{"id":"F2006B10183","name":"AD/GAF-N22/36 - Horizontal Stabiliser - Modification","slug":"ad-gaf-n22-36-horizontal-stabiliser-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":55828,"registerId":"commonwealth-F2006B10183-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/GAF-N22/36 - Horizontal Stabiliser - 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-N22/36 Horizontal Stabiliser - Modification 4/80\n\nApplicability: All models N22, N22B, N24 and N24A with S/Nos. referenced in SB No.\n\nNMD-55-10.\n\n \n\nDocument: GAF SB No. NMD-55-10.\n\n \n\nCompliance: Before 1 August 1980.\n\n \n\nBackground:  In several cases the horizontal stabiliser has developed loose rivets, skin cracking and internal structural cracking during service.\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\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 focused on a specific airframe component. It has not expanded beyond its original purpose of mandating a stabiliser modification for identified aircraft."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 4 defined elements: applicability (aircraft models/serial numbers), reference document (SB NMD-55-10), compliance deadline, and brief background","No cross-references to other legislation or regulations beyond the enabling 'Civil Aviation Regulations 1998, Part 39'","Single unconditional requirement: comply with the service bulletin before the deadline","No exceptions, exemptions, or conditional logic","Standardised AD format with predictable structure"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific GAF aircraft models (the N22, N22B, N24 and N24A series) to carry out a **modification to the horizontal stabiliser** (the small wing at the tail of the plane that helps keep the aircraft level). The modification must follow the instructions in **Service Bulletin NMD-55-10** issued by the manufacturer (GAF).\n\n**Why it matters:** The horizontal stabiliser on these aircraft had been developing serious problems in service — **loose rivets, cracked skin, and internal structural cracking**. These defects could compromise the aircraft's structural integrity and flight safety. This directive makes the fix **legally mandatory** rather than optional.\n\n**Who must comply:** Anyone operating the affected aircraft models with serial numbers listed in the service bulletin. The work had to be completed **before 1 August 1980**.\n\n**Key point:** This is a **retrospective safety mandate**. Even though the aircraft were already in service, the regulator required this modification to address a discovered design or maintenance issue before further flight."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive's scope is limited to the specific GAF N22/N24 models with serial numbers referenced in the service bulletin and requires a one-off modification by a fixed date. The text contains no indication that this scope has been expanded or altered from its stated terms within the document."},"complexity_factors":["Narrow, model- and serial-number-based applicability reduces ambiguous scope (Applicability).","Single, fixed compliance action and deadline simplify compliance planning (Compliance).","Technical requirements are outsourced to an external document (GAF SB NMD-55-10), requiring cross-reference to that bulletin for details (Document).","No enforcement mechanisms, cost estimates or alternative compliance options are included in the AD itself, which leaves some practical uncertainties for operators (Compliance; Document).","Identification of affected aircraft requires access to and review of the service bulletin's serial number list (Applicability; Document)."],"plain_english_summary":"This airworthiness directive mandates a modification to the horizontal stabiliser on GAF N22/N22B/N24/N24A aeroplanes whose serial numbers are listed in GAF service bulletin NMD-55-10, to be completed by 1 August 1980. It responds to reported loose rivets, skin and internal cracking.  \n\nOwners/operators of the affected aircraft must locate their serial numbers, arrange and pay for the work and downtime; the AD delegates the technical method of compliance to the referenced service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-gaf-n22-36-horizontal-stabiliser-modification","history":"/api/acts/ad-gaf-n22-36-horizontal-stabiliser-modification/history","analysis":"/api/acts/ad-gaf-n22-36-horizontal-stabiliser-modification/analysis","conflicts":"/api/acts/ad-gaf-n22-36-horizontal-stabiliser-modification/conflicts","importantCases":"/api/acts/ad-gaf-n22-36-horizontal-stabiliser-modification/important-cases","documents":"/api/acts/ad-gaf-n22-36-horizontal-stabiliser-modification/documents"}}