{"id":"F2006B02160","name":"AD/AC/99 - Wing and Fuselage Structure","slug":"ad-ac-99-wing-and-fuselage-structure","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41390,"registerId":"commonwealth-F2006B02160-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 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\n![](image.001.png)  \n\nTwin Commander (Gulfstream/Rockwell/Aerocommander 500, 600 and 700) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/AC/99 Wing and Fuselage Structure 7/2","sectionType":"part","heading":"AD/AC/99 Wing and Fuselage Structure 7/2003","content":"# AD/AC/99 Wing and Fuselage Structure 7/2003\n\nApplicability: Model 690D aircraft, serial numbers 15001 through 15036, and 15038 through 15040.\n\nModel 695A aircraft, serial numbers 96001 through 96062, 96065 through 96068,\n\n96070, 96071, 96073, 96074, 96076, 96077, 96079 through 96084, 96086, 96087,\n\nand 96089 through 96100.\n\nModel 695B aircraft, serial numbers 96063, 96069, 96075, 96078, 96085, and 96204\n\nthrough 96208.\n\nRequirement: 1. Initially inspect and modify the wing and fuselage areas (Part I Inspection\n\n/Modifications as identified in Twin Commander Aircraft Corporation Mandatory Service Bulletin (MSB) No. 214, dated 26 January 2000) and repetitively inspect with necessary modification or replacement of damaged parts (Part II Recurring Inspections as identified in MSB No. 214, in accordance with the following schedules:\n\n    Part I Initial Inspections/Modifications: Initially (unless already accomplished) accomplish the Part I Inspections/Modifications at whichever compliance time in Requirement 1.a.(i) or 1.a.(ii) occurs later:\n\n    (i) The compliance times presented in Part I Table I of MSB No. 214 as amended by; Twin Commander Corporation Service Publications (SP) revision notice to MSB No. 214, Revision 1, Release Date: 19 April 2000; and SP revision notice to MSB No. 214, Revision 2, Release Date: 21 May 2001; or,\n\n    (ii) MSB 214 Table A Compliance Times.\n    b. Part II Recurring Inspections: Repetitively inspect as referenced in Part II Recurring Inspections on page 62 of MSB No. 214 as amended by; SP revision notice to MSB No.214, Revision 1; and SP revision notice to MSB No. 214, Revision 2.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This appears to be a standard airworthiness directive maintaining its original scope: mandating specific safety inspections and modifications for identified aircraft models. There is no evidence of scope creep beyond the original safety purpose."},"complexity_factors":["Multiple document references required: operators must cross-reference MSB No. 214 plus two separate revision notices (Revision 1 dated 19 April 2000 and Revision 2 dated 21 May 2001)","Nested compliance timing structure: Requirement 1.a.(i) OR 1.a.(ii) with 'whichever occurs later' logic","Precise serial number applicability with numerous gaps and ranges (e.g., '96001 through 96062, 96065 through 96068, 96070...') requiring careful verification","Two-phase compliance structure: Part I (initial one-time actions) and Part II (ongoing recurring inspections)","Specific page reference for recurring inspections ('page 62 of MSB No. 214') creating dependency on external document pagination","Incorporation by reference of manufacturer service publications rather than setting out requirements directly in the AD text"],"plain_english_summary":"This AD requires owners/operators of certain Twin Commander 690D/695A/695B aircraft (specified serial numbers) to inspect and modify wing and fuselage structure per the manufacturer’s service bulletin (MSB No. 214, as revised) to address known structural defects.\n\nCompliance requires initial modifications and recurring inspections/repairs. It’s legally mandatory to prevent potentially catastrophic wing or fuselage failure."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The AD remains narrowly targeted to specified serial-number ranges of Twin Commander Model 690D, 695A and 695B aircraft and continues to require initial and recurring inspections/modifications to wing and fuselage areas. The version shown updates which MSB revision notices and tables are incorporated by reference and clarifies the compliance timing rule, but does not expand the set of affected aircraft or add new categories of action beyond inspections, modifications and part replacement contained in MSB No. 214."},"complexity_factors":["Applicability limited to multiple explicit serial-number ranges across three models (increases tracking complexity for operators)","External cross-references to a manufacturer Mandatory Service Bulletin (MSB No. 214) rather than full technical text in the AD","Two separate MSB revision notices incorporated by reference (Revision 1 and Revision 2) with specific release dates","Alternative timing rule for initial action: 'whichever occurs later' between two different MSB tables (Part I Table I as amended, or MSB 214 Table A)","Recurring inspections referenced to a specific page (Part II, page 62) in the MSB, creating a single-page dependency","Conditional language ('unless already accomplished') that requires verification of prior work history","Scope limited but procedural: repeated inspections and possible part replacement create ongoing compliance monitoring"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an Airworthiness Directive (AD) that orders specific inspections and any required repairs or modifications to the wing and fuselage on certain Twin Commander aeroplanes.  (An AD is a mandatory safety requirement issued by the regulator.)\n\n- It applies only to the listed serial-number ranges of Model 690D, Model 695A and Model 695B Twin Commander aircraft (see the Applicability section).\n\n- The AD requires two things (Requirement 1):\n  - Part I — an initial inspection and any modification of the wing and fuselage areas, carried out in accordance with Twin Commander Mandatory Service Bulletin (MSB) No. 214 and the MSB revision notices identified in the AD; and\n  - Part II — recurring inspections and any necessary modification or replacement of damaged parts, carried out in accordance with the Part II recurring inspection schedule in MSB No. 214 (page 62) as amended by the same revision notices.\n\n- Timing: For the initial (Part I) work you must comply at whichever time is later of these two: (i) the compliance times listed in Part I Table I of MSB No. 214 as amended by the two named Service Publication (SP) revision notices; or (ii) the compliance times in MSB 214 Table A. The recurring inspections follow the schedule in Part II (page 62) as amended.\n\n**Who this affects**\n\n- Owners and operators of the specifically listed Twin Commander Model 690D, 695A and 695B aircraft identified by serial number.  \n- Maintenance organisations and technicians who perform inspections, modifications and parts replacement for those aircraft.  \n- Suppliers of replacement parts or modification kits for the affected structure.\n\n**Why it matters (the regulator's stated purpose, and the practical effects)**\n\n- The regulator issues the AD to correct an identified unsafe condition in the wing/fuselage structure. The AD fixes how and when the unsafe condition must be inspected and corrected by mandating compliance with Twin Commander MSB No. 214 and its revision notices (Requirement 1 and Applicability).\n\n- Who pays: the aircraft owners/operators pay for inspections, any required structural modifications or parts replacement, and downtime while work is done.\n\n- Who decides technical detail: Twin Commander MSB No. 214 (and its revision notices) sets the technical inspection steps, modification work and compliance schedules; CASA enforces the requirement by referencing those documents in the AD.\n\n- Behaviour changes required: owners will need to schedule and complete the initial structural inspection/modification if not already done, and then schedule recurring inspections per the MSB. Non-compliance can lead to grounding or regulatory action.\n\n**Trade-offs, implementation risks and compliance burdens**\n\n- Compliance burden: the AD delegates the technical method and timing to an externally issued manufacturer MSB and its revision notices; operators must obtain and follow those documents precisely. Costs and downtime depend on findings from the inspections and whether structural repairs or part replacements are needed.\n\n- Implementation risks: the AD relies on cross-referenced MSB tables and amendment notices. That creates potential for confusion about the correct version or table to use (see Requirement 1.a.(i)–(ii) and Requirement 1.b). If an operator uses the wrong MSB revision, they risk non‑compliance.\n\n- Effects on private choice and markets: certified maintenance organisations will receive work to perform inspections/repairs; parts suppliers may see demand for affected structural components. Some owners may choose to restrict operations, defer sales, or retire affected airframes if repair costs or downtime are high.\n\n- Concentrated benefits and diffuse costs: the safety benefits accrue to all who fly or are near the affected aircraft (diffuse), while the direct costs fall on the relatively small group of listed aircraft owners/operators (concentrated). The AD does not create a new subsidy or fee; it imposes a privately borne compliance cost.\n\n**Section citations (where the mechanics appear in the AD text)**\n- Applicability: lists exact models and serial numbers.\n- Requirement 1 (Parts I and II): prescribes initial and recurring inspections/modifications and references MSB No. 214 and specified SP revision notices.\n- Requirement 1.a.(i)–(ii) and 1.b: set the compliance timing rules and identify the externally referenced tables/page (Part I Table I, MSB Table A, Part II page 62).\n\n**Bottom line**: The AD mandates that owners/operators of the narrowly specified Twin Commander airframes carry out initial structural inspections/modifications and recurring inspections according to Twin Commander MSB No. 214 (as amended). It shifts technical detail to the manufacturer MSB, creates a private compliance cost (inspections, repairs, downtime), and requires careful attention to the MSB version and tables named in the AD."},"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-99-wing-and-fuselage-structure","history":"/api/acts/ad-ac-99-wing-and-fuselage-structure/history","analysis":"/api/acts/ad-ac-99-wing-and-fuselage-structure/analysis","conflicts":"/api/acts/ad-ac-99-wing-and-fuselage-structure/conflicts","importantCases":"/api/acts/ad-ac-99-wing-and-fuselage-structure/important-cases","documents":"/api/acts/ad-ac-99-wing-and-fuselage-structure/documents"}}