{"id":"F2009L01189","name":"AD/S-92/6 - Main Gearbox Filter Bowl Assembly Mounting Studs","slug":"ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":122049,"registerId":"commonwealth-F2009L01189-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Sikorsky S-92 Series Helicopters","sectionType":"division","heading":"Sikorsky S-92 Series Helicopters","content":"### Sikorsky S-92 Series Helicopters\n\n| AD/S-92/6 | Main Gearbox Filter BowlAssembly Mounting Studs | 5/2009 TX |\n| --------- | ----------------------------------------------- | --------- |\n\n| Applicability: | Sikorsky Aircraft Corporation S-92A helicopters with a main gearbox assembly, part number (P/N) 92351-15110-042, -043, or -044, that is not marked with “TS-062-01” near the P/N.                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Remove the titanium studs by following the accomplishment instructions in Sikorsky Alert Service Bulletin (ASB) No. 92-63-014, Rev A dated20 March 2009 paragraph 3.A.2. Visually inspect the tapped holes and the main gearbox housing lockring counterbore for damage.Note 1: Figure 1 of the ASB contains guidance for removal and installation of the studs.3. Install steel studs and mark the main gearbox housing as “TS-062-01” near the P/N by following the accomplishment instructions of Sikorsky ASB No.92-63-014 Rev A paragraph 3.C.Note 2: FAA Emergency AD 2009-07-053 dated 23 March 2009 refers. |\n| Compliance:    | Before further flight after the effective date of this AD unless previously accomplished.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n|                | This Airworthiness Directive becomes effective on 27 March 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| Background:    | This AD is in response to the failure of 2 main gearbox filter bowl studs that were found broken during a fatal accident investigation in Canada. Prior to this accident the manufacture was investigation a July 2008 incident in Australia that also involved broken studs. In both cases the broken studs resulted in rapid loss of oil.This AD requires the replacement of titanium studs with steel studs.                                                                                                                                                                                                        |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n25 March 2009","sortOrder":0},{"sectionNumber":"AD/S-92/6","sectionType":"part","heading":"AD/S-92/6","content":"## AD/S-92/6","sortOrder":1},{"sectionNumber":"Main Gearbox Filter BowlAssembly Mountin","sectionType":"part","heading":"Main Gearbox Filter BowlAssembly Mounting Studs","content":"## Main Gearbox Filter Bowl  \nAssembly Mounting Studs","sortOrder":2},{"sectionNumber":"5/2009 TX","sectionType":"part","heading":"5/2009 TX","content":"## 5/2009 TX","sortOrder":3}],"analysis":{"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"},"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. The scope remains precisely limited to the identified defective component (titanium studs) in the specified helicopter series. No scope creep is evident."},"complexity_factors":["Single, specific technical requirement with clear part numbers and reference to external service bulletin","No conditional logic or nested exceptions — applies to all listed aircraft or none","Straightforward compliance deadline (before next flight)","Only 3 defined part numbers in applicability section","Single cross-reference to FAA Emergency AD for background context only"],"plain_english_summary":"This AD requires owners/operators of affected Sikorsky S‑92A helicopters to immediately replace titanium main‑gearbox mounting studs with steel ones, visually inspect the gearbox housing during replacement, and mark the gearbox \"TS‑062‑01\". It applies to helicopters with specified gearbox part numbers that haven’t been modified. Issued after stud failures caused a fatal crash and a serious incident, compliance is mandatory before the next flight to prevent catastrophic gearbox oil loss and failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive applies to a specific set of main gearbox assemblies and requires replacing titanium studs with steel studs, inspecting for damage, and marking the housing. This aligns with the stated original purpose (addressing stud failures and resultant oil loss) and does not expand scope beyond those assemblies or add unrelated obligations."},"complexity_factors":["Narrow applicability: only S-92 helicopters with specific main gearbox P/Ns not already marked “TS-062-01”","Specific technical task: removal of titanium studs and installation of steel studs (requires mechanical skill and appropriate tooling)","Mandatory inspections: visual inspection of tapped holes and gearbox housing lockring counterbore for damage","Procedural dependence: work must follow Sikorsky ASB No. 92-63-014 Rev A (para 3.A.2 and 3.C) and its Figure 1 guidance","Time-critical compliance: must be done before next flight after the AD’s effective date","Record/marking requirement: main gearbox housing must be marked “TS-062-01” after compliance","Cross-reference to FAA Emergency AD 2009-07-05 adds an international regulatory coordination element"],"plain_english_summary":"Requires operators of Sikorsky S‑92 helicopters with main gearbox assemblies P/N 92351-15110-042, -043 or -044 (unless marked “TS-062-01”) to remove titanium filter-bowl mounting studs, inspect the tapped holes and counterbore for damage, fit steel studs, and mark the housing “TS-062-01”. The work must be completed before the next flight, following Sikorsky service instructions. The regulator says this addresses stud failures that led to oil loss and a fatal accident; operators pay for parts and maintenance and must follow the specified service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs","history":"/api/acts/ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs/history","analysis":"/api/acts/ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs/analysis","conflicts":"/api/acts/ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs/conflicts","importantCases":"/api/acts/ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs/important-cases","documents":"/api/acts/ad-s-92-6-main-gearbox-filter-bowl-assembly-mounting-studs/documents"}}