{"id":"F2006B10174","name":"AD/GAF-N22/27 - Rudder Tab - Modification","slug":"ad-gaf-n22-27-rudder-tab-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55817,"registerId":"commonwealth-F2006B10174-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GAF-N22/27 - Rudder Tab - Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  GAF N22 and N24 Series Aeroplanes\n\n \n\nAD/GAF-N22/27 Rudder Tab - Modification 8/79\n\nApplicability: All models N22 and N22B not modified in accordance with GAF SB No. NMD-27-3, Rev. 1.\n\n \n\nRequirement: Modify in accordance with GAF SB No. NMD-27-3, Rev. 1.\n\n \n\nNote: The speed of 180 Kts IAS should not be exceeded on aircraft not yet modified.\n\n \n\nCompliance: Before 1 December 1979.\n\n \n\nBackground:  Manufacturer’s tests indicate that wear and backlash which may develop in the rudder tab system during normal service may erode the tab/rudder flutter speed margins.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a single purpose: mandating a specific airframe modification. It has not expanded beyond its original intent."},"complexity_factors":["Single, specific technical requirement referencing an external document (manufacturer's Service Bulletin)","Clear applicability clause identifying affected aircraft by model and exclusion criteria","Simple compliance deadline with no conditional extensions or exceptions","One interim operational limitation (speed restriction) stated in a note","No defined terms section, no cross-references to other legislation, no nested conditions","Total length: approximately 150 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific repairs or modifications to aircraft.\n\n**What it does:**\nOrders owners and operators of certain GAF N22 and N24 series aeroplanes (small aircraft) to modify the rudder tab control system. The modification must follow the manufacturer's Service Bulletin NMD-27-3, Revision 1.\n\n**Why it matters:**\nWear and looseness (\"backlash\") in the rudder tab system can reduce the aircraft's resistance to \"flutter\" — a dangerous vibration that can cause control surfaces to fail at high speeds. This modification prevents potential loss of control.\n\n**Who it affects:**\n- Owners and operators of GAF N22 and N22B aircraft that haven't already been modified per the specified service bulletin\n- Does NOT apply to aircraft already modified per GAF SB No. NMD-27-3, Rev. 1\n\n**Key requirements:**\n- **Must complete by:** 1 December 1979\n- **Interim safety measure:** Until modified, pilots must not exceed 180 knots indicated airspeed (IAS)\n\n**In simple terms:** If you own one of these planes, you must get this specific fix done by the deadline, and fly slower until you do."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD's scope is defined as applying to all GAF N22 and N22B aeroplanes that have not already been modified per the specified service bulletin (Applicability). The instrument does not indicate any expansion or narrowing of that scope within the text; it simply mandates the specified modification (Requirement) and sets a compliance date (Compliance: \"Before 1 December 1979\"). Therefore there is no change of scope indicated in the text."},"complexity_factors":["Narrow applicability: only GAF N22 and N22B models not already modified (Applicability).","Single prescriptive action: modify per a specific manufacturer's service bulletin (Requirement).","Firm compliance deadline with no staged options (Compliance: \"Before 1 December 1979\").","Operational proviso limiting speed until modification is completed (Note: 180 Kts IAS).","Limited technical detail in the AD itself—relies on the referenced service bulletin for implementation (Requirement)."],"plain_english_summary":"This AD requires owners/operators of GAF N22 and N22B aeroplanes to modify the rudder tab system per GAF SB NMD‑27‑3 Rev.1 to restore flutter margin, with a compliance deadline. Until modification is completed the aircraft must not exceed 180 Kts IAS. Operators bear the cost, scheduling and rely on the service bulletin for the technical fix."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gaf-n22-27-rudder-tab-modification","history":"/api/acts/ad-gaf-n22-27-rudder-tab-modification/history","analysis":"/api/acts/ad-gaf-n22-27-rudder-tab-modification/analysis","conflicts":"/api/acts/ad-gaf-n22-27-rudder-tab-modification/conflicts","importantCases":"/api/acts/ad-gaf-n22-27-rudder-tab-modification/important-cases","documents":"/api/acts/ad-gaf-n22-27-rudder-tab-modification/documents"}}