{"id":"F2006B08142","name":"AD/CESSNA 310/15 Amdt 1 - Nose Gear Main Drive Tube Assembly","slug":"ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115293,"registerId":"commonwealth-F2006B08142-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 310/15 Amdt 1 - Nose Gear Main Drive Tube Assembly","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)  \nCessna 310 Series Aeroplanes\n\nAD/CESSNA310/15\n\nAmdt 1\n\n  \nNose Gear Main Drive Tube Assembly 9/91\n\nApplicability: All models which have exceeded 1000 hours time in service; and with bearing P/N 4NBC612ZP fitted to nose gear drive tube P/N 0842120-1.\n\nRequirement: Inspect the affected bearing for movement between the outer bearing race and the eye end of the nose gear main drive tube.\n\nCompliance: At intervals not to exceed 200 hours time in service. The compliance date of the original issue of this Directive was 5 September 1968. This reissue is effective from 5 September 1991.\n\nBackground: The initial issue of this Directive was raised in response to three incidents; one of which resulted in an accident. This amendment is raised to clarify applicability.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The amendment states it was raised to clarify applicability (Background). The reissue restates the original inspection requirement (inspect the specified bearing for movement) and the 200‑hour inspection interval (Requirement; Compliance). The text does not introduce new inspection actions, intervals, or expanded applicability criteria beyond clarification, so the operational scope of the directive is not changed by this amendment."},"complexity_factors":["Narrow technical scope: applies only to Cessna 310 models with >1,000 hours TIS and with bearing P/N 4NBC612ZP fitted to drive tube P/N 0842120-1 (Applicability).","Single, straightforward required action: inspect for movement between the outer bearing race and the eye end of the nose gear main drive tube (Requirement).","Simple, fixed compliance interval: inspections at intervals not to exceed 200 hours TIS (Compliance).","Potential ambiguity in inspection criterion: \"movement\" is not quantitatively defined, leaving room for variation in inspection technique and recordkeeping (Requirement).","Administrative tracking: operators must track both airframe hours and part-fitment to determine applicability, which adds minor record-keeping complexity (Applicability)."],"plain_english_summary":"What this instrument does\n\n- Requires operators of Cessna 310 series aeroplanes that have more than 1,000 hours time in service and that have bearing P/N 4NBC612ZP fitted to the nose gear drive tube P/N 0842120-1 to inspect that bearing for movement between the outer bearing race and the eye end of the nose gear main drive tube (Requirement; Applicability).\n- Sets the inspection interval at no more than every 200 hours time in service (Compliance). The directive was reissued effective 5 September 1991; the original compliance date was 5 September 1968 (Compliance).\n\nWho this affects\n\n- Owners and operators of Cessna 310 series aeroplanes meeting the applicability criteria (Applicability).\n- The personnel or maintenance organisations who carry out the inspections and any follow-up maintenance.\n\nWhy it matters (stated purpose and practical implications)\n\n- The stated rationale is that the original directive followed three incidents, one of which resulted in an accident; this amendment clarifies which aircraft/parts are covered (Background). The inspection requirement mechanically aims to detect movement of a specified bearing relative to the nose gear drive tube.\n\nCosts, incentives and trade-offs (mechanical effects)\n\n- Who pays: Operators/owners (and their maintenance providers) bear the direct cost of performing recurring inspections and any consequential maintenance because the directive requires inspections at specified intervals (Applicability; Requirement; Compliance).\n- Incentives created: Recurrent inspections create an ongoing maintenance expense but provide a mechanism to detect a particular failure mode (bearing movement) before it leads to an incident (Requirement; Background).\n- Trade-offs and opportunity costs: Operators must allocate maintenance labour and aircraft downtime to meet the 200‑hour inspection interval; that is time and money not available for other uses (Compliance).\n- Implementation risk and compliance burden: The directive specifies the item to inspect and the inspection interval but does not prescribe a detailed measurement method. That leaves some practical discretion to maintenance personnel about how to detect and record \"movement\", which can affect consistency and enforcement (Requirement).\n\nEffects on private choice, business and markets\n\n- The requirement is narrowly targeted by model, time-in-service and part numbers (Applicability). It does not direct who must perform the inspection beyond the normal regulatory expectation that operators/maintenance organisations comply, nor does it mandate part replacements in the text provided (Requirement; Compliance).\n- Impact on competition and business: The AD imposes a recurring operational cost on affected aircraft. That cost is borne by individual operators and may influence decisions about aircraft deployment, maintenance scheduling, or part selection where alternative parts or configurations exist (Applicability; Requirement). The text does not specify approved alternatives or exemptions.\n\nConcrete mechanics to note\n\n- Applicability requires both a service-hours threshold (>1000 hours TIS) and the presence of a specific bearing and drive-tube part number to trigger the inspection requirement (Applicability).\n- The inspection cycle is fixed at intervals not to exceed 200 hours TIS (Compliance).\n- The amendment's stated purpose is to clarify applicability rather than to change the inspection action or interval (Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment does not expand scope. It is a technical clarification amendment ('Amdt 1') that narrows and clarifies applicability criteria without altering the underlying safety mandate or introducing new requirements. The original 1968 directive addressed the same safety risk; this 1991 reissue simply makes clearer which specific aircraft configurations are affected."},"complexity_factors":["Extremely short document (under 200 words)","Only 2 defined part numbers (P/N 4NBC612ZP and P/N 0842120-1)","Single, clear mechanical inspection requirement","Simple binary applicability test (1000+ hours AND specific parts fitted)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","No nested conditions or exceptions","Straightforward compliance interval (200 hours time in service)"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a recall notice for aircraft, but legally binding.\n\n**What it does:** It requires owners and operators of certain **Cessna 310 series aeroplanes** to inspect a specific part of the nose landing gear (the \"main drive tube assembly\") for a dangerous mechanical fault.\n\n**Who it affects:** \n- **Aircraft:** All Cessna 310 models that have flown more than 1,000 hours AND have a specific bearing part number (P/N 4NBC612ZP) installed in a specific drive tube (P/N 0842120-1).\n- **People:** Aircraft owners, maintenance engineers, and operators responsible for keeping these planes airworthy.\n\n**What must be done:** Inspect the bearing for unwanted movement between the outer race (the ring that holds the ball bearings) and the \"eye end\" (the loop-shaped fitting) of the drive tube. This check must happen **every 200 flight hours**.\n\n**Why it matters:** The original directive was issued after three incidents — one causing a crash — where this bearing failed. This 1991 amendment simply clarifies which specific aircraft are affected, without changing the safety requirement itself. Ignoring this directive makes an aircraft unairworthy and illegal to fly."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly","history":"/api/acts/ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly/history","analysis":"/api/acts/ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly/analysis","conflicts":"/api/acts/ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly/conflicts","importantCases":"/api/acts/ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly/important-cases","documents":"/api/acts/ad-cessna-310-15-amdt-1-nose-gear-main-drive-tube-assembly/documents"}}