{"id":"F2006B03460","name":"AD/BAe 146/108 - Aileron Servo and Trim Tab Drive Brackets","slug":"ad-bae-146-108-aileron-servo-and-trim-tab-drive-brackets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43014,"registerId":"commonwealth-F2006B03460-current","compilationNumber":null,"startDate":"2026-04-01","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\nBritish Aerospace BAe 146 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/BAe 146/108 Aileron Servo and Trim Ta","sectionType":"part","heading":"AD/BAe 146/108 Aileron Servo and Trim Tab Drive Brackets 1/2004","content":"# AD/BAe 146/108 Aileron Servo and Trim Tab Drive Brackets 1/2004\n\nApplicability: Model 146-RJ Series aircraft, with constructors numbers up to and including E3263. Requirement: Inspect in accordance with British Aerospace Mandatory Service Bulletin 57-48.\n\nNote: UK CAA AD 007-06-95 refers.\n\nCompliance: Unless already accomplished, before 22 February 2004.\n\nThis Airworthiness Directive becomes effective on 22 January 2004.\n\nBackground: The manufacturer received a report of corrosion on the bracket surface between the two tab drive flanges in the area of the two attachment bolts. This has resulted in cracking of the flanges at the base in severe corrosion cases.\n\nThis Directive is issued following a review of current UK CAA Airworthiness Directives applicable to 146-RJ aircraft.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 5 December 2003\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 24 December 2003.","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD stays within the original, narrow safety purpose: detect and correct corrosion/cracking on a specific bracket assembly of BAe 146-RJ aircraft. It does not expand regulatory scope beyond that targeted safety issue, nor does it add ongoing or system-wide obligations; it implements inspection and corrective action by reference to the manufacturer’s service bulletin."},"complexity_factors":["Short, single-issue directive with one required action (inspect per SB 57-48)","Limited applicability defined by model and constructor numbers (BAe 146-RJ up to E3263)","One fixed compliance deadline (22 February 2004)","Cross-reference to one manufacturer Mandatory Service Bulletin (technical content delegated)","Reference to related UK CAA AD but no multiple layered exceptions or alternative compliance paths"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- **Who it applies to:** Operators/owners of British Aerospace BAe 146-RJ series aeroplanes with constructor (serial) numbers up to and including E3263. (See: Applicability.)\n\n- **What it requires:** Those aircraft must be inspected in accordance with British Aerospace Mandatory Service Bulletin 57-48. (See: Requirement.)\n\n- **When it must be done by:** If the inspection has not already been completed, it must be done before 22 February 2004. (See: Compliance.)\n\n- **Why it was issued:** The manufacturer reported corrosion between the two tab drive flanges where the two attachment bolts fit; in severe cases the flange base can crack. The directive implements action intended to detect and address this unsafe condition. (See: Background.)\n\n- **References:** The AD notes the related UK CAA AD 007-06-95. The directive becomes effective 22 January 2004.\n\n\n**Plain-language explanation for a non-technical reader**\n\n- The regulator (Civil Aviation Safety Authority, via its delegate) is telling certain BAe 146-RJ aircraft operators to check specific brackets that control the aileron servo and trim tab drive for corrosion and cracking.\n- The inspection must follow the detailed steps laid out by the aircraft manufacturer in its Mandatory Service Bulletin 57-48. The bulletin will describe how to inspect, and what corrective action to take if corrosion or cracking is found.\n- If an operator has not already done the inspection, it must be completed by the stated deadline.\n\n\n**Who pays, who decides, and what changes**\n\n- The aircraft owner/operator pays for the inspection and any repairs or parts that are required by the inspection results.\n- The CASA delegate issues the requirement and the owner/operator must carry it out according to the manufacturer’s service bulletin.\n- Behaviourally, operators will schedule inspections (and possible repairs) for affected airframes ahead of the compliance date; maintenance organisations will follow the manufacturer’s technical instructions.\n\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: inspection labour, potential replacement brackets or repairs, and aircraft downtime while work is done. These are borne by aircraft owners/operators (Applicability / Compliance / Requirement).\n- Benefits are concentrated: the specific aircraft and their operators receive the safety benefit of finding and fixing corrosion before flange cracking leads to component failure. The safety benefit accrues to aircrew and passengers on those aircraft.\n- The requirement references the manufacturer’s service bulletin. That channels the technical solution to the OEM’s specified method, which both standardises the inspection and can concentrate aftermarket work (parts, repairs) with OEM-approved suppliers. That mechanism increases consistency but may restrict how independent maintenance providers perform or source repairs in practice.\n- Implementation risk: the AD relies on the manufacturer’s bulletin to set inspection technique and tolerances. If the bulletin is incomplete or if operators vary in how closely they follow it, inspections may be inconsistent. Tight compliance timing can also create scheduling pressure leading to short-term capacity constraints for maintenance providers.\n\n\n**Compliance burden and regulatory discretion**\n\n- Compliance is straightforward in scope (a single inspection action tied to a specific SB), but it creates an operational burden (bookings, possible component replacement).\n- The AD is issued under CASA regulation authority; the regulator decides the unsafe condition and required action, while the technical content is supplied by the manufacturer’s SB.\n\n\n**Potential unintended consequences/substitution effects**\n\n- Operators may accelerate inspections or retire affected aircraft if repair costs plus downtime are uneconomic for older airframes.\n- The referral to a manufacturer SB can concentrate demand for specific spare parts or repair kits to OEM channels.\n\n\n**Source citations (document sections):** Applicability; Requirement (British Aerospace Mandatory Service Bulletin 57-48); Compliance (deadline 22 February 2004); Background (report of corrosion and cracking); Note referencing UK CAA AD 007-06-95.\n\n\n**Analyst note on purpose-claims vs mechanics**\n\n- The stated purpose is to correct an unsafe condition (corrosion leading to flange cracking). Mechanically, the AD enforces detection (inspection) by mandating compliance with a manufacturer procedure and a compliance date. The trade-offs are the inspection and repair costs and aircraft downtime (borne by operators) versus reduced risk of component failure (borne by passengers, crew, and operators). The AD channels remedial action through the OEM service bulletin, which standardises technical action but may concentrate work and parts procurement through OEM channels (see Requirement and Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow-scope Airworthiness Directive addressing a specific safety defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspection for corrosion in aileron brackets."},"complexity_factors":["Very short document (approximately 250 words)","Only 3 defined structural sections: Applicability, Requirement, and Compliance","Single, unambiguous action required (inspect per specified service bulletin)","No nested exceptions or conditional logic — straightforward deadline-based compliance","Minimal cross-referencing (only one reference to UK CAA AD and one service bulletin)","No interpretation section with defined terms"],"plain_english_summary":"This AD requires owners/operators of BAe 146‑RJ aircraft (constructor numbers up to E3263) to carry out a visual inspection of the aileron servo and trim‑tab drive brackets due to discovered corrosion and cracking at the bracket flanges. Issued by CASA (adopting the UK action), the inspection follows the manufacturer’s mandatory service bulletin and is required to protect roll‑control integrity."},"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-bae-146-108-aileron-servo-and-trim-tab-drive-brackets","history":"/api/acts/ad-bae-146-108-aileron-servo-and-trim-tab-drive-brackets/history","analysis":"/api/acts/ad-bae-146-108-aileron-servo-and-trim-tab-drive-brackets/analysis","conflicts":"/api/acts/ad-bae-146-108-aileron-servo-and-trim-tab-drive-brackets/conflicts","importantCases":"/api/acts/ad-bae-146-108-aileron-servo-and-trim-tab-drive-brackets/important-cases","documents":"/api/acts/ad-bae-146-108-aileron-servo-and-trim-tab-drive-brackets/documents"}}