{"id":"F2006B08872","name":"AD/DH 104/3 - Wing Root Main Spar Lower Joint - Modification","slug":"ad-dh-104-3-wing-root-main-spar-lower-joint-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52294,"registerId":"commonwealth-F2006B08872-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH 104/3 - Wing Root Main Spar Lower Joint - 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)  DH 104 (Dove) Series Aeroplanes\n\n \n\nAD/DH 104/3 Wing Root Main Spar Lower Joint - Modification 8/71\n\nApplicability: All models.\n\n \n\nDocument: 1. De Havilland Mod. No. Dove 686, Issue 2 (TNS CT(104) No. 100); or 2. ANO 105.1.14.13.5.6.\n\nCompliance: Before 1 September 1971.\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\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD as presented sets a single, clear scope: a mandatory modification for all DH 104 (Dove) models to be carried out according to the named technical document(s) by the stated deadline. The text contains no indication that the scope has been expanded or narrowed from a prior version; no amendment history or alternative applicability is included in the instrument itself."},"complexity_factors":["Broad applicability: applies to \"All models\" of the DH 104 series (clear but affects entire fleet).","Fixed, near-term compliance deadline: \"Before 1 September 1971\" requires scheduling and potential expedited work.","Reliance on external technical documents for the actual modification procedure (De Havilland Mod. No. Dove 686, Issue 2 or ANO 105.1.14.13.5.6) rather than including procedural detail in the AD text.","Short AD text with no stated exemptions, alternative methods of compliance, or enforcement/administrative process described within the instrument itself.","Practical compliance requires procurement of parts, labour and possible aircraft downtime—operational impacts not quantified in the AD."],"plain_english_summary":"What this instrument does, in plain terms:\n\n- It is an Airworthiness Directive (an instruction issued under the Civil Aviation Regulations, Part 39, by the Civil Aviation Safety Authority) that requires a specific modification to the DH 104 (Dove) series aeroplanes. (Header: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES\".)\n\n- The directive is titled \"AD/DH 104/3 Wing Root Main Spar Lower Joint - Modification\" and is dated 8/71.\n\n- Mechanically, the directive requires operators to carry out the modification described in one of two specified technical documents: either De Havilland Mod. No. Dove 686, Issue 2 (TNS CT(104) No. 100) or ANO 105.1.14.13.5.6. (Document: \"1. De Havilland Mod. No. Dove 686, Issue 2 (TNS CT(104) No. 100); or 2. ANO 105.1.14.13.5.6.\")\n\n- The directive applies to all models of the DH 104 (Dove) series. (Applicability: \"All models.\")\n\n- The required modification must be completed by the set deadline: before 1 September 1971. (Compliance: \"Before 1 September 1971.\")\n\nWho this affects and who pays:\n\n- The directive applies to every operator/owner of a DH 104 (Dove) aircraft because the applicability is \"All models.\" (Applicability: \"All models.\")\n\n- Practically, the operators or owners are the parties who must arrange and pay for the modification: they must obtain the referenced technical document(s), source any required parts or services, and schedule the work so it is done before the compliance date. (Document and Compliance entries.)\n\nHow it works mechanically and what choices are constrained:\n\n- The AD does not itself describe step‑by‑step modification actions in the body of the text; instead it points to external technical documents that contain the actual modification procedures. Operators must follow one of those documents to comply. (Document: \"De Havilland Mod. No. Dove 686, Issue 2 ... or ANO 105.1.14.13.5.6.\")\n\n- The directive sets a firm compliance deadline. That creates a time constraint that can require work to be prioritised, potentially imposing aircraft downtime and associated commercial costs.\n\nCosts, incentives and trade-offs (mechanisms, not judgements):\n\n- Direct costs: obtaining the technical documents, parts and materials specified in the referenced modification, and paying labour or contractor fees to perform the modification.\n\n- Indirect costs: aircraft out of service during modification, administrative time to schedule and document compliance, and possible inspection or certification actions after completion.\n\n- Incentives: operators have a clear legal obligation to comply by the deadline; non‑compliance would leave the operator with the risk of regulatory enforcement (the AD itself is the legal instrument imposing the duty). The AD does not set out a process for applying for relief or an alternative method of compliance in its text.\n\nImplementation and compliance considerations:\n\n- To implement the modification an operator needs access to the referenced technical document(s). The AD text does not include the technical content of the modification, so compliance depends on obtaining and following those documents. (Document: \"De Havilland Mod. No. Dove 686, Issue 2 ... or ANO 105.1.14.13.5.6.\")\n\n- The AD does not specify enforcement mechanics, exemptions, or who bears certification costs after modification; those operational details would be handled under the regulator's usual processes rather than in this short AD text.\n\nSummary sentence:\n\n- This AD mandates that all DH 104 (Dove) aircraft be modified at the wing root main spar lower joint in accordance with one of two specified technical documents, completed before 1 September 1971; the obligation and practical costs fall on aircraft owners/operators, who must obtain the referenced document and schedule the work to meet the deadline. (Applicability; Document; Compliance.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue Airworthiness Directive from 1971. It has not grown beyond its original purpose; it addresses one specific structural modification for one aircraft type. The scope remains precisely as intended: a targeted safety intervention for the DH 104 Dove wing spar issue."},"complexity_factors":["Single, specific technical requirement (one modification to one component)","Only 2 alternative compliance documents referenced","No defined terms section or interpretation provisions","Simple applicability clause ('All models')","Fixed date compliance with no conditional exceptions","Extremely short document (approximately 150 words of substantive content)","No cross-referencing to other legislation or regulatory parts beyond the enabling regulation citation"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for **De Havilland DH 104 Dove aircraft**.\n\n**What it does:**\n- Requires owners/operators to modify the **wing root main spar lower joint** — a critical structural component where the wing attaches to the fuselage.\n- The modification must be done according to specific technical documents: either De Havilland Modification No. Dove 686 (Issue 2) or an older UK Airworthiness Notice (ANO 105.1.14.13.5.6).\n\n**Who it affects:**\n- All operators of DH 104 Dove series aeroplanes in Australia.\n\n**Why it matters:**\n- This addresses a potential structural failure risk. The main spar carries flight loads; if the lower joint fails, the wing could separate from the aircraft. The directive was issued after 8/71 (August 1971) with a compliance deadline of **1 September 1971**, indicating urgency due to safety concerns.\n\n**Key takeaway:** This is a **mandatory, time-critical safety fix** for a specific vintage aircraft type, ensuring structural integrity of the wing attachment point."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh-104-3-wing-root-main-spar-lower-joint-modification","history":"/api/acts/ad-dh-104-3-wing-root-main-spar-lower-joint-modification/history","analysis":"/api/acts/ad-dh-104-3-wing-root-main-spar-lower-joint-modification/analysis","conflicts":"/api/acts/ad-dh-104-3-wing-root-main-spar-lower-joint-modification/conflicts","importantCases":"/api/acts/ad-dh-104-3-wing-root-main-spar-lower-joint-modification/important-cases","documents":"/api/acts/ad-dh-104-3-wing-root-main-spar-lower-joint-modification/documents"}}