{"id":"F2019L01073","name":"AD/S-76/66 Amdt 1 Main Landing Gear Positioning Rod Assembly","slug":"ad-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":99693,"registerId":"commonwealth-F2019L01073-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Sikorsky Aircraft Corporation S-76 Serie","sectionType":"part","heading":"Sikorsky Aircraft Corporation S-76 Series Helicopters","content":"# Sikorsky Aircraft Corporation S-76 Series Helicopters\n\n| AD/S-76/66 Amdt 1 | Main Landing Gear Positioning Rod Assembly | 17/2019 |\n| ----------------- | ------------------------------------------ | ------- |\n\n| Applicability: | All Sikorsky S-76A, S-76B and S-76C model helicopters with the following parts installed:a. Positioning rod assembly Part Number (P/N) 1945E-31A or 2071-31, orb. Side brace rod end P/N 1945E-235 or 2071-235. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. a. Inspect the positioning rod assembly and side brace rod end for corrosion in accordance with Section 2, Accomplishment Instructions, in BFGoodrich Service Bulletin (SB) No. 76A-32-03, Revision 1, as in force on 15 September 2000.b. Replace any applicable part that is corroded with a serviceable part.2. a. If the positioning rod assembly or side brace rod end were inspected and re-assembled in accordance with BFGoodrich Component Maintenance Manual with Illustrated Parts List 1945/2071 Series Main Landing Gear, No. 32‑10‑01, as in force from time to time, within the period of 24 months before the commencement of this AD, inspect the positioning rod assembly and side brace rod end in accordance with Section 2 of SB 76A-32-03 Revision 1, as in force on 15 September 2000.b. Replace any applicable part that is corroded with a serviceable part.3. a. For side brace rod ends that are not re-assembled with Mastinox sealant or re-assembled with Mastinox sealant but without cadmium plate restoration; inspect the positioning rod assembly and side brace rod end for corrosion in accordance with Section 2 of SB 76A-32-03 Revision 1, as in force on 15 September 2000.b. Replace any applicable part that is corroded with a serviceable part.4. a. For side brace rod ends assembled with Mastinox sealant and cadmium plate restoration or for side brace rod ends re-assembled with Mastinox but that did not previously require rework due to corrosion, inspect the positioning rod assembly and side brace rod end for corrosion in accordance with Section 2 of SB 76A-32-03 Revision 1, as in force on 15 September 2000.b. Replace any applicable part that is corroded with a serviceable part.Note 1: Federal Aviation Administration of USA AD 2001-01-04 Amendment 39-12074 refers. |\n| | Note 2: The words “as in force from time to time” require compliance with the most recent version of the referenced document. |\n| Compliance: | 1. a. Unless previously accomplished, within 14 days after the commencement of this AD.b. Before further flight.2. a. Unless previously accomplished, within 42 days after the commencement of this AD.b. Before further flight.3. a. At intervals not to exceed 90 days.b. Before further flight.4. a. At intervals not to exceed 12 months or 1,500 hours’ time in service, whichever occurs first.b. Before further flight. |\n| | This AD commences on 23 August 2019. |\n| Background: | The FAA received a report of a landing gear collapse cause by corrosion due to dissimilar metals in the landing gear rod end. The actions specified by this Directive are intended to detect corrosion of the threaded joint in the rod assembly to prevent a collapse of the landing gear, and subsequent loss of control of the helicopter during landing.Amendment 1 of this AD is issued to expand the applicability of the AD by removing the aircraft serial number range, thereby making the AD applicable to all S‑76 helicopters that have the applicable part numbers for positioning rod assembly or side brace rod ends installed.This amendment action is considered necessary to address the possibility that the affected parts can be installed on all S-76 helicopters, including those models of later serial numbers. This possibility is confirmed by the effectivity of BFGoodrich Service Bulletin 76A-32-03, Revision 1, dated 15 September 2000 which includes all S-76A, S-76B and S-76C helicopters fitted with the affected parts. |\n\n![A drawing of a face\nDescription automatically generated](image.001.jpeg)\n\nPieter van Dijk \nDelegate of the Civil Aviation Safety Authority\n\n13 August 2019","sortOrder":0},{"sectionNumber":"AD/S-76/66 Amdt 1","sectionType":"part","heading":"AD/S-76/66 Amdt 1","content":"## AD/S-76/66 Amdt 1","sortOrder":1},{"sectionNumber":"Main Landing Gear Positioning Rod Assemb","sectionType":"part","heading":"Main Landing Gear Positioning Rod Assembly","content":"## Main Landing Gear Positioning Rod Assembly","sortOrder":2},{"sectionNumber":"17/2019","sectionType":"part","heading":"17/2019","content":"## 17/2019","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":true,"description":"This is Amendment 1 to an existing AD. The original AD was limited to specific aircraft serial numbers. This amendment expands applicability to ALL Sikorsky S-76A, S-76B, and S-76C helicopters that have the affected part numbers installed, regardless of serial number. The change was made because the affected parts could potentially be installed on any aircraft in the series, not just those originally identified."},"complexity_factors":["Four distinct compliance pathways with different inspection intervals based on maintenance history and assembly methods","Multiple cross-references to external technical documents (BFGoodrich Service Bulletin 76A-32-03 Revision 1, Component Maintenance Manual 32-10-01, and FAA AD 2001-01-04)","Conditional logic requiring operators to determine which of four scenarios applies to their aircraft","Dual compliance triggers for each requirement (calendar time AND 'before further flight' for failed inspections)","Technical aviation terminology requiring specialized knowledge (Mastinox sealant, cadmium plate restoration, time in service)","Version control complexity: documents referenced 'as in force on 15 September 2000' versus 'as in force from time to time'"],"plain_english_summary":"This AD requires owners/operators of Sikorsky S‑76A/B/C helicopters fitted with certain BFGoodrich main landing‑gear positioning rod assemblies or side‑brace rod ends to inspect for corrosion and replace any unserviceable parts. It responds to corrosion at dissimilar‑metal joints that has caused a gear collapse, and mandates recurring inspections with intervals that depend on prior maintenance and whether rod ends are properly sealed/restored. It expands the requirement fleetwide to prevent catastrophic landing‑gear failure."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Amendment 1 expanded the AD's applicability by removing an earlier serial‑number limitation and making the directive apply to all S‑76A, S‑76B and S‑76C helicopters that have the listed positioning rod assembly or side brace rod‑end part numbers installed. Concretely, the affected population increased from a serial‑number subset to any airframe where the specified P/Ns are fitted. This increases the number of operators required to comply and raises aggregate inspection and replacement workload; it also increases reliance on maintenance records to determine applicable inspection intervals."},"complexity_factors":["Multiple conditional inspection schedules (four distinct cases with different intervals: 14 days, 42 days, every 90 days, or every 12 months/1,500 hours)","Cross‑references to external technical documents (BFGoodrich SB 76A‑32‑03 Revision 1; BFGoodrich CMM 1945/2071 No. 32‑10‑01) with \"as in force from time to time\" wording","Applicability is by part number (4 part numbers) rather than by aircraft serial number, which changes population scope","Requirement text split into numbered subparts with eligibility based on prior re‑assembly history (requires checking maintenance records)","Reference to a foreign regulator's AD (FAA AD 2001‑01‑04) creates an external normative link","Replacement action required when corrosion found (binary outcome: serviceable vs corroded) but inspection procedures are externally defined (delegates procedural detail)","Note‑driven compliance interpretation obligations (operators must track latest service document versions)"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an airworthiness directive that requires inspection of the main landing gear \"positioning rod assembly\" and the associated \"side brace rod end\" on specified Sikorsky S‑76 helicopters, and replacement of any corroded parts found. (See Requirement paragraphs 1–4.)\n- It directs operators to follow the inspection steps in Section 2 of BFGoodrich Service Bulletin (SB) No. 76A‑32‑03 Revision 1 (dated 15 September 2000), and to comply with the most recent versions of the referenced maintenance documents where the AD says \"as in force from time to time.\" (Requirement 1.a; Note 2.)\n- Different inspection timing applies depending on how the rod ends were assembled or last serviced: short initial periods for some helicopters, recurring short-interval inspections for unprotected parts, and longer recurring intervals for parts assembled with both Mastinox sealant and cadmium plate restoration. (See Compliance timings in Requirements 1–4 and Compliance section.)\n\n**Who it affects**\n\n- Owners and operators of Sikorsky S‑76A, S‑76B and S‑76C helicopters that have either positioning rod assembly P/N 1945E‑31A or 2071‑31, or side brace rod end P/N 1945E‑235 or 2071‑235 installed. (Applicability.)\n- Maintenance organisations and technicians who perform inspections, re‑assembly and replacements under the BFGoodrich Component Maintenance Manual and the BFGoodrich Service Bulletin referenced by the AD. (Requirements 1–4.)\n\n**Why it matters (stated purpose and the safety mechanism)**\n\n- The AD responds to a reported landing‑gear collapse caused by corrosion at a threaded joint where dissimilar metals meet. The stated safety mechanism is to detect corrosion early in the threaded joint of the rod assembly and replace corroded parts before they cause landing‑gear failure and loss of control during landing. (Background.)\n\n**How compliance works in practice**\n\n- If your helicopter has the listed part numbers, you must inspect the parts per the SB instructions and replace any corroded component with a serviceable part. (Requirement 1.a–b.)\n- If the parts were re‑assembled under the BFGoodrich maintenance manual within 24 months before the AD started, a 42‑day inspection window applies unless already done. (Requirement 2 and Compliance 2.a.)\n- If the side brace rod end is not re‑assembled with Mastinox sealant (or re‑assembled with Mastinox but without cadmium plate restoration), inspections must be done every 90 days. (Requirement 3 and Compliance 3.a.)\n- If the side brace rod end was assembled with Mastinox and cadmium plate restoration (or re‑assembled with Mastinox and never required corrosion rework), inspections are required every 12 months or 1,500 flight hours, whichever comes first. (Requirement 4 and Compliance 4.a.)\n- The AD references the FAA AD and BFGoodrich service/maintenance documents; compliance therefore requires following those external documents as they stand (including their latest revisions when the AD refers to documents \"as in force from time to time\"). (Notes and Requirement references.)\n\n**Who pays, who decides, and what behaviour changes**\n\n- Operators (owners/lessees) pay for the inspections, parts removal/installation, and replacement parts and for the helicopter downtime while maintenance occurs. (Requirements; Compliance timing.)\n- Maintenance organisations and licensed technicians decide and carry out the inspections and any required rework or replacement, following the BFGoodrich SB and Component Maintenance Manual procedures specified. (Requirement references.)\n- The regulator (the Civil Aviation Safety Authority, via the AD) decides the mandatory compliance deadlines and references the service documents that define the inspection procedure. (AD issuance and Requirement references.)\n- Behavioural change required: operators must schedule inspections at the prescribed intervals, maintain records to show re‑assembly history (because that history determines inspection timing), and replace any corroded parts found.\n\n**Trade‑offs, costs, and implementation considerations**\n\n- Direct costs: inspection labour, replacement part costs, and aircraft downtime. These costs fall on operators and maintenance providers. (See Compliance intervals and replacement requirement language.)\n- Incentives: operators have an incentive to document re‑assembly and restoration work (Mastinox sealant and cadmium plating) because documented protection extends the interval between inspections (12 months/1,500 hours vs 90 days). (Requirements 3–4 and Compliance section.)\n- Supply/operational risk: replacing corroded parts requires availability of serviceable parts; widespread applicability could create demand pressure. (Applicability and Requirement 1.b.)\n- Compliance risk: the AD relies on maintenance records and on following external documents whose versions may change; operators must track the latest SB/CMM versions when the AD points to documents \"as in force from time to time.\" (Note 2.)\n- Effect on private choice and enterprise: the AD constrains maintenance scheduling and parts selection (operators may choose restoration practices that qualify for longer inspection intervals), but it does not prescribe who must perform maintenance beyond requiring adherence to the referenced maintenance documents.\n\n**Key references inside the AD**\n\n- BFGoodrich Service Bulletin No. 76A‑32‑03 Revision 1, Section 2 (inspection instructions).\n- BFGoodrich Component Maintenance Manual with Illustrated Parts List 1945/2071 Series Main Landing Gear, No. 32‑10‑01 (re‑assembly reference).\n- FAA AD 2001‑01‑04 (related foreign AD mentioned in Note 1).\n\n**Bottom line**\n\n- If your S‑76 has the listed positioning rod or side brace rod‑end part numbers, you must inspect them on the timetable specified in the AD and replace any corroded parts, with inspection frequency determined by the re‑assembly/protection history of the rod ends. The regulator expanded applicability so the requirements apply to all S‑76 helicopters with those parts installed."},"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-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly","history":"/api/acts/ad-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly/history","analysis":"/api/acts/ad-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly/analysis","conflicts":"/api/acts/ad-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly/conflicts","importantCases":"/api/acts/ad-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly/important-cases","documents":"/api/acts/ad-s-76-66-amdt-1-main-landing-gear-positioning-rod-assembly/documents"}}