600 Maintenance Manual (specific chapters and page numbers), PAC drawing 08‑03179, and MODs PAC/CR/0435 and PAC/CR/0300","Use of a technical non‑domestic inspection standard (ASTM E‑1444) as an acceptance criterion for MPI","Conditional compliance timing: initial action within 150 hours after a fixed date OR before bolts exceed 300 hours, whichever occurs later, plus recurring 300‑hour intervals","Options and branching: replace assembly, rework and re‑identify part number, or incorporate an approved MOD — each option requires different work and documentation","Specific reassembly torque range requirement (180–210 inch‑pounds) creating a precision compliance element","Notes that create implementation detail (reidentification of reworked parts, alternate MODs), increasing recordkeeping complexity","Requirement to use either direct or indirect MPI methods (technical choice affects who can perform the work)"],"plain_english_summary":"**What this directive does (mechanical changes first)**\n\n- Requires operators of Pacific Aerospace Cresco 08‑600 aeroplanes (used on restricted‑category agricultural operations) that have the lower pivot torque link bolts P/N NAS 1307‑78D to inspect, repair or replace parts of the main landing gear (MLG) lower torque link assemblies and to inspect the lower pivot torque link bolts using magnetic particle inspection (MPI).\n- If a lower torque link assembly P/N 08‑40091‑1 is worn it must be replaced or modified (MOD PAC/CR/0435) before the aircraft flies again. Cracked lower pivot torque link bolts must be replaced before further flight.\n- After any work, the lower torque link assembly must be reassembled, lubricated and the lower pivot torque link bolts torqued to 180–210 inch‑pounds.\n\n**Who this affects**\n\n- Owners and operators of PAC Cresco 08‑600 aircraft operated on restricted‑category agricultural work that currently use the specified bolt part number (P/N NAS 1307‑78D).\n- Maintenance organisations and mechanics who perform inspections and repairs for those aircraft, and facilities that perform magnetic particle inspections.\n\n**Why it matters (stated problem and mechanical risk)**\n\n- The NZ Civil Aviation Authority received multiple reports of cracks beneath the head of the specified lower pivot torque link bolt. Cracked or excessively worn torque link parts can impair the main landing gear operation and therefore present an airworthiness and safety risk.\n\n**How it works in practice**\n\n- Applicability: only Model 08‑600 Cresco aircraft on restricted‑category agricultural operations fitted with the specified bolt (P/N NAS 1307‑78D).\n- Inspections and repairs must follow the PAC Cresco 08‑600 Maintenance Manual (specific chapters called out for wear limits and procedures).\n- Bolt inspection must use an approved direct or indirect magnetic particle inspection method that meets ASTM E‑1444; any cracked bolt found must be removed and replaced before further flight.\n- Rework of lower torque link assemblies is allowed if the wear is within the rework dimensions on PAC drawing 08‑03179; reworked parts are re‑identified as P/N 08‑40031‑4. Alternatively, operators may install the MOD that introduces replaceable bushes (MOD PAC/CR/0435) or install an alternate bolt/torque plate assembly (MOD PAC/CR/0300).\n- Torque specification on reassembly: 180–210 inch‑pounds.\n\n**Timing and recurring requirements**\n\n- Initial compliance: within 150 hours time‑in‑service after 15 February 2007, or before the bolts exceed 300 hours time‑in‑service, whichever occurs later.\n- Re‑inspection interval after the initial check: not to exceed 300 hours time‑in‑service between inspections.\n\n**Who pays, who decides, and what changes in behaviour**\n\n- Operators (aircraft owners/operators) pay for inspections, MPI tests, parts replacement or rework, any MOD installations, and associated labour and downtime.\n- The Civil Aviation Safety Authority (via its delegate) issued the directive; maintenance organisations decide how to comply so long as the specified manual procedures and inspection standards are met.\n- Behaviour changes: operators must schedule recurring inspections, use MPI for bolt checks, replace or rework worn/ cracked components, and maintain a tighter torque control on assembly.\n\n**Costs, incentives and implementation issues to consider**\n\n- Direct costs: MPI testing (may require specialist equipment or outsourced laboratory), replacement bolts or assemblies, rework/mod installation, and aircraft downtime (opportunity cost for agricultural operators during peak seasons).\n- Supply risk: availability of replacement parts or MOD kits could delay compliance and extend downtime.\n- Compliance burden: the AD cross‑references the PAC maintenance manual and two MODs; maintenance staff must follow specific chapters and drawings, and meet an ASTM inspection standard (ASTM E‑1444).\n- Small operators are more exposed to per‑aircraft fixed compliance costs (concentrated cost on a small group of operators). The AD does not provide allowances or alternatives other than the specified MODs and rework limits.\n\n**Trade‑offs and risk management**\n\n- The directive substitutes increased maintenance (inspection and possible replacement/modification) for the risk of in‑service bolt cracking. The trade‑off is the immediate cost, downtime and logistics of inspections versus the safety risk of undetected bolt cracks that could lead to MLG failure.\n\n(References: applicability, requirement and compliance timing as set out in the directive.)"},"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 is a targeted safety directive addressing a specific mechanical failure mode (cracking MLG bolts) in a specific aircraft type. The scope remains precisely limited to the identified safety risk and has not expanded beyond the original intent of preventing landing gear failures."},"complexity_factors":["Highly specific technical scope — applies only to one aircraft model (Cresco 08-600) with specific part numbers (NAS 1307-78D bolts)","Multiple cross-references to external technical documents: PAC Cresco 08-600 Maintenance Manual Chapters 05-10-00, 32-10-00, 32, and 12; PAC Drawing 08-03179; ASTM Standard E-1444; and modification references MOD PAC/CR/0435 and MOD PAC/CR/0300","Conditional compliance timing: 'whichever occurs later' creates a dual-threshold test for the initial inspection","Technical jargon throughout (e.g., 'magnetic particle inspection', 'ferromagnetic material', 'inch-pounds torque', 'rework dimensions')","Nested requirements: inspection → potential replacement OR modification → re-assembly with specific torque values → ongoing periodic inspections","Short document (approximately 400 words) with straightforward structure: Applicability, Requirement, Compliance, Background"],"plain_english_summary":"Owners/operators of Pacific Aerospace Cresco 08-600 agricultural aircraft must inspect and, if necessary, magnetic-particle test and replace lower torque link bolts (PN NAS1307-78D) and worn torque link assemblies after reports of bolt cracking. Cracked bolts can cause landing gear collapse, risking loss of aircraft and pilot during low-level agricultural work.\n\nInspections start within the specified flight-hour window and repeat periodically; aircraft with cracked bolts are grounded until repaired. This AD aligns with New Zealand’s directive and references an approved durable modification."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cresco-9-mlg-lower-torque-links","history":"/api/acts/ad-cresco-9-mlg-lower-torque-links/history","analysis":"/api/acts/ad-cresco-9-mlg-lower-torque-links/analysis","conflicts":"/api/acts/ad-cresco-9-mlg-lower-torque-links/conflicts","importantCases":"/api/acts/ad-cresco-9-mlg-lower-torque-links/important-cases","documents":"/api/acts/ad-cresco-9-mlg-lower-torque-links/documents"}}