{"id":"F2006B05349","name":"AD/P68/21 - Horizontal Stabilator to Fuselage Frame Attachment - Check Torque","slug":"ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":45862,"registerId":"commonwealth-F2006B05349-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/P68/21 - Horizontal Stabilator to Fuselage Frame Attachment - Check Torque","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)  Partenavia P68 Series Aeroplanes\n\n \n\nAD/P68/21 Horizontal Stabilator to Fuselage Frame\n\nAttachment - Check Torque\n\n\n4/83\n\n \n\nApplicability: All Partenavia P68, P68B, P68C, P68C-TC and P68 Observer aircraft with S/Nos. 1 to 289 except S/Nos. 234, 256, 259, 269 and 288.\n\n \n\nRequirement: Check torque AN4-6A bolts securing the horizontal stabilator torque tube brackets to fuselage frame. If necessary retorque to correct torque value 78-83 LB inches.\n\n \n\nNote: RAI AD 83-3 and Partenavia SB No. 57 refer.\n\n \n\nCompliance: Before further flight.\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, targeted safety directive addressing a specific mechanical issue with specific aircraft. It has not expanded beyond its original purpose of ensuring the structural integrity of the horizontal stabilator attachment."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined applicability criteria (aircraft model and serial number range with 5 exceptions)","Single mechanical requirement with clear numerical specification (78-83 LB inches)","No cross-references to other legislation sections","No conditional logic or nested exceptions beyond the serial number exclusions","Simple compliance deadline ('before further flight')","Straightforward mechanical task (check torque, retorque if necessary)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of certain Partenavia P68 series aeroplanes to **check the tightness (torque) of specific bolts** that attach the horizontal stabilator (the moveable part of the tail that controls the aircraft's pitch) to the fuselage frame.\n\n**Who it affects:**\n- All Partenavia P68, P68B, P68C, P68C-TC and P68 Observer aircraft\n- **Serial numbers 1 to 289**, **except** serial numbers 234, 256, 259, 269 and 288\n\n**What must be done:**\n- Check the torque on **AN4-6A bolts** securing the horizontal stabilator torque tube brackets to the fuselage frame\n- If the bolts are not tight enough, retighten them to **78-83 pound-inches**\n\n**When it must be done:**\n- **Before further flight** — meaning immediately, before the aircraft flies again\n\n**Why it matters:**\nLoose bolts in the tail section could cause the stabilator to malfunction or detach, potentially leading to loss of control of the aircraft. This is a critical safety issue requiring immediate action.\n\n**Background references:**\n- Refers to Italian aviation authority directive RAI AD 83-3 and Partenavia Service Bulletin No. 57"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument, as printed, sets a specific, limited obligation (inspect and, if necessary, retorque specified bolts on defined aircraft) and requires completion before further flight. There is no language in the text indicating an amendment or widening/narrowing of scope beyond that stated Applicability and Requirement; therefore there is no evidence in this text that the scope has changed from the directive’s stated purpose."},"complexity_factors":["Narrow technical scope: single, specific maintenance action (check/retorque AN4-6A bolts to 78–83 lb·in) (Requirement).","Limited applicability defined by aircraft models and serial-number range, with a small set of serial-number exceptions (Applicability).","Immediate compliance requirement—action must be completed before further flight—creates operational urgency (Compliance).","Reference to external documents (RAI AD 83-3 and Partenavia SB No. 57) which may add procedural detail not contained in the directive itself (Note).","Low regulatory discretion: prescriptive torque value specified, leaving only method-of-compliance choices to maintenance providers (Requirement)."],"plain_english_summary":"What this instrument does (mechanics):\n\n- It requires a one-time inspection and, if necessary, re-torquing of the AN4-6A bolts that secure the horizontal stabilator torque-tube brackets to the fuselage frame to a specific torque value of 78–83 lb·in. (Requirement).\n- The directive applies to Partenavia P68 series aeroplanes listed by model and serial number: all P68, P68B, P68C, P68C-TC and P68 Observer aircraft with S/Ns 1–289 except S/Ns 234, 256, 259, 269 and 288 (Applicability).\n- The inspection and any corrective torquing must be completed before the aircraft is next flown (Compliance).\n- The directive cross-refers to RAI AD 83-3 and Partenavia Service Bulletin No. 57 for related information (Note).\n\nWho it affects and who decides:\n\n- Aircraft owners and operators of the listed Partenavia P68 aircraft are the parties required to obtain the inspection and, if needed, the re-torque (Applicability; Requirement).\n- The person or organisation performing the work (typically maintenance personnel or an approved maintenance organisation) decides the method of carrying out the torque check and the torque tool used, subject to meeting the specified torque requirement (Requirement).\n\nWhy it matters (official claim and practical consequences):\n\n- The directive’s immediate practical effect is to ensure the AN4-6A bolts are at the specified torque (Requirement). The instrument itself does not state a causal history beyond the instruction; it refers users to related documents for background (Note).\n- In practical terms this creates a short-term operational constraint: the affected aircraft cannot be flown until the check (and any retorque) is completed (Compliance). That generates direct costs for owners/operators in the form of labour, any replacement parts if found necessary, and aircraft downtime (Applicability; Requirement; Compliance).\n\nCosts, incentives and trade-offs (source-grounded):\n\n- Who pays: owners/operators bear the cost of inspection, labour and any corrective work because the applicability clause binds those aircraft (Applicability; Requirement).\n- Incentives: operators have a strong and immediate incentive to perform the check promptly because the aircraft must not be flown until compliance is achieved (Compliance). Completing the task restores legal ability to fly the aircraft.\n- Trade-offs and opportunity costs: time spent to perform the check and any corrective maintenance displaces other uses of the aircraft and labour capacity; those opportunity costs fall on the operator and their maintenance provider (Applicability; Requirement; Compliance).\n- Compliance burden: the action is narrowly defined (check and, if required, retorque to 78–83 lb·in) so procedural compliance is straightforward in technical terms, but it is mandatory and immediate (Requirement; Compliance).\n\nImplementation risk and discretion:\n\n- The directive prescribes the parameter to be achieved (78–83 lb·in) and the bolt type to be inspected (AN4-6A), leaving little regulatory discretion about what must be done; discretion mainly rests with the maintenance provider over means of compliance (Requirement).\n- The text references external documents (RAI AD 83-3 and Partenavia SB No. 57) which may contain additional procedural detail; locating and following those documents could affect the complexity of implementation (Note).\n\nNet effect on private choice and markets:\n\n- The directive imposes a mandatory technical check on a defined set of private aircraft (Applicability; Requirement). Operators must choose when and how to schedule the inspection with available maintenance providers, and will incur the direct cost and downtime consequences of that choice (Requirement; Compliance).\n\nSource citations: the summary statements above are drawn from the instrument’s Applicability, Requirement, Compliance and Note sections as printed in the directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque","history":"/api/acts/ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque/history","analysis":"/api/acts/ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque/analysis","conflicts":"/api/acts/ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque/conflicts","importantCases":"/api/acts/ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque/important-cases","documents":"/api/acts/ad-p68-21-horizontal-stabilator-to-fuselage-frame-attachment-check-torque/documents"}}