{"id":"F2006B02296","name":"AD/AL 60/11 - Engine Mounting Plates - Inspection and Modification","slug":"ad-al-60-11-engine-mounting-plates-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41526,"registerId":"commonwealth-F2006B02296-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AL 60/11 - Engine Mounting Plates - Inspection and Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Aermacchi - Lockheed AL 60 Series Aeroplanes\n\n \n\n# AD/AL 60/11 Engine Mounting Plates - Inspection\n\nand Modification\n\nApplicability: All models not incorporating Modification MB-L-001.\n\n# 2/75\n\n \n\nRequirement: 1. Inspect the engine mounting plates for cracks using a Dye Penetrant Technique in accordance with Aermacchi Lockheed Service Bulletin No. SB-L-0003.\n\n \n\n2. Modify the engine mounting plates in accordance with Aermacchi Lockheed Modification Bulletin No. MB-L-0001.\n\n \n\nCompliance: For para. 1 - Within 10 hours’ time in service after 20 January 1975 and thereafter at intervals not exceeding 100 hours’ time in service until modified.\n\n \n\nFor para. 2 - Before achieving 1200 hours total time in service.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive, as presented, applies to all AL 60 series aircraft not incorporating Modification MB‑L‑001 and prescribes inspection until the modification is completed and a deadline for that modification (Applicability; Requirement; Compliance). The text does not show an expansion or narrowing of that applicability or obligations relative to its expressed content here, so there is no indication in the supplied text that the scope has changed from the instrument’s stated terms."},"complexity_factors":["Two discrete mandatory actions (inspection for cracks; modification) rather than multiple conditional pathways","Clear, short compliance timelines (first inspection within 10 hours after the date; 100‑hour inspection intervals; modification before 1,200 total hours)","Dependence on external technical documents (Service Bulletin SB‑L‑0003 and Modification Bulletin MB‑L‑0001) for procedure and technical details","A specified inspection technique (Dye Penetrant) requiring appropriate materials/skills","Limited applicability clause (all models not incorporating MB‑L‑001) which is simple to determine"],"plain_english_summary":"- What this instrument requires, mechanically:\n  - It requires a specific inspection and then a one‑off modification of the engine mounting plates on Aermacchi–Lockheed AL 60 series aeroplanes that do not already have Modification MB‑L‑001 installed (Applicability; Requirement).  \n  - The inspection must look for cracks using a dye‑penetrant technique and must be carried out in the manner set out in Aermacchi Lockheed Service Bulletin SB‑L‑0003 (Requirement para. 1).  \n  - The modification must be carried out in accordance with Aermacchi Lockheed Modification Bulletin MB‑L‑0001 (Requirement para. 2).\n\n- When the work must be done (timing and intervals):\n  - The first inspection is required within 10 hours’ time in service after 20 January 1975, and thereafter at intervals not exceeding 100 hours’ time in service until the modification is completed (Compliance for para. 1).  \n  - The modification must be completed before the aeroplane reaches 1,200 hours total time in service (Compliance for para. 2).\n\n- Who is affected and who decides: \n  - All AL 60 aircraft that do not incorporate MB‑L‑001 are subject to these actions (Applicability).  \n  - The Civil Aviation Safety Authority issues the directive under the Civil Aviation Regulations framework (title/header).  \n  - Aircraft operators/owners (and their nominated maintenance organisations) are the parties who must arrange and carry out the inspections and the modification to meet the stated compliance times (Applicability; Requirement; Compliance).\n\n- Why it matters (as stated and as implied by the mechanics):\n  - The directive explicitly directs inspections for cracks in the engine mounting plates (Requirement para. 1) and then prescribes a modification (Requirement para. 2). The mechanical effect is to create an interim, recurring inspection obligation until a specified modification is installed, and a mandatory deadline by which the modification must be completed (Compliance).\n\n- Practical consequences, incentives and trade‑offs (source‑grounded):\n  - Recurring inspection cost vs one‑off modification: while the modification remains uninstalled, operators must undertake inspections every 100 hours (Compliance for para. 1). That creates an ongoing maintenance burden (time in service lost to inspection, labour and consumables) until the modification is completed, after which the recurring inspections stop (the inspection interval requirement explicitly continues \"until modified\") (Compliance for para. 1).  \n  - Scheduling and operational impact: the first inspection deadline is immediate relative to the effective date (within 10 hours after 20 January 1975) and the modification has a hard deadline (before 1,200 hours total time) (Compliance). Operators must schedule work to meet those windows.  \n  - Technical dependency and compliance burden: the inspection and modification must follow the manufacturer’s published service and modification bulletins (SB‑L‑0003 and MB‑L‑0001) (Requirement). Compliance therefore requires access to those documents and the capability to carry out dye‑penetrant inspections and the specified modification; operators who lack that capability will need to arrange competent maintenance providers.  \n  - Who pays: the instrument places the obligation on operators/owners to have the inspections and modification carried out (Applicability; Requirement; Compliance). The direct costs (labour, parts, downtime) fall to those operators/owners.  \n\n- Implementation risks and limits (as reflected in the text):\n  - The directive prescribes the diagnostic method (dye‑penetrant) and points maintenance to the manufacturer’s bulletins (Requirement), so detection and corrective work are dependent on following those procedures accurately.  \n  - The text sets firm time limits for inspection and for modification (Compliance). Meeting those limits requires operators to plan maintenance; failure to comply would leave the aircraft outside the AD’s requirements.\n\n- Summary statement of effect:\n  - The AD imposes a short‑interval inspection regime for cracking of engine mounting plates on affected AL 60 aeroplanes, and mandates a manufacturer‑specified modification to be completed by a fixed total‑time deadline. The direct burdens are recurring inspections until the modification is done and the one‑off modification work itself; the AD relies on manufacturer bulletins for the technical method and modification details (Requirement; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of ensuring engine mounting plate integrity in the AL 60 series."},"complexity_factors":["Very short document (under 200 words)","Only 2 substantive requirements (inspection and modification)","Single defined term: 'Modification MB-L-001' referenced by applicability","Clear, unambiguous compliance deadlines with simple time-in-service calculations","No nested exceptions or conditional logic","Direct reference to external technical documents (Service Bulletin and Modification Bulletin) rather than incorporating their text","Single applicability criterion (all models not incorporating one specific modification)"],"plain_english_summary":"This is an **Airworthiness Directive** (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nThis directive requires owners and operators of **Aermacchi-Lockheed AL 60 series aeroplanes** to inspect and modify the engine mounting plates (the metal brackets that hold the engine to the aircraft frame).\n\n**Who it affects:**\n- Owners and operators of all Aermacchi-Lockheed AL 60 models that **haven't already been modified** with a specific factory update called \"Modification MB-L-001\"\n- Maintenance engineers who perform the work\n\n**What must be done:**\n1. **Inspection:** Check the engine mounting plates for cracks using a \"dye penetrant\" technique (a special chemical test that makes tiny cracks visible) — following the manufacturer's Service Bulletin SB-L-0003\n2. **Modification:** Reinforce or replace the mounting plates following the manufacturer's Modification Bulletin MB-L-0001\n\n**When it must be done:**\n- **Inspections:** First one within 10 flight hours after 20 January 1975, then repeated every 100 flight hours until the modification is done\n- **Modification:** Must be completed before the aircraft reaches 1,200 total flight hours\n\n**Why it matters:**\nEngine mounting plates carry enormous stress. Cracks in these plates could cause the engine to detach in flight — catastrophic failure. This AD prevents that by catching problems early and mandating a permanent fix."}},"importantCases":[],"_links":{"self":"/api/acts/ad-al-60-11-engine-mounting-plates-inspection-and-modification","history":"/api/acts/ad-al-60-11-engine-mounting-plates-inspection-and-modification/history","analysis":"/api/acts/ad-al-60-11-engine-mounting-plates-inspection-and-modification/analysis","conflicts":"/api/acts/ad-al-60-11-engine-mounting-plates-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-al-60-11-engine-mounting-plates-inspection-and-modification/important-cases","documents":"/api/acts/ad-al-60-11-engine-mounting-plates-inspection-and-modification/documents"}}