{"id":"F2006B02153","name":"AD/AC/92 - Wing Skin Near Main Landing Gear","slug":"ad-ac-92-wing-skin-near-main-landing-gear","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41383,"registerId":"commonwealth-F2006B02153-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC/92 - Wing Skin Near Main Landing Gear","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)  \nTwin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes\n\nAD/AC/92 Wing Skin Near Main Landing Gear 6/95\n\nApplicability: All models except 690C and all 695 series. Requirement: 1. Location:\n\nWith your head up inside the wheel well you will see the heavy forgings which contain the bushings for the main landing gear trunnion. Note that each forging has two fingers which poke up through cutouts in the lower surface of the wing. It is the forward cutouts which are to be inspected for cracks.\n\n    2. Inspection from Underneath:\n\nClean the external skin around each forward cutout. With a mirror and a strong light, look for cracks in the external skin near the forward and aft radii of each forward cutout. (The aft radius may be hard to see.)\n\n    3. Inspection from the Top:\n\nRemove the access panel in the top of the nacelle, then the underlying access panel in the top of the wing, to view the forward cutouts from inside the wing. With a mirror and a strong light, look for cracks in the internal doubler near the forward and aft radii of each forward cutout.\n\nCompliance: Inspect at the next periodic inspection after 25 May 1995.\n\nIf not cracked, repeat the inspection every 1000 or fewer hours, or every 500 or fewer hours while the aircraft is flying low level surveys.\n\nIf only the skin is cracked, or if the crack in the doubler can be smoothly dressed out and dye checked without removing more than 6 mm from the edge, and if the skin crack has not grown past the nearest rivet, the aircraft may remain in service for up to 500 hours if the crack is re-inspected every 250 or fewer hours, or every 125 or fewer hours while the aircraft is flying low level surveys. The area must be repaired before further flight if the skin crack has grown beyond the nearest rivet, or a doubler crack cannot be dressed out as just described.\n\nBackground: Two aeroplanes have been found with cracks at cutouts in the lower surface of the wing. Both aeroplanes were 500S models, and both were flying low level surveys, however there is no reason to believe that other Aero Commanders with a similar wing won’t suffer the same problem. The cracks might be missed during routine maintenance, so special inspections have been specified to prevent major cracking and loss of wing strength.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific structural defect in a defined aircraft fleet. The scope remains precisely limited to wing skin inspections for Twin Commander aircraft as originally intended."},"complexity_factors":["Simple conditional logic with clear thresholds (6mm removal limit, 500-hour extension, rivet proximity test)","Two alternative inspection methods provided (external and internal)","Straightforward applicability statement with explicit exclusions","No cross-references to other legislation or regulations","Limited defined terms (only standard aviation terminology like 'doubler', 'trunnion', 'dye checked')","Single compliance pathway with nested but clear conditions for continued operation with defects"],"plain_english_summary":"This CASA Airworthiness Directive mandates special inspections of the wing skin at the main landing‑gear attachment on Twin Commander 500/600/700 series (excluding 690C and 695 series). Owners/operators must inspect externally (clean, mirror/light) or internally (remove access panels to check doublers) at the next scheduled maintenance after 25 May 1995, with repeat intervals (1,000 fh; 500 fh for low‑level survey). Minor cracks allow limited continued flight with tighter checks; serious cracks require grounding and repair. It follows two survey‑related crack incidents."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive's scope is as stated in the text: it applies to the specified Twin Commander models (excluding 690C and 695 series) and limits action to inspections, monitoring under strict conditions, and mandatory repair when limits are exceeded. The instrument does not indicate any expansion or narrowing of that scope."},"complexity_factors":["Targeted applicability (all Twin Commander models except 690C and 695 series) requiring checking fleet identity before action","Two access routes for inspection: external (underwing) and internal (remove nacelle and wing access panels)","Multiple interval rules: initial compliance date (next periodic after 25 May 1995), routine repeat intervals, and shorter intervals for low‑level survey operations","Conditional temporary relief: allowance to remain in service with small/dressable cracks subject to tight size limits (≤6 mm removed at edge) and re‑inspection schedules","Objective but technical criteria for decision‑making (crack growth past nearest rivet; ability to 'dress out' and dye‑check) requiring maintenance judgement","Immediate mandatory repair trigger if crack exceeds limits (repair before further flight), creating operational disruption risk","Practical requirements for tools/skills (mirror, strong light, dye‑check) and access panel removal increase labour and downtime"],"plain_english_summary":"Requires inspections of the wing skin and internal doubler at the forward cutouts around the main landing‑gear trunnion on Twin Commander aeroplanes (all models except 690C and 695 series). \n\nOperators must inspect from beneath and from inside (remove access panels) at the next periodic check after 25 May 1995 and at specified hourly intervals — with shorter intervals for low‑level survey work. Minor, dressable cracks may be temporarily monitored under strict size and re‑inspection limits; repairs are mandatory if cracks exceed those limits. Operators pay inspection and repair costs; maintenance crews decide serviceability."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-92-wing-skin-near-main-landing-gear","history":"/api/acts/ad-ac-92-wing-skin-near-main-landing-gear/history","analysis":"/api/acts/ad-ac-92-wing-skin-near-main-landing-gear/analysis","conflicts":"/api/acts/ad-ac-92-wing-skin-near-main-landing-gear/conflicts","importantCases":"/api/acts/ad-ac-92-wing-skin-near-main-landing-gear/important-cases","documents":"/api/acts/ad-ac-92-wing-skin-near-main-landing-gear/documents"}}