{"id":"F2006B10209","name":"AD/GAF-N22/60 - Horizontal Stabiliser Pivot Bearings and Brackets","slug":"ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55867,"registerId":"commonwealth-F2006B10209-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GAF-N22/60 - Horizontal Stabiliser Pivot Bearings and Brackets","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-N22/60 Horizontal Stabiliser Pivot Bearings and Brackets\n\n\n8/90 T\n\n \n\nApplicability: Nomad series aircraft with S/Nos N22S-159 to N22S-165 inclusive and S/No N22C- 69 fitted with tailplane S/No GAF-179.\n\n \n\nRequirement: Action in accordance with ASTA Nomad Alert SB ANMD 55-27 dated 21 May 1990. Compliance:               Prior to further flight after 6 June 1990.\n\nBackground: With the fitting of Modification 663 the pivot bolts for the horizontal stabilizer are changed. Excessive stress may be placed on the tailplane pivot brackets by tightening the nuts on the pivot bolts, if insufficient shims are fitted.\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":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive enforces a specific corrective action set out by the manufacturer's service bulletin for aircraft modified under Modification 663 and applies only to particular serial-numbered aircraft. It does not expand or widen the group of affected aircraft beyond those listed nor introduce additional regulatory objectives beyond addressing the pivot-bolt/shim stress issue described in the Background (Applicability; Requirement; Background)."},"complexity_factors":["Narrow applicability limited to a small set of serial numbers (Applicability).","Mandates following an external technical document (ASTA Nomad Alert SB ANMD 55-27) rather than setting out technical steps in the AD (Requirement).","Immediate compliance deadline (must be done prior to further flight after 6 June 1990) creates time sensitivity (Compliance).","Technical work requires maintenance capability, parts (shims) and access to the service bulletin — practical, not legal, complexity (Requirement; Background).","Short, self-contained AD text with minimal statutory detail reduces legal complexity."],"plain_english_summary":"CASA requires owners/operators of specific GAF Nomad N22/N24 serial numbers to carry out the actions in ASTA Nomad Alert Service Bulletin ANMD 55-27 (21 May 1990) before the aircraft may fly again after 6 June 1990. \n\nThe work (inspection/adjustment per the bulletin) addresses potential excessive stress on tailplane pivot brackets after Modification 663; affected owners/operators pay for parts and labour and must ground aircraft until compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a limited fleet. It has not expanded beyond its original purpose of mandating inspection/repair of horizontal stabiliser pivot hardware on affected Nomad aircraft."},"complexity_factors":["Single, highly specific applicability clause limiting to 8 specific aircraft serial numbers plus one tailplane serial number","Single mandatory action referencing an external technical document (Service Bulletin ANMD 55-27)","No defined terms section — uses standard aviation terminology","No conditional logic, exceptions, or nested provisions","Straightforward compliance deadline (prior to further flight after fixed date)","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) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of certain **GAF Nomad aircraft** (specific serial numbers N22S-159 through N22S-165, and N22C-69, fitted with tailplane serial number GAF-179) to inspect and fix a problem with the **horizontal stabiliser pivot bearings and brackets** — the parts that connect the tail's horizontal wing to the aircraft body.\n\n**The safety problem:**\nWhen a specific modification (Modification 663) was installed, it changed the pivot bolts. If mechanics didn't add enough shims (thin metal spacers) when tightening the nuts on these bolts, it could put **excessive stress on the tailplane brackets** — potentially leading to structural failure.\n\n**What must be done:**\nFollow the instructions in **ASTA Nomad Alert Service Bulletin ANMD 55-27** (dated 21 May 1990) before flying the aircraft again after 6 June 1990.\n\n**Who it affects:**\nOwners and operators of a very specific subset of GAF N22/N24 Nomad aircraft — a twin-turboprop utility aircraft originally built by the Australian Government Aircraft Factories.\n\n**Why it matters:**\nThis is a **flight-critical safety issue**. The horizontal stabiliser controls the aircraft's pitch (nose up/down). If the pivot brackets fail due to improper installation stress, the pilot could lose control of the aircraft. The directive makes compliance mandatory before further flight."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets","history":"/api/acts/ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets/history","analysis":"/api/acts/ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets/analysis","conflicts":"/api/acts/ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets/conflicts","importantCases":"/api/acts/ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets/important-cases","documents":"/api/acts/ad-gaf-n22-60-horizontal-stabiliser-pivot-bearings-and-brackets/documents"}}