{"id":"F2006B02191","name":"AD/AC-112/7 Amdt 2 - Lower Vertical Fin Rib - Inspection","slug":"ad-ac-112-7-amdt-2-lower-vertical-fin-rib-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41421,"registerId":"commonwealth-F2006B02191-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC-112/7 Amdt 2 - Lower Vertical Fin Rib - Inspection","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)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AC \\-112/7 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nGulfstream (Rockwell) 112 Series Aeroplanes\n\nAD/AC-112/7\n\nAmdt 2\n\n  \nLower Vertical Fin Rib \\- Inspection 7/2002\n\nApplicability: All models 112 and 112B with S/Nos. 3 to 544; All model 112TC with S/Nos. 13000 to 13108; All model 112TCA with S/Nos. 13150 to 13309.\n\nRequirement: Action in accordance with Commander Aircraft Company Service Bulletin (SB) No.\n\nSB-112-56B.\n\nNote: Aircraft modified per Gulfstream Aerospace Service Bulletins SB-112-56 or SB-112-56A are not in compliance with this Airworthiness Directive.\n\nCompliance: Unless already accomplished inspect within 100 hours’ time in service after 11 July 2002 and thereafter at intervals not exceeding 100 hours’ time in service until modified.\n\nThis Airworthiness Directive becomes effective on 11 July 2002.\n\nBackground: The Amendment 1 of this directive was issued to require inspection of the lower vertical fin rib during the 100 hour inspection period for cracking as required by the manufacturer’s airplane maintenance manual.\n\nAmendment 2 is issued to reflect an amendment to the manufacturers service bulletin, which increases the applicability range and an improved repair scheme when cracks are found.\n\nAmendment 1 of this Airworthiness Directive became effective in July 1978.\n\n![](image.002.jpeg)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 31 May 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 19 June 2002.\n\n  \nPage 1 of 1","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 2 broadened scope by increasing the applicability range and updated the service bulletin with an improved repair scheme. The background states: 'Amendment 2 is issued to reflect an amendment to the manufacturers service bulletin, which increases the applicability range and an improved repair scheme when cracks are found.' This expands the set of affected aircraft and alters the corrective instructions operators must follow (Requirement: SB-112-56B; Background)."},"complexity_factors":["Narrow technical focus on a specific structural item (lower vertical fin rib) — low subject-matter breadth","Applicability limited by precise serial-number ranges (multiple model/serial blocks)","Cross-reference to external maintenance instruction: Commander SB-112-56B (operators must follow that SB)","Recurring compliance requirement: inspection every 100 hours until modification (ongoing operational burden)","Exception note: aircraft modified per Gulfstream SB-112-56 or SB-112-56A are stated as 'not in compliance' — creates conformity ambiguity","Revocation of earlier AD and regulatory basis cited (subreg 39.1(1)) — procedural history to track"],"plain_english_summary":"Requires operators of Gulfstream (Rockwell) 112-series aeroplanes within specified serial-number ranges to inspect the lower vertical fin rib for cracking per Commander Service Bulletin SB‑112‑56B. The first inspection must occur within 100 hours’ time in service after 11 July 2002 and repeat every 100 hours until the aeroplane is modified. Aircraft modified per Gulfstream SB‑112‑56 or SB‑112‑56A are not compliant with this AD. CASA issued the directive under CAR 1998 subregulation 39.1(1)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"The original 1978 directive required inspection of the lower vertical fin rib for cracking. Amendment 2 (2002) has expanded the scope in two ways: (1) it increases the range of aircraft serial numbers covered ('increases the applicability range'), bringing more aircraft under the safety order; and (2) it introduces an 'improved repair scheme' rather than merely requiring inspections, effectively changing the directive from a pure inspection regime to one that also mandates specific remedial action standards."},"complexity_factors":["Single page document with straightforward applicability criteria (specific aircraft models and serial numbers)","Only one substantive requirement: follow a referenced manufacturer service bulletin","Simple compliance timeline (100 hours time-in-service, repeating)","Minimal cross-referencing (only to the manufacturer's SB-112-56B and explicit exclusion of two prior bulletins)","Clear background explanation of why the amendment was made","No nested definitions, conditional logic, or exceptions beyond the explicit exclusion of prior modifications"],"plain_english_summary":"This safety order requires owners/operators of specified Gulfstream/Rockwell Commander 112-series aeroplanes to inspect the lower vertical fin rib for cracks every 100 flight hours and to follow Service Bulletin SB-112-56B exactly, using its improved repair scheme if cracks are found and continuing inspections until a permanent modification is installed. It updates and expands coverage from the prior order because undetected cracks could cause catastrophic tail failure; earlier fixes under older bulletins are not considered compliant."},"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-112-7-amdt-2-lower-vertical-fin-rib-inspection","history":"/api/acts/ad-ac-112-7-amdt-2-lower-vertical-fin-rib-inspection/history","analysis":"/api/acts/ad-ac-112-7-amdt-2-lower-vertical-fin-rib-inspection/analysis","conflicts":"/api/acts/ad-ac-112-7-amdt-2-lower-vertical-fin-rib-inspection/conflicts","importantCases":"/api/acts/ad-ac-112-7-amdt-2-lower-vertical-fin-rib-inspection/important-cases","documents":"/api/acts/ad-ac-112-7-amdt-2-lower-vertical-fin-rib-inspection/documents"}}