{"id":"F2006B01923","name":"AD/A320/33 Amdt 2 - Trimmable Horizontal Stabiliser Lightning Strike Protection Improvement","slug":"ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41145,"registerId":"commonwealth-F2006B01923-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A320/33 Amdt 2 - Trimmable Horizontal Stabiliser Lightning Strike Protection Improvement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAirbus Industrie A319, A320 and A321 Series Aeroplanes\n\nAD/A320/33\n\nAmdt 2\n\n  \n\nTrimmable Horizontal Stabiliser Lightning Strike Protection Improvement\n\n  \n10/95\n\nApplicability: All Model A320-111, \\-211, \\-212, \\-231 and \\-232 aircraft Serial Numbers 002 to 008,\n\n010 to 014, 016 to 078, 080 to 104, 106 to 363, 365 to 384, 386 to 411, 413 to 433,\n\n435 to 457, 459 to 467 and 469 to 472 all inclusive.\n\nRequirement: 1. Aircraft without modifications 22621 and 23556 incorporated during manufacture\n\n\\- incorporate the modifications in accordance with Airbus Industrie Service Bulletins A320-27-1041 Revision 1 dated 4 August 1993 and A320-29-1058 Revision 1 dated 28 November 1994 respectively.\n\n    2. Aircraft with modification 23556 incorporated during manufacture - action in accordance with Airbus Industrie All Operator Telex A320/AOT 29-10 R2 dated 13 February 1995.\n\n    3. Aircraft with modification 23556 incorporated in accordance with Airbus Industrie Service Bulletin A320-29-1058 original issue dated 16 July 1993 - action in accordance with any one of the following Airbus Industrie All Operator Telexes A320/AOT 29-10 dated 15 June 1994, Revision 1 dated 23 September 1994 and Revision 2 dated 13 February 1995.\n\nNote: DGAC AD 93-123-046(B)R1 dated 10 May 1995.\n\nCompliance: 1. The original compliance was within 3500 hours’ time in service from 14 October 1993. The compliance for Amendment 1 was prior to 30 September 1995, this remains unchanged for Requirement 1.\n\n2 and 3. Within 500 hours’ time in service from 14 September 1995.\n\nBackground: An operator has reported pitting marks on an elevator actuator shaft and slight leakage from some hydraulic pipe fittings, following a lightning strike on the elevator. Compliance with this Directive minimises the possibility of loss of hydraulic circuits being caused by lightning strikes in the elevator region. Amendment 1 was issued to reflect revisions to the Requirement Documents.\n\nThis Amendment is issued following a revision to the DGAC Airworthiness Directive and identifies the aircraft directly affected, corrects an error in the revision status of the requirement documents and introduces an additional action designed to ensure that the correct cable clamps are used.","sortOrder":0}],"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":4,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: improving lightning strike protection on the trimmable horizontal stabiliser of specific Airbus aircraft. Amendment 2 makes technical corrections (fixing document revision errors, identifying directly affected aircraft, adding a cable clamp specification) without expanding beyond the original safety intent."},"complexity_factors":["Multiple conditional requirement paths based on manufacturing modification status (three separate requirement branches)","Extensive cross-referencing to external Airbus documents (Service Bulletins and All Operator Telexes with specific revision dates)","Detailed serial number applicability list with multiple ranges and exclusions","Nested compliance deadlines that reference previous amendment deadlines","Reference to foreign aviation authority directive (DGAC AD 93-123-046(B)R1) for context"],"plain_english_summary":"This mandatory safety order requires operators of specific early-production Airbus A319/A320/A321 airframes to upgrade lightning protection on the trimmable horizontal stabiliser to stop lightning-induced pitting and hydraulic leaks that could disable elevator controls. It applies to listed serial-numbered aircraft operated in Australia and enforces compliance per Airbus service instructions or telexes — a grounding-level mandate; the original compliance windows are historical."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"This amendment adjusted the original Directive in three concrete ways: (1) it explicitly identifies the affected aircraft by serial number (narrowing/clarifying applicability), (2) it corrects an error about which revision of the Airbus requirement documents applies (affecting which technical instructions operators must follow), and (3) it adds an additional action to ensure correct cable clamps are used (a discrete technical requirement). These changes refine and extend the original safety measure rather than changing its fundamental purpose (lightning‑strike protection for the stabiliser/elevator region). The scope change is therefore modest and technical: clarifications and one added installation/check requirement rather than a broad policy redirection."},"complexity_factors":["Detailed applicability: multiple specific serial number ranges enumerated (many discrete SNs rather than broad ranges).","Multiple conditional compliance paths: three separate Requirement tracks depending on factory modifications 22621 and 23556 (Requirement 1, 2, 3).","References to multiple external documents and revision states: Airbus Service Bulletins A320-27-1041 Rev 1 and A320-29-1058 Rev 1, plus several All Operator Telexes (A320/AOT 29-10 and Revs), and a DGAC AD note.","Different compliance timeframes tied to different effective dates: original 3500 flight‑hour window from 14 Oct 1993 for Requirement 1; 500 flight‑hour window from 14 Sep 1995 for Requirements 2 and 3 (Compliance).","Amendment content: corrects document revision status and adds an additional discrete action (cable clamp check), introducing a version control and scope-change element.","Dependency on operator records/history: must determine whether mods 22621/23556 were incorporated at manufacture or later, increasing pre‑work verification burden.","External normative material controls the technical method of compliance (SBs/AOTs) rather than the Directive containing full technical detail."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- It requires certain Airbus A319/A320/A321 aeroplanes (specific serial numbers listed) to have lightning-strike protection work done on the trimmable horizontal stabiliser and nearby elevator/hydraulic installations.\n- The required work is to incorporate specified Airbus modifications or to follow specified Airbus All Operator Telex (AOT) instructions. The references are Airbus Service Bulletins A320-27-1041 Rev 1 and A320-29-1058 Rev 1, and several AOTs (A320/AOT 29-10 and its revisions). (See Requirement 1, 2 and 3.)\n- The Directive sets different actions depending on whether the aircraft already had factory modifications 22621 or 23556 incorporated. (Requirement 1–3.)\n- It fixes an earlier error about which document revisions apply and adds a discrete extra action to make sure the correct cable clamps are used.\n\n**Who is affected**\n\n- Operators and owners of Airbus Model A320 series aeroplanes listed by serial number in the Applicability section (A320-111, -211, -212, -231 and -232, specific SN ranges). Only the aircraft whose serial numbers are enumerated are in scope.\n- Maintenance organisations that will carry out the modifications or AOT instructions.\n\n**Deadlines and timing**\n\n- Aircraft that need the main modification (Requirement 1) had an original compliance window of 3500 flight hours from 14 October 1993; Amendment 1 left that deadline unchanged (that is, that earlier compliance requirement still applies as written).\n- For the actions under Requirement 2 and Requirement 3 (related to modification 23556 and earlier SB issue), compliance must be done within 500 flight hours from 14 September 1995.\n\n**Why the rule exists (stated purpose) and what it achieves mechanically**\n\n- The stated reason: an operator reported lightning strike damage (pitting on an elevator actuator shaft and some hydraulic fitting leakage) after a lightning strike on the elevator. The Directive’s prescribed modifications and checks are intended to reduce the risk that a lightning strike in the elevator region will cause loss of hydraulic circuits. (Background.)\n\n**Who pays, who decides, and what behaviour changes**\n\n- Who pays: aircraft operators/owners bear the cost of carrying out the modifications, parts and associated maintenance labour and downtime.\n- Who decides: the Civil Aviation Safety Authority (CASA) requires compliance by issuing this Airworthiness Directive; Airbus documents (service bulletins and AOTs) specify the technical means of compliance and details of the work.\n- Behaviour changes: operators must schedule and perform the modifications or the AOT actions on affected aircraft within the specified time windows, and record compliance in maintenance logs. Maintenance organisations must follow the relevant SB/AOT instructions.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: parts, labour, aircraft out-of-service time, and administrative compliance. These are concentrated on affected aircraft owners/operators.\n- Benefits: reduced risk of hydraulic failure after lightning strikes in the stabiliser/elevator region. The safety benefit accrues to passengers, crew and the operator (diffuse benefit). The directive does not create a continuing fee or tax; it imposes a one-off (or periodic on‑condition) compliance cost per affected aircraft.\n- Implementation risks and opportunity costs: downtime and workshops capacity are required; if parts or certified maintenance capacity are limited, compliance could cause scheduling delays or higher cost. Operators must prioritise this mandated work over other maintenance items.\n\n**Compliance burden and practical issues**\n\n- The Directive relies on external Airbus technical documents and different versions of those documents — operators must ensure they apply the correct revision (the amendment corrects an earlier error about revision status).\n- There are three possible compliance paths depending on the aircraft’s existing configuration (no mods 22621/23556, mod 23556 incorporated at manufacture, mod 23556 incorporated by SB earlier). That conditional logic increases checks before work can start (Requirement 1–3).\n- The amendment also introduces an extra action to verify and use the correct cable clamps; that is a small additional parts/installation check but important for the lightning protection objective.\n\n**Effects on private enterprise and competition**\n\n- The requirement applies only to a defined set of aircraft; operators of those aircraft face additional short-term costs compared with operators of other models. This may disadvantage small operators who have fewer aircraft over which to spread the fixed compliance cost.\n- Maintenance providers will get work, which may concentrate business for those certified to do this Airbus work and supply the necessary parts.\n\n**Summary statement**\n\nMechanically, this Airworthiness Directive mandates lightning‑protection modifications and related checks on specified A320-series aircraft, provides different compliance paths depending on prior modifications, fixes which technical document revisions apply, and adds a clamp‑installation check. The stated safety aim is to reduce the chance a lightning strike will cause loss of hydraulic circuits in the elevator/stabiliser area. Operators must schedule and pay for the required work within the stated time windows and follow the Airbus SBs/AOTs as the means of compliance (Requirement 1–3; Compliance; Background)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement","history":"/api/acts/ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement/history","analysis":"/api/acts/ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement/analysis","conflicts":"/api/acts/ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement/conflicts","importantCases":"/api/acts/ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement/important-cases","documents":"/api/acts/ad-a320-33-amdt-2-trimmable-horizontal-stabiliser-lightning-strike-protection-improvement/documents"}}