{"id":"F2006B07624","name":"AD/Z 526/1 - Elevator Control Countershaft Lever","slug":"ad-z-526-1-elevator-control-countershaft-lever","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":50351,"registerId":"commonwealth-F2006B07624-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/Z 526/1 - Elevator Control Countershaft Lever","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nMorovan Zlin Z 526 Series Aeroplanes\n\nAD/Z 526/1 Elevator Control Countershaft Lever 3/95\n\nApplicability: All Z 526 F, Z 526 L and Z 526 AFS models.\n\nRequirement: 1. Visually inspect the elevator control countershaft lever for cracking with a 10x glass. Inspect in accordance with Moravan Service Bulletin (SB) Z 526/58 Process of Work, Part 1.\n\n2. Replace the elevator control countershaft P/N Z 326.314.1 with new P/N Z\n\n326.314.2 in accordance with Moravan SB Z 526/58 Process of Work, Part 2.\n\nCompliance: 1. Initially inspect before 10 hours time in service after 2 March 1995 or before 2 April 1995, whichever occurs first. Re-inspect at intervals not to exceed 100 hours time in service.\n\n2. Replace the countershaft before 2 September 1995.\n\nNote: Countershaft replacement does not cancel the Requirement 1 inspection.\n\nBackground: There is a potential for fatigue cracking in the elevator control countershaft.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The supplied text sets out new or specific obligations (inspection intervals and a mandated part-number replacement) for the listed Z 526 models. The instrument itself does not include any information indicating a change in scope from an earlier instrument or from its original intent; it simply establishes the inspection and replacement obligations and their timing (Applicability; Requirement 1–2; Compliance 1–2; Note; Background)."},"complexity_factors":["Applicability limited to three specific aircraft models (straightforward scope).","Two distinct mandatory actions: recurring visual inspections and a one‑time part replacement (adds procedural steps).","Precise procedural references to an external Service Bulletin (SB Z 526/58 Parts 1 and 2) requiring reliance on another document for implementation details.","Fixed, short compliance windows and recurring inspection intervals that require scheduling and record-keeping (Compliance 1–2).","Explicit retention of inspection obligation after replacement (Note) which increases ongoing compliance monitoring."],"plain_english_summary":"What this instrument does\n\n- Requires owners/operators of Morovan Zlin Z 526 series aeroplanes (models Z 526 F, Z 526 L and Z 526 AFS) to carry out a specified inspection and to replace a specified elevator control countershaft part (Applicability; Requirement 1–2).\n\nHow it works mechanically\n\n- Inspect: A visual inspection for cracking of the elevator control countershaft lever using a 10x magnifying glass, carried out in accordance with Morovan Service Bulletin (SB) Z 526/58 Process of Work, Part 1 (Requirement 1).\n- Replace: Replace the existing countershaft part number P/N Z 326.314.1 with the new part P/N Z 326.314.2 in accordance with Morovan SB Z 526/58 Process of Work, Part 2 (Requirement 2).\n- Timing: The first inspection must be done within 10 hours time in service after 2 March 1995 or before 2 April 1995, whichever is earlier, and then at intervals not exceeding 100 hours time in service (Compliance 1). The replacement must be completed before 2 September 1995 (Compliance 2).\n- Continued inspection: Replacing the countershaft does not remove the need to keep performing the inspections described in Requirement 1 (Note).\n\nWho this affects and who pays\n\n- Affected parties: Owners and operators of the listed Z 526 models (Applicability).\n- Who pays: The owners/operators bear the direct costs of performing the inspections, obtaining and fitting the replacement part, and any associated aircraft downtime (Requirement 1–2; Compliance 1–2).\n- Who decides/complies: The operator (or their maintenance organisation) must carry out the inspections and arrange the part replacement to meet the specified dates and intervals (Requirement 1–2; Compliance 1–2).\n\nWhy it was issued (official rationale) and how that interacts with costs and incentives\n\n- Stated reason: The background states there is a potential for fatigue cracking in the elevator control countershaft (Background). That is the declared safety concern that the inspection and replacement intend to address.\n- Incentives and trade-offs: The directive creates a clear incentive for prompt replacement and ongoing inspections to reduce the risk associated with fatigue cracking. The trade-off for operators is the upfront and ongoing costs of inspections and replacement and the aircraft downtime required to accomplish them (Requirement 1–2; Compliance 1–2). The service bulletin references (SB Z 526/58 Parts 1 and 2) set the technical method; the effectiveness of the measure therefore depends on faithful implementation of those procedures (Requirement 1–2).\n\nCompliance burden, discretion and implementation risk\n\n- Compliance burden: Recurring inspections at 100‑hour intervals and a mandatory replacement deadline impose a predictable, recurrent maintenance task and a one‑time parts procurement and installation cost (Compliance 1–2; Note).\n- Discretion: The instrument specifies the inspection method (10x glass) and references specific service bulletin parts for procedure, leaving limited operational discretion about how and when to comply beyond meeting the stated intervals and dates (Requirement 1; Requirement 2; Compliance 1–2).\n- Implementation risk: The inspection relies on visual detection with a 10x glass and on adherence to the Morovan service bulletin procedures; therefore detection sensitivity and workmanship quality are central to the directive’s practical effectiveness (Requirement 1; Requirement 2).\n\nEffects on suppliers and market interactions\n\n- Parts and maintenance market: Operators need to obtain P/N Z 326.314.2 and use appropriate maintenance capacity to fit it. This concentrates immediate demand on suppliers of that part and on maintenance providers capable of performing the SB procedures (Requirement 2).\n- Private-choice effects: The directive constrains operators’ maintenance and procurement choices for the specified component until the replacement is fitted and ongoing inspections are satisfied (Requirement 1–2; Compliance 1–2).\n\nNet procedural note\n\n- The instrument imposes a two‑step compliance path (inspect regularly; replace by a deadline) and explicitly keeps the inspection requirement in force even after replacement, so operators must budget both recurring inspection effort and the one‑off replacement (Requirement 1–2; Compliance 1–2; Note)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original, narrow scope. It addresses a specific safety defect in a specific part on specific aircraft models. There is no evidence of scope creep; the directive remains tightly focused on the elevator control countershaft lever issue as originally identified."},"complexity_factors":["Single, specific technical subject matter (one aircraft part on three specific models)","Only 2 main requirements with clear, unambiguous deadlines","Minimal defined terms (only standard aviation abbreviations like 'P/N' for part number and 'SB' for Service Bulletin)","No nested conditional logic or cross-referencing to other legislation","Straightforward compliance structure with specific dates and flight hours","Single background sentence explaining the safety rationale"],"plain_english_summary":"This is a **safety notice for aircraft owners and operators** of specific Morovan Zlin Z 526 model aeroplanes (the Z 526 F, Z 526 L, and Z 526 AFS).\n\n**What it does:**\nThe Civil Aviation Safety Authority (CASA) has identified a safety risk with these planes. The **elevator control countershaft lever** — a critical part that helps control the plane's up-and-down movement (pitch) — can develop **fatigue cracks** over time. If this part fails in flight, the pilot could lose control of the aircraft's pitch.\n\n**What owners must do:**\n\n1. **Inspect the part:** Using a 10x magnifying glass (a \"10x glass\"), visually check the elevator control countershaft lever for cracks. This must be done following the manufacturer's specific instructions (Moravan Service Bulletin Z 526/58, Part 1).\n   - **First inspection:** Must happen before the plane reaches 10 hours of flying time after 2 March 1995, or before 2 April 1995 — whichever comes first.\n   - **Ongoing inspections:** Must be repeated every 100 hours of flying time.\n\n2. **Replace the part:** Swap out the old countershaft (part number Z 326.314.1) with a new, improved version (part number Z 326.314.2), following the manufacturer's instructions (Moravan Service Bulletin Z 526/58, Part 2).\n   - **Deadline:** Must be done before 2 September 1995.\n\n**Important note:** Even after you replace the part, you still have to keep doing the inspections.\n\n**Why it matters:**\nFatigue cracking is when metal weakens and cracks after repeated stress (like the way a paperclip breaks if you bend it back and forth). This directive prevents potential catastrophic failure of the aircraft's pitch control system, which could lead to loss of control and crash."}},"importantCases":[],"_links":{"self":"/api/acts/ad-z-526-1-elevator-control-countershaft-lever","history":"/api/acts/ad-z-526-1-elevator-control-countershaft-lever/history","analysis":"/api/acts/ad-z-526-1-elevator-control-countershaft-lever/analysis","conflicts":"/api/acts/ad-z-526-1-elevator-control-countershaft-lever/conflicts","importantCases":"/api/acts/ad-z-526-1-elevator-control-countershaft-lever/important-cases","documents":"/api/acts/ad-z-526-1-elevator-control-countershaft-lever/documents"}}