{"id":"F2006B08538","name":"AD/CHA/12 Amdt 1 - Wing Ribs","slug":"ad-cha-12-amdt-1-wing-ribs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51312,"registerId":"commonwealth-F2006B08538-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CHA/12 Amdt 1 - Wing Ribs","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)  \nAmerican Champion (Aeronca, Bellanca) Series Aeroplanes\n\nAD/CHA/12\n\nAmdt 1\n\n  \nWing Ribs 10/79\n\nApplicability: All model 8KCAB with S/Nos. 3-70, 4-71, 5-72, 7-72 to 53-72, 54-73 to 119-73 and 120-74 to 159-74 except those which have incorporated Bellanca Kit No 243.\n\nRequirement: Visually inspect the wing ribs for evidence of cracks and/or buckling of the rib flanges as follows:\n\n    (a) Remove the fabric from each of the four doped-on reinforcing rings located on the lower surface of each wing adjacent to the front spar.\n\n    (b) Using a flashlight and mirror inspect all ribs from the first rib outboard of fuel tank and continue through aileron area to last outboard full rib.\n\n    (c) Examine area approximately 2\" aft of front spar (just aft of the rib reinforcement gusset) on the rib top flange for evidence of cracks, distortion and fabric rivet looseness.\n\nIf cracks, distortion or loose fabric rivets are found as a result of the inspection, all damaged ribs are to be repaired to a scheme approved by the Secretary before further flight.\n\nCompliance: At intervals not exceeding 50 hours time in service for normal flight and 10 hours time in service for acrobatic flight.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"As an amendment the instrument specifies precise applicability by serial numbers, prescribes exact inspection steps (fabric removal, flashlight/mirror checks, specific rib range and 2\" aft location), requires Secretary‑approved repair schemes, and sets distinct intervals for normal versus acrobatic use, thereby defining and limiting the AD's operational scope (Applicability; Requirement; Compliance)."},"complexity_factors":["Serial-number-specific applicability increases tracking and applicability checks (Applicability).","Detailed physical procedure requiring removal of doped-on fabric over four reinforcing rings and use of flashlight/mirror (Requirement).","Inspection location precision (approximately 2\" aft of front spar, through fuel-tank to aileron area) raises workmanship and interpretation demands (Requirement).","Repairs must follow a scheme approved by the Secretary, introducing administrative approval and potential delay (Requirement).","Different compliance intervals for normal (50 h) and acrobatic (10 h) operations create dual maintenance schedules (Compliance).","Compliance and repair costs fall on owners/operators and may require specialised labour or facility time (Applicability; Requirement)."],"plain_english_summary":"This directive requires owners/operators of specified American Champion (Aeronca/Bellanca) 8KCAB aeroplanes to inspect wing ribs adjacent to the front spar for cracks, buckling or loose fabric rivets. It directs removing fabric over the doped-on lower reinforcing rings and using a flashlight and mirror to inspect from the first rib outboard of the fuel tank through the aileron area, focusing about 2 inches aft of the front spar.\n\nDefects must be repaired under a Secretary‑approved scheme before further flight. Inspection intervals: 50 hours (normal) and 10 hours (acrobatics). (Applicability; Requirement; Compliance)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a classic single-issue Airworthiness Directive focused on a known structural defect in a specific aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single specific aircraft model and narrow serial number range (approximately 160 aircraft affected)","Straightforward three-step inspection procedure with clear physical descriptions","Simple binary compliance trigger: damage found = ground aircraft until repaired","Two-tier compliance schedule based on flight type (normal vs. acrobatic)","Single exemption condition (Bellanca Kit No. 243 already installed)","No nested definitions, cross-references to other legislation, or conditional exceptions","Document is a standalone operational directive without interpretive sections"],"plain_english_summary":"CASA requires owners of certain American Champion 8KCAB aeroplanes (specific 1970–1974 serials) to inspect wing ribs for cracking, buckling or loose rivets unless Bellanca Kit No. 243 is fitted. The directive mandates fabric removal and internal rib checks at regular intervals (every 50 flight hours, or every 10 hours for aerobatic use). It prevents catastrophic wing failure by grounding aircraft until approved repairs are done."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cha-12-amdt-1-wing-ribs","history":"/api/acts/ad-cha-12-amdt-1-wing-ribs/history","analysis":"/api/acts/ad-cha-12-amdt-1-wing-ribs/analysis","conflicts":"/api/acts/ad-cha-12-amdt-1-wing-ribs/conflicts","importantCases":"/api/acts/ad-cha-12-amdt-1-wing-ribs/important-cases","documents":"/api/acts/ad-cha-12-amdt-1-wing-ribs/documents"}}