{"id":"F2006B03524","name":"AD/BAe 146/77 Amdt 3 - Pylon to Wing Forward Attachment Bolts","slug":"ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43091,"registerId":"commonwealth-F2006B03524-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BAe 146/77 Amdt 3 - Pylon to Wing Forward Attachment Bolts","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BAe 146/77 Amdt 2 and issues the following AD under subregulation 39.1 (1) of CAR 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\nBritish Aerospace BAe 146 Series Aeroplanes\n\nAD/BAe 146/77\n\nAmdt 3\n\n  \nPylon to Wing Forward Attachment Bolts 11/2002\n\nApplicability: All BAe 146 series and Avro 146-RJ aircraft.\n\nNote: Check the Aircraft Technical Records for embodiment of modifications HCM01649A and HMC01649B before actioning the Requirement document.\n\nRequirement: Action in accordance with BAe Systems Mandatory Service Bulletin (SB) 54-010 Revision 1 or SB 54-010 Revision 2.\n\nCompliance: For aircraft that have achieved 4 years total time in service: Before accumulating 2,000 flights after 15 June 2000.\n\nFor aircraft that have not achieved 4 years total time in service:\n\nBefore accumulating 2,000 flights after 15 June 2000 or before achieving 4 years total time in service, whichever occurs later.\n\nThe compliance times remain unchanged by this issue. This Amendment becomes effective on 31 October 2002.\n\nBackground: The manufacturer received reports of in-service failures of engine pylon to wing forward attachment bolts. Investigation revealed the failures were due to corrosion in the bolt head undercut.\n\nAmendment 1 allowed the inspection procedure to be carried out with the engines installed.\n\nAmendment 2 introduced to the accomplishment instructions an alternative method to re-protect bolt non-threaded areas previously cadmium plated.\n\nAmendment 3 is issued to re- instate SB 54-010 Revision 1 as an equivalent Requirement document of this Directive.\n\nAmendment 2 of this Airworthiness Directive became effective on 16 May 2002.\n\nBritish Aerospace BAe 146 Series Aeroplanes\n\nAD/BAe 146/77 Amdt 3 (Continued)\n\nAmendment 1 of this Airworthiness Directive became effective on 15 June 2000.\n\nThe original issue of this Airworthiness Directive became effective on 30 December 1999.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 20 September 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 9 October 2002.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Amendment 3 does not broaden the set of affected aircraft or alter the compliance deadlines; it reinstates an earlier service bulletin revision as an acceptable method of compliance and revokes the prior amendment. The core safety scope—inspect and correct corrosion of pylon‑to‑wing forward attachment bolts on all BAe 146/Avro 146‑RJ aircraft—remains the same as the original AD. The change is procedural (which SB revision is accepted) rather than a substantive expansion of obligations or applicability."},"complexity_factors":["Short instrument but relies on external documents (BAe SB 54‑010 Revision 1 and Revision 2) for procedural detail","Conditional compliance logic tied to two variables (aircraft total time in service and number of flights) with a ‘whichever occurs later’ rule","Reference to aircraft technical records and two specific modifications (HCM01649A and HMC01649B) that may change applicability","Amendment history (original AD + Amdt 1 + Amdt 2 + Amdt 3) introduces multiple procedural variants (inspection with engines installed; alternative reprotection) to track","Cross‑reference to prior amendments and revocation language (Amdt 3 revokes Amdt 2 and reinstates Rev 1 equivalence), which requires reading both the AD and the SBs to confirm current acceptable methods"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Revokes the previous amendment (AD/BAe 146/77 Amdt 2) and issues Amendment 3 of Airworthiness Directive AD/BAe 146/77. (See opening paragraph and heading.)\n- Requires operators of BAe 146 series and Avro 146‑RJ aeroplanes to inspect and, where necessary, repair or protect the forward engine pylon‑to‑wing attachment bolts in accordance with the manufacturer’s mandatory Service Bulletin (SB 54‑010 Revision 1 or Revision 2). (Requirement)\n- Instructs operators to check the aircraft technical records first to see if modifications HCM01649A or HMC01649B have already been embodied; that may affect whether the SB action is needed. (Applicability/Note)\n- Sets specific compliance windows tied to aircraft age and flight cycles: \n  - For aircraft that had already reached 4 years total time in service as of 15 June 2000: do the SB action before accumulating 2,000 flights after 15 June 2000. (Compliance)\n  - For aircraft that had not yet reached 4 years total time in service as of 15 June 2000: do the SB action before accumulating 2,000 flights after 15 June 2000 or before reaching 4 years total time in service, whichever is later. (Compliance)\n\n**Why the action is required (stated reason)**\n\n- The manufacturer reported in‑service failures of the forward pylon‑to‑wing attachment bolts. Investigation found corrosion under the bolt head (in the undercut) caused these failures. The AD’s stated purpose is to correct that unsafe condition by mandating inspection and corrective action per the service bulletin. (Background)\n\n**What changed compared with earlier amendments**\n\n- Amendment 1 previously allowed the inspection procedure to be carried out with engines installed (reduces need for engine removal). (Background)\n- Amendment 2 had introduced an alternative method to re‑protect the non‑threaded areas of bolts that were previously cadmium plated. (Background)\n- Amendment 3 reinstates SB 54‑010 Revision 1 as an equivalent required document alongside Revision 2 (i.e. both revisions are acceptable means of compliance). It therefore revokes Amdt 2 and restores equivalence of the earlier SB revision. (Background/Requirement)\n\n**Who is affected and who pays**\n\n- Affected parties: operators and owners of BAe 146 series and Avro 146‑RJ aircraft (Applicability). Licensed maintenance organisations and technicians who perform the inspections and repairs are also operationally affected.\n- Who pays: aircraft operators pay for the inspection, any repairs or re‑protection work, replacement bolts if required, and associated downtime. Maintenance providers perform the work under commercial arrangements with the operator.\n\n**How it changes behaviour and decisions**\n\n- Operators must: (1) check records for specific mods (HCM01649A/HMC01649B); (2) arrange inspections and corrective actions per the specified SB revision; and (3) schedule those actions within the AD’s flight‑cycle/age deadlines. (Applicability/Requirement/Compliance)\n- Maintenance providers must follow the SB instructions (either Revision 1 or 2) when performing the mandated work.\n- The regulator (CASA delegate) decides which SB revisions are acceptable and may amend the AD to alter acceptable methods. (Opening paragraph/Background)\n\n**Practical trade‑offs, costs, and risks**\n\n- Direct costs: labour, inspection time, replacement parts, re‑protection materials, and aircraft downtime. These are borne by operators and vary with whether bolts require removal, replacement or re‑protection.\n- Opportunity costs: aircraft availability is reduced during inspection/repair; scheduling constraints can affect airline operations and revenue.\n- Implementation risk: effectiveness depends on correct application of the SB instructions, accurate technical‑record checks for the listed modifications, and availability of appropriately skilled maintenance personnel and parts.\n- Compliance burden: operators must interpret the age/flight‑cycle deadlines and ensure work is completed within those windows. The AD cross‑references manufacturer documentation (SB 54‑010 Rev 1 or Rev 2), so compliance requires access to and compliance with that external document.\n- Incentives and market effects: the AD creates immediate maintenance demand for operators and work for certified maintenance organisations. Where engine removal would otherwise be required, the allowance to inspect with engines installed (introduced earlier) can reduce cost and downtime, affecting operator choice between inspection methods.\n\n**Implementation discretion and monitoring**\n\n- The CASA delegate retains discretion to issue, revoke or amend ADs and to accept specified SB revisions as acceptable means of compliance (this amendment reinstates Rev 1 as equivalent). The AD does not itself set penalties but is a legal regulatory requirement under CAR 1998; operators are responsible for meeting the compliance schedule and following the SB.\n\n(References in parentheses indicate the part of the published AD from which the fact is drawn: Applicability, Requirement, Compliance, Background.)"},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"The legislation maintains its original narrow, technical scope: addressing a specific mechanical failure mode (corroded pylon bolts) on a specific aircraft type. Amendment 3 is purely procedural—restoring an alternative compliance document—without expanding the substantive requirements or affected aircraft population."},"complexity_factors":["Multiple amendment history (original plus 3 amendments) creates layered context","Dual compliance pathways based on aircraft age (4-year threshold)","Cross-reference to external technical document (BAe Systems Service Bulletin SB 54-010) without reproducing its contents","Specific flight-hour counting requirement (2,000 flights after fixed date)","Note regarding prior modifications (HCM01649A and HMC01649B) that affects applicability","Nested timing logic: 'whichever occurs later' for newer aircraft"],"plain_english_summary":"This CASA safety order requires all operators of BAe 146 and Avro 146‑RJ aircraft to carry out urgent inspections and repairs to engine‑pylon attachment bolts per BAe Systems Mandatory Service Bulletin SB 54‑010 (Revision 1 or 2). Corrosion in a groove under the bolt heads has led to in‑service failures and risk of engine separation. Amendment 3 restores Revision 1 as an acceptable alternative to Revision 2, giving operators compliant options within the specified flight/age deadlines."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts","history":"/api/acts/ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts/history","analysis":"/api/acts/ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts/analysis","conflicts":"/api/acts/ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts/conflicts","importantCases":"/api/acts/ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts/important-cases","documents":"/api/acts/ad-bae-146-77-amdt-3-pylon-to-wing-forward-attachment-bolts/documents"}}