{"id":"F2006B04932","name":"AD/CESSNA 150/34 - Flap Actuator Screw Mechanical Stop","slug":"ad-cessna-150-34-flap-actuator-screw-mechanical-stop","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44777,"registerId":"commonwealth-F2006B04932-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CESSNA 150/34 - Flap Actuator Screw Mechanical Stop","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)  Cessna 150, F150, 152 & F152 Series Aeroplanes\n\n \n\nAD/CESSNA 150/34 Flap Actuator Screw Mechanical Stop 3/80\n\nApplicability: Models 152 and A152 with S/Nos. 15279406 to 15284080, A1520735 to A1520919, F15201429 to F15201798 and FA1520337 to FA15200372.\n\n \n\nRequirement: Action in accordance with Cessna SIL No. SE 79-57.\n\n \n\nNote: FAA AD 80-01-06, Amendment 39-3649 refers.\n\n \n\nCompliance: Within 100 hours time in service after 31 March 1980.\n\n \n\nBackground: A mechanical stop is now available to prevent overtravel of the flap actuator assembly. Overtravel may lead to an asymmetric flap condition.\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\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"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 specific aircraft. It has not expanded beyond its original purpose of mandating a flap actuator modification."},"complexity_factors":["Very short document (under 200 words)","Only 4 defined elements: applicability by specific serial numbers, one compliance deadline, one reference to external technical document (Cessna SIL), and one cross-reference to FAA AD","Single unconditional requirement with no exceptions or nested conditions","No internal cross-references or defined terms section","Straightforward temporal compliance trigger (100 hours time in service after fixed date)"],"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) for specific Cessna aircraft.\n\n**What it does:** It requires owners and operators of certain Cessna 152 and A152 aeroplanes to install a mechanical stop on the flap actuator screw. This stop prevents the flaps (the movable surfaces on the wings that help with takeoff and landing) from moving too far and becoming uneven on each side — a condition called \"asymmetric flaps\" that can make the plane hard or dangerous to control.\n\n**Who it affects:** Owners and operators of specific Cessna 152 and A152 models with serial numbers in the listed ranges (roughly late 1970s production aircraft).\n\n**What must be done:** Follow the instructions in Cessna Service Information Letter (SIL) No. SE 79-57 to install the mechanical stop.\n\n**When it must be done:** Within 100 hours of flying time after 31 March 1980.\n\n**Why it matters:** Without this fix, the flaps could overtravel and become lopsided, potentially causing loss of control during critical phases of flight like landing."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Based only on the text provided, the AD sets a clear, limited scope by model and serial-number ranges (Applicability) and prescribes a single corrective modification (Requirement). The document contains no indication that the scope has been altered from its original specification; it defines the affected population and the required action without amendments noted in the text."},"complexity_factors":["Narrow, serial-number-limited applicability reduces legal and operational scope (Applicability).","Requirement delegates technical procedure to an external manufacturer service instruction (Cessna SIL No. SE 79-57), so implementers must consult and follow that document (Requirement).","Fixed compliance deadline (100 hours after 31 March 1980) creates a scheduling constraint and operational burden (Compliance).","Cross-reference to an FAA AD means implementers may need to reconcile multiple documents for context, but the AD's core requirement is simple (Note).","Technical work requires qualified maintenance skills and parts; legal text does not specify parts/costs, increasing reliance on secondary technical documentation (Requirement)."],"plain_english_summary":"This AD mandates fitting a mechanical stop on the flap-actuator screw of specified Cessna 152/A152 serial numbers, to be installed per Cessna Service Instruction SE 79-57. It’s intended to prevent actuator overtravel and the resulting asymmetric flap condition. Registered owners/operators must arrange and pay for the work within 100 hours TIS after 31 March 1980; compliance follows the manufacturer's instruction and referenced FAA AD."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cessna-150-34-flap-actuator-screw-mechanical-stop","history":"/api/acts/ad-cessna-150-34-flap-actuator-screw-mechanical-stop/history","analysis":"/api/acts/ad-cessna-150-34-flap-actuator-screw-mechanical-stop/analysis","conflicts":"/api/acts/ad-cessna-150-34-flap-actuator-screw-mechanical-stop/conflicts","importantCases":"/api/acts/ad-cessna-150-34-flap-actuator-screw-mechanical-stop/important-cases","documents":"/api/acts/ad-cessna-150-34-flap-actuator-screw-mechanical-stop/documents"}}