{"id":"F2007L00311","name":"AD/MU-2/71 - Wing Attachment Barrel Nuts and Bolts","slug":"ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68692,"registerId":"commonwealth-F2007L00311-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Mitsubishi MU-2 Series Aeroplanes","sectionType":"division","heading":"Mitsubishi MU-2 Series Aeroplanes","content":"### Mitsubishi MU-2 Series Aeroplanes\n\n| AD/MU-2/71 | Wing Attachment Barrel Nuts and Bolts | 3/2007 |\n| ---------- | ------------------------------------- | ------ |\n\n| Applicability: | Model MU-2B-10, -15, -20, -25, -26 aircraft, serial numbers 101 through 347, except serial numbers 313 and 321.Model MU-2B-30, -35, -36 aircraft, serial numbers 501 through 696, except serial numbers 652 and 661.                                                                                                                |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Mitsubishi Service Bulletin No. 241A dated21 November 2006 or later JCAB approved revisions.Note: JCAB AD TCD-7030-2006 refers.                                                                                                                                                                           |\n| Compliance:    | Within 200 hours time in service or 12 months after 15 March 2007, whichever occurs first.                                                                                                                                                                                                                                          |\n|                | This Airworthiness Directive becomes effective on 15 March 2007.                                                                                                                                                                                                                                                                    |\n| Background:    | The manufacturer received a report of several fractured wing attachment barrel nuts that were detected during routine maintenance. During a subsequent field survey, no additional cracked barrel nuts were detected, but a significant number of aircraft were found to have incorrect torque values on the wing attachment bolts. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n1 February 2007","sortOrder":0},{"sectionNumber":"AD/MU-2/71","sectionType":"part","heading":"AD/MU-2/71","content":"## AD/MU-2/71","sortOrder":1},{"sectionNumber":"Wing Attachment Barrel Nuts and Bolts","sectionType":"part","heading":"Wing Attachment Barrel Nuts and Bolts","content":"## Wing Attachment Barrel Nuts and Bolts","sortOrder":2},{"sectionNumber":"3/2007","sectionType":"part","heading":"3/2007","content":"## 3/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope is limited to the specified MU-2 models and serial-number ranges to address reported fractured barrel nuts and incorrect torque values. The instrument itself does not expand or narrow that stated applicability beyond the listed models/serials."},"complexity_factors":["Narrow technical focus (wing attachment barrel nuts and bolts) reduces legal ambiguity but requires specialised maintenance skills.","Limited applicability by specific MU-2 models and serial-number ranges increases administrative work for operators to confirm applicability.","Mandates compliance with an external document (Mitsubishi Service Bulletin No. 241A) and any later JCAB-approved revisions, creating dependency on manufacturer/regulator publications.","Definite compliance window (200 flight hours or 12 months from 15 March 2007) requires operational scheduling and possible aircraft downtime.","Potential for parts replacement and torque rework creates direct maintenance cost and logistical coordination for owners/operators.","Enforcement delegated to CASA (document signed by a CASA delegate) centralises the compliance decision and oversight."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Mitsubishi MU-2 aircraft to inspect the wing attachment barrel nuts and bolts, correct torque values, and carry out any repairs in accordance with Mitsubishi Service Bulletin No. 241A (or later JCAB-approved revisions). It was issued after reports of fractured barrel nuts and discovery of incorrect bolt torque. Owners and operators of the listed MU-2 models/serial ranges must comply within the stated flight-hours or months; CASA enforces the requirement."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard single-issue Airworthiness Directive addressing a specific safety defect in a specific aircraft type. The scope remains tightly focused on the original safety concern (wing attachment hardware integrity) with no evidence of scope creep or expansion beyond the initial safety finding."},"complexity_factors":["Very short document (under 300 words)","Only 4 defined applicability criteria (specific model variants and serial numbers)","Single compliance requirement referencing an external technical document","Simple time-based compliance trigger (hours OR calendar date, whichever first)","No nested exceptions, conditional logic, or cross-references to other legislation","Straightforward factual background with single causal chain"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Mitsubishi MU-2B aeroplanes (certain serial ranges) to inspect and repair wing attachment barrel nuts and bolts per Mitsubishi Service Bulletin No. 241A (Nov 2006). Work must be done within 200 flight hours or 12 months after 15 March 2007. It responds to fractured nuts and improperly tightened bolts that risk in‑flight structural failure; compliance is mandatory and required for legal flight."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts","history":"/api/acts/ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts/history","analysis":"/api/acts/ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts/analysis","conflicts":"/api/acts/ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts/conflicts","importantCases":"/api/acts/ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts/important-cases","documents":"/api/acts/ad-mu-2-71-wing-attachment-barrel-nuts-and-bolts/documents"}}