{"id":"F2007L00748","name":"AD/HU 369/116 - Lateral Mixer Output Link Assembly","slug":"ad-hu-369-116-lateral-mixer-output-link-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":64429,"registerId":"commonwealth-F2007L00748-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"McDonnell Douglas (Hughes) and Kawasaki ","sectionType":"division","heading":"McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters","content":"### McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters\n\n| AD/HU 369/116 | Lateral Mixer Output Link Assembly | 4/2007 |\n| ------------- | ---------------------------------- | ------ |\n\n| Applicability: | Model MD600N helicopters, with a lateral mixer output link assembly part number 600N7636-1, -3, -9 or -11, installed.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Remove each lateral mixer output link assembly (mixer link) and visually inspect, with a bright light and a 10x or higher magnifying glass, for cracks in the shaded areas around the bearing bore as depicted in the following Figure 1:Figure 12. Perform an eddy current inspection of each mixer link in the bearing end areas.Replace any cracked mixer link with a serviceable mixer link on which an eddy current inspection has been performed.Perform an eddy current inspection on each mixer link before installation on any helicopter.Note: FAA Emergency AD 2007-05-51 and MDHI Service Bulletin No. SB600N-044 refer. |\n| Compliance:    | Before further flight.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n|                | This Airworthiness Directive becomes effective on 12 April 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n\n| Background: | The FAA received a report of a cracked lateral mixer output link assembly part number 600N7636-1, on an in-service MDHI Model MD600N helicopter. Cracks were also detected on two additional mixer links part number 600N7636-3, which were being held as spares. The cracks on all three mixer links run through the bearing end area of the mixer link and emanate from staking marks in the mixer link. Undetected cracks in the mixer link could result in failure of the mixer link and subsequent loss of control of the helicopter. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n\n![](image.002.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n28 February 2007","sortOrder":0},{"sectionNumber":"AD/HU 369/116","sectionType":"part","heading":"AD/HU 369/116","content":"## AD/HU 369/116","sortOrder":1},{"sectionNumber":"Lateral Mixer Output Link Assembly","sectionType":"part","heading":"Lateral Mixer Output Link Assembly","content":"## Lateral Mixer Output Link Assembly","sortOrder":2},{"sectionNumber":"4/2007","sectionType":"part","heading":"4/2007","content":"## 4/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Scope is narrowly targeted to MD600N helicopters with the listed mixer link part numbers and to the specific inspection and replacement measures described. The instrument does not broaden applicability beyond those models/parts or add discretionary measures; it responds directly to reported cracks and mandates testing and replacement (Applicability; Requirement)."},"complexity_factors":["Technical inspection standard: mandates both close visual inspection (bright light, 10x magnification) and eddy‑current NDT of bearing ends — requires NDT capability or contracted service (Requirement).","Immediate compliance window: actions must be completed 'Before further flight', creating potential operational grounding and urgent logistical costs (Compliance).","Narrow, parts‑specific scope: applies only to MD600N helicopters with lateral mixer output link assembly P/N 600N7636-1, -3, -9 or -11 — limits applicability but concentrates impact on affected operators (Applicability).","Replacement obligation and spare control: cracked links must be replaced with serviceable parts that have had eddy‑current inspections; operators bear cost of replacement, spare testing and inventory management (Requirement).","Traceability and pre‑installation testing: eddy‑current inspection required before installation on any helicopter increases documentation and quality‑assurance burden on maintainers (Requirement).","Limited regulatory discretion: directive sets a specific effective date and a clear mandatory procedure with little administrative flexibility (Compliance; AD effective date)."],"plain_english_summary":"This directive requires operators of MD600N helicopters fitted with lateral mixer output link assemblies P/N 600N7636-1, -3, -9 or -11 to remove each mixer link and inspect it visually (bright light, 10x magnification) and by eddy‑current testing of the bearing ends, replacing any cracked part. Inspections (and eddy‑current testing before any installation) must be done before further flight because undetected cracks can lead to link failure and loss of helicopter control."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical failure mode in a specific helicopter model. The scope remains precisely limited to the lateral mixer output link assembly issue as originally identified."},"complexity_factors":["Very short document (approximately 300 words)","Only 4 specific part numbers in scope","Single mechanical component addressed","Clear, sequential compliance steps (remove, inspect visually, eddy current test, replace if needed)","No nested exceptions or conditional logic","Only one cross-reference (to FAA Emergency AD and manufacturer Service Bulletin)","Immediate compliance requirement with no alternative methods or phased implementation"],"plain_english_summary":"Owners/operators of MD600N helicopters must immediately remove and inspect the lateral mixer output link assembly (P/Ns ending -1, -3, -9, -11) before next flight. Visual inspection with magnification and a required eddy‑current check of the bearing ends are mandated; any cracked or untested parts must be replaced with eddy‑current‑verified units.\n\nThis urgent AD responds to cracking from staking marks that could lead to in‑flight loss of control."},"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-hu-369-116-lateral-mixer-output-link-assembly","history":"/api/acts/ad-hu-369-116-lateral-mixer-output-link-assembly/history","analysis":"/api/acts/ad-hu-369-116-lateral-mixer-output-link-assembly/analysis","conflicts":"/api/acts/ad-hu-369-116-lateral-mixer-output-link-assembly/conflicts","importantCases":"/api/acts/ad-hu-369-116-lateral-mixer-output-link-assembly/important-cases","documents":"/api/acts/ad-hu-369-116-lateral-mixer-output-link-assembly/documents"}}