{"id":"F2006B10225","name":"AD/GAF-N22/75 Amdt 1 - Horizontal Stabiliser Access Panel Intercostal Angles and Upper and Lower Skins","slug":"ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55883,"registerId":"commonwealth-F2006B10225-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GAF-N22/75 Amdt 1 - Horizontal Stabiliser Access Panel Intercostal Angles and Upper and Lower Skins","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), 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/GAF N22/75 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\nGAF N22 and N24 Series Aeroplanes\n\nAD/GAF-N22/75\n\nAmdt 1\n\n  \n\nHorizontal Stabiliser Access Panel Intercostal Angles and Upper and Lower Skins\n\n  \n10/2001\n\nApplicability: Model N22 and N24 aircraft with line sequence numbers listed in the Requirement document.\n\nRequirement: Inspect in accordance with ASTA Nomad Service Bulletin NMD-55-34 Revision 1\\. Compliance: At the next 100 hour inspection after 18 July 1996 or before 12 September 1996,\n\nwhichever occurs first. Thereafter at intervals not to exceed 100 hours time in service or 12 calendar months, whichever occurs first.\n\nThe compliance times of the original issue of this Directive remain unchanged by this issue.\n\nThis amendment becomes effective on 4 October 2001.\n\nBackground: Reports were received by the manufacturer of cracking of the horizontal stabiliser upper and lower skin, at the ends of the horizontal stabiliser access hole intercostal angles and in the horizontal stabiliser trailing edge channel.\n\nAmendment 1 introduces a revision of the Requirement document, which was issued to provide for replacing rivets with screws in the access panels and to clarify figures.\n\nThe original issue of this Airworthiness Directive became effective on 18 July 1996.\n\n![](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 22 August 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 12 September 2001.\n\n  \nPage 1 of 1","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 revises the Requirement document to specify replacing access‑panel rivets with screws and to clarify figures, altering the required repair method and instructions. The set of affected aircraft (applicability line sequence numbers) and the compliance timing framework remain unchanged, so the population covered is the same while the mandated corrective action and instructions have been modified."},"complexity_factors":["Reference to an external technical document (ASTA Nomad Service Bulletin NMD‑55‑34 Rev 1) — requires operators to obtain and follow the service bulletin (Requirement).","Applicability limited to specific line sequence numbers — operators must check serial/line lists to determine if an aircraft is affected (Applicability).","Dual compliance triggers (next 100‑hour or fixed calendar deadline, then 100 hours or 12 months) — creates scheduling and record‑keeping complexity (Compliance).","Physical modification detail (replace rivets with screws) — requires parts, appropriate tooling and competent maintenance personnel; adds supply and labour cost (Amendment 1; Background).","Structural safety focus (skin and intercostal cracking) — inspection and repair are safety‑critical, increasing inspection rigor and potential downtime (Background; Requirement).","Regulatory cross‑reference to CAR subregulation 39.1(1) — legal enforcement mechanism and delegated decision‑making (preamble).","No change to original compliance times — preserves existing maintenance cycle but may require retroactive action for past due items (Compliance)."],"plain_english_summary":"This Airworthiness Directive requires operators of specified GAF N22 and N24 aeroplanes to inspect the horizontal stabiliser access‑panel intercostal angles and the upper and lower stabiliser skins in accordance with ASTA Nomad Service Bulletin NMD‑55‑34 Rev 1, and where directed replace access‑panel rivets with screws. CASA’s delegate issues and enforces the AD; aircraft operators must schedule the inspection at the next 100‑hour check (or by 12 Sept 1996) and then every 100 hours or 12 months, bearing the cost and carrying out any modifications."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The amendment maintains identical scope to the original 1996 directive. It updates only the technical implementation details (replacing rivets with screws for access panels and clarifying figures) while preserving the same aircraft applicability, inspection requirements, and compliance timing. The explicit statement that 'The compliance times of the original issue of this Directive remain unchanged' confirms no scope expansion."},"complexity_factors":["Single, clearly defined applicability (two specific aircraft models with listed serial numbers)","One primary requirement referencing an external technical document (Service Bulletin NMD-55-34 Rev 1)","Straightforward compliance schedule with two alternative triggers (100 hours OR 12 months)","Minimal conditional logic — only 'whichever occurs first' clauses","Short document (approximately 300 words) with no defined terms section","No nested exceptions or cross-references to other legislation beyond the enabling regulation (CAR 1998 subreg 39.1(1))","Amendment is administrative — updates referenced technical document without changing substantive requirements"],"plain_english_summary":"This AD revokes and replaces an earlier order, mandating inspections of the horizontal stabiliser on specified GAF N22/N24 aircraft to detect cracking around upper and lower access panels. It affects owners/operators of those serial-numbered Nomads and requires inspections per Service Bulletin NMD-55-34 Rev 1, with the initial check by Sept 1996 or at the next 100‑hr inspection and repeats every 100 hours or 12 months.\n\nThe amendment mainly updates technical detail (allowing screws instead of rivets and clarifying diagrams) while keeping the inspection requirement to prevent structural failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins","history":"/api/acts/ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins/history","analysis":"/api/acts/ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins/analysis","conflicts":"/api/acts/ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins/conflicts","importantCases":"/api/acts/ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins/important-cases","documents":"/api/acts/ad-gaf-n22-75-amdt-1-horizontal-stabiliser-access-panel-intercostal-angles-and-upper-and-lower-skins/documents"}}