{"id":"F2006B06748","name":"AD/S-76/72 - Main Landing Gear Brake Discs - Replacement","slug":"ad-s-76-72-main-landing-gear-brake-discs-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114575,"registerId":"commonwealth-F2006B06748-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nSikorsky S-76 Series Helicopters","sortOrder":0},{"sectionNumber":"AD/S-76/72 Main Landing Gear Brake Discs","sectionType":"part","heading":"AD/S-76/72 Main Landing Gear Brake Discs - Replacement 10/2003","content":"# AD/S-76/72 Main Landing Gear Brake Discs \\- Replacement 10/2003\n\nDM\n\nApplicability: Model S-76A, B and C series helicopters, with main landing gear brake (MLG) assembly part number (P/N) 5007555, 5007555-1, or 5007555-2 installed.\n\nRequirement: 1. Determine if a MLG brake disc P/N 5014067 is installed in the braking assembly in accordance with:\n\n    (a) For brake assembly P/N 5007555 and P/N 5007555-1:\n\nSection 111-Acommplishment Instructions, paragraph 1.A. to 1.D., of Aircraft Braking Systems Corporation Alert Service Bulletin (ASB) S76-32-A24, dated 10 April 2002; and\n\n    (b) For brake assembly P/N 5007555-2:\n\nSection 111-Acommplishment Instructions, paragraph 1.A. and 1.B., of Aircraft Braking Systems Corporation ASB S76-32-A25, dated 15 May 2002.\n\n    2. If it is determined, in compliance with Requirement 1, that a disc P/N 5014067 is installed, remove that disc and replace with disc P/N 5007672 and re-identify brake assembly:\n\n(a) P/N 5007555 and P/N 5007555-1 as brake assembly P/N 5007555-3, in accordance with the conversion of brake assembly instructions on page 6 of ASB S76-32-A24, dated 10 April 2002; and\n\n(b) P/N 5007555-2 as brake assembly P/N 5007555-4, in accordance with the conversion of brake assembly instructions on page 6 of ASB S76-32-A25, dated 15 May 2002.\n\n    3. Increase the Category A - Rejected Takeoff Distance, the Category A-Landing Distance, and the Category B - Landing Distance, as stated in the current Rotorcraft Flight Manual (RFM) for the helicopter, by multiplying these rejected takeoff and landing distances by a factor of 1.67. This can be accomplished by inserting into the helicopter flight manual a copy of this Directive, or the helicopter manufacturers temporary revision to the RFM reflecting increased rejected takeoff and landing distances.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific unsafe condition in specific helicopter models. It has not expanded beyond its original purpose of correcting a known brake disc defect."},"complexity_factors":["Multiple part number variants requiring different technical references (three brake assembly P/Ns mapped to two different service bulletins with different inspection paragraphs)","Cross-references to external manufacturer documents (ASB S76-32-A24 and ASB S76-32-A25) that are not reproduced in the directive itself","Conditional logic: Requirement 2 only triggers if Requirement 1 determines the unsafe disc is present","Specific page references to external documents (\"page 6\" of service bulletins)","Mathematical adjustment requirement (1.67 multiplier) with alternative compliance methods (insert copy of directive OR manufacturer's temporary revision)","Technical aviation terminology throughout (Category A/B operations, RFM, MLG, P/N, ASB)"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of certain Sikorsky S‑76A/B/C helicopters with specified brake assemblies to inspect for an unsafe brake disc (P/N 5014067) and, if found, replace it with the approved disc (P/N 5007672) and re‑label the assembly. \n\nUntil replacement, pilots must increase all takeoff and landing distance calculations by 67% and record the change. It prevents brake failure that could cause runway overruns."},"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"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The directive, as drafted, focuses solely on correcting an identified brake disc issue on S‑76A/B/C helicopters with the listed MLG assemblies by replacing a specific disc and updating flight manual distances (Applicability; Requirements 1–3). It does not broaden obligations to other models, unrelated components, or extend beyond the described corrective actions; no expansion of scope beyond the stated remedial purpose is apparent in the provided text."},"complexity_factors":["Applicability is narrow but part‑number specific: applies only to S‑76A/B/C with MLG assembly P/N 5007555, 5007555-1 or 5007555-2 (Applicability).","Mandatory reliance on external manufacturer service documents: inspection and conversion steps must follow specific paragraphs of ASB S76-32-A24 and ASB S76-32-A25 (Requirement 1(a),(b); Requirement 2(a),(b)).","Parts replacement plus re‑identification: replacing disc P/N 5014067 with P/N 5007672 and changing assembly P/N to 5007555-3 or 5007555-4 adds parts procurement, logbook and inventory control burden (Requirement 2(a),(b)).","Operational performance change: multiplying rejected takeoff and landing distances by 1.67 requires RFM amendment, crew retraining/briefing and operational planning adjustments (Requirement 3).","Ambiguity about timing in supplied text: the AD states actions are required “at the time mentioned in the compliance section,” but the compliance timeframe is not included here, creating interpretive and scheduling uncertainty (Introductory paragraph).","Multiple actor responsibilities: the operator must implement inspections, maintenance organisations must perform replacements per ASB instructions, and documentation updates must be inserted into the RFM (Requirements 1–3)."],"plain_english_summary":"This airworthiness directive orders operators of Sikorsky S‑76A/B/C helicopters with specified main landing gear brake assemblies to check for brake disc P/N 5014067 and, if found, replace it with P/N 5007672 and re‑identify the assembly. It also requires increasing rejected takeoff and landing distances in the Rotorcraft Flight Manual by multiplying those distances by 1.67. The actions must follow the referenced Aircraft Braking Systems Alert Service Bulletins and be carried out by operators and maintenance organisations."}},"importantCases":[],"_links":{"self":"/api/acts/ad-s-76-72-main-landing-gear-brake-discs-replacement","history":"/api/acts/ad-s-76-72-main-landing-gear-brake-discs-replacement/history","analysis":"/api/acts/ad-s-76-72-main-landing-gear-brake-discs-replacement/analysis","conflicts":"/api/acts/ad-s-76-72-main-landing-gear-brake-discs-replacement/conflicts","importantCases":"/api/acts/ad-s-76-72-main-landing-gear-brake-discs-replacement/important-cases","documents":"/api/acts/ad-s-76-72-main-landing-gear-brake-discs-replacement/documents"}}