{"id":"F2006B04930","name":"AD/CESSNA 150/32 Amdt 1 - Horizontal Stabiliser Forward Attachment","slug":"ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44775,"registerId":"commonwealth-F2006B04930-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 150/32 Amdt 1 - Horizontal Stabiliser Forward Attachment","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 150, F150, 152 & F152 Series Aeroplanes\n\nAD/CESSNA 150/32\n\nAmdt 1\n\n  \nHorizontal Stabiliser Forward Attachment 12/85\n\nApplicability: All models A150, A152, FA150, FA152, FRA150 and FRA152. Requirement: To detect cracking in the horizontal stabiliser forward attachment nutplate:\n\n    Gain access to horizontal stabiliser forward attachment area.\n\n    2. Visually inspect nutplates for cracking and/or structural distress.\n\n    3. Visually inspect the horizontal stabiliser structure in the attachment area for cracking and/or structural distress.\n\nCompliance: Within 100 hours time in service after 31 December 1985, or at the next scheduled inspection for Maintenance Release issue after 31 December 1985, whichever is the later and thereafter at each issue of a new Maintenance Release.\n\nBackground: This amendment extends the repeat inspection frequency to coincide with the periodic inspection.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment changes the repeat inspection frequency so that repeat inspections coincide with the aircraft’s periodic Maintenance Release inspections. The Background explicitly states the amendment extends the repeat inspection frequency to align with periodic inspections, which modifies how often and when the required visual checks are scheduled relative to the previous AD requirements. (Background; Compliance)"},"complexity_factors":["Narrow applicability to a specific set of aircraft models (A150, A152, FA150, FA152, FRA150, FRA152). (Applicability)","Prescriptive, but simple, three-step visual inspection procedure (gain access; inspect nutplates; inspect stabiliser structure). (Requirement)","Compliance timing tied to Maintenance Release issuance rather than a fixed calendar interval, requiring administrative coordination with maintenance scheduling. (Compliance; Background)","Potential need to gain access or partially disassemble the attachment area increases practical inspection difficulty and labour time. (Requirement)","The AD mandates detection action but does not specify corrective repairs or remediation procedures if cracking is found, leaving follow-up actions to maintenance judgement. (Requirement)","Change in repeat inspection frequency to coincide with periodic inspections alters prior inspection cadence and may require operators to adjust maintenance planning. (Background)"],"plain_english_summary":"What this instrument does\n\n- Requires owners/operators of certain Cessna 150/152 family aeroplanes to check the forward attachment area of the horizontal stabiliser for signs of cracking or structural distress. (Applicability; Requirement)\n- The required checks are: gain access to the forward attachment area; visually inspect the nutplates for cracking or structural distress; visually inspect the stabiliser structure in the attachment area for cracking or structural distress. (Requirement)\n\nWho it affects\n\n- Applies to all A150, A152, FA150, FA152, FRA150 and FRA152 aeroplanes. The immediate obligations fall on the aircraft owner/operator and the maintenance organisation or technician who carries out the Maintenance Release inspections. (Applicability; Requirement)\n\nWhen and how often the checks must be done\n\n- The first inspection must be done within 100 hours time in service after 31 December 1985, or at the next scheduled inspection for the issue of a Maintenance Release after that date, whichever is later. After that, the visual inspection must be performed each time a new Maintenance Release is issued. (Compliance)\n\nWhy it matters (stated purpose and practical implications)\n\n- The stated purpose is to detect cracking in the horizontal stabiliser forward attachment nutplate. (Requirement)\n- The Background explains this amendment aligns the repeat inspection frequency with the periodic Maintenance Release inspection schedule. That alters how inspections are scheduled going forward and makes the AD’s repeat interval coincide with the aircraft’s periodic inspection cycle. (Background)\n\nWho pays and who decides\n\n- Owners/operators pay the direct labour and any downtime costs for gaining access and performing the visual inspections, and they bear the cost of any remedial work if cracking or distress is found. (Requirement; Compliance)\n- Maintenance organisations and technicians carry out the inspections and decide whether access or disassembly is needed to complete the visual checks. The regulator (Civil Aviation Safety Authority) enforces compliance with the AD. (Applicability; Requirement; Compliance)\n\nIncentives, compliance burden and discretion\n\n- Incentives: Operators have an incentive to detect and fix cracking early to avoid structural failure and potential greater repair costs; aligning the AD inspection with the Maintenance Release can reduce separate scheduling burdens. (Background; Compliance)\n- Compliance burden: The AD mandates gaining access and performing visual inspections at each Maintenance Release, creating a recurring, operational task for owners/operators and maintenance providers. Gaining access may require additional labour or partial disassembly. (Requirement)\n- Discretion: The AD prescribes visual inspection steps; there is limited regulatory discretion in whether the checks must be done, but technicians retain professional judgement over how to gain access and whether additional inspection or repair is required if damage is suspected. (Requirement)\n\nTrade-offs, limits and implementation risk\n\n- Trade-offs: Tying the AD inspections to Maintenance Release timing reduces the need for a separate inspection schedule but may lengthen the interval between inspections compared with the previous repeat interval (the Background states the repeat inspection frequency is extended to coincide with periodic inspections). (Background)\n- Limits of the mandated method: The AD specifies visual inspection only. Visual checks can miss subsurface or small fatigue cracks; detecting those may require more invasive inspection or non‑destructive testing, which the AD does not mandate. (Requirement)\n- Implementation risk: If access is difficult or if visual inspection standards vary between technicians, cracks could be missed; if cracks are found, the AD text does not specify corrective actions, so additional maintenance decisions and costs will follow. (Requirement)\n\nConcrete behavioural change\n\n- Operators must incorporate the specified visual checks into the Maintenance Release inspection routine for the listed Cessna models, and maintenance providers must perform these checks and report/act on any findings at each Maintenance Release. (Requirement; Compliance)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a minor amendment to an existing airworthiness directive. The original directive required inspections for cracking in the horizontal stabiliser attachment. Amendment 1 simply adjusts the repeat inspection frequency to align with existing maintenance schedules (Maintenance Release inspections) rather than imposing a separate timeline. The scope remains tightly focused on the original safety issue."},"complexity_factors":["Very short document (under 300 words)","Only 6 defined models in applicability section","Simple procedural requirements (3 numbered steps)","Single compliance deadline with straightforward alternative timing","No cross-references to other legislation or regulations","No conditional logic or nested exceptions","Plain language background explanation"],"plain_english_summary":"This is a **safety directive** (called an \"Airworthiness Directive\") issued by Australia's aviation safety regulator (CASA) that applies to specific **Cessna light aircraft models** (the 150 and 152 series, including some French-built variants).\n\n**What it requires:**\nOwners and operators of these planes must **inspect a specific part of the tail** — the forward attachment point where the horizontal stabiliser (the small wing at the back that keeps the plane level) connects to the fuselage.\n\nSpecifically, they must:\n- **Open up** the inspection area to get access\n- **Visually check** the nutplates (metal plates with threaded holes that bolts screw into) for cracks or damage\n- **Visually check** the surrounding structure for cracks or damage\n\n**When to do it:**\n- **First time:** Within 100 flying hours after 31 December 1985, or at the next scheduled inspection for the plane's Maintenance Release (a certificate showing the aircraft is safe to fly) — whichever comes later\n- **Ongoing:** Every time the plane gets a new Maintenance Release\n\n**Why it matters:**\nCracks in this attachment point could cause the horizontal stabiliser to fail in flight, potentially leading to loss of control. This directive was **updated (Amendment 1)** to make the repeat inspections less frequent — instead of a separate deadline, they now happen during regular scheduled maintenance checks."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment","history":"/api/acts/ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment/history","analysis":"/api/acts/ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment/analysis","conflicts":"/api/acts/ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment/conflicts","importantCases":"/api/acts/ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment/important-cases","documents":"/api/acts/ad-cessna-150-32-amdt-1-horizontal-stabiliser-forward-attachment/documents"}}