{"id":"F2008L03575","name":"AD/BAe 146/134 - Horizontal Stabiliser Lower Skin & Joint Plates","slug":"ad-bae-146-134-horizontal-stabiliser-lower-skin-joint-plates","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":75192,"registerId":"commonwealth-F2008L03575-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"British Aerospace BAe 146 Series Aeropla","sectionType":"division","heading":"British Aerospace BAe 146 Series Aeroplanes","content":"### British Aerospace BAe 146 Series Aeroplanes\n\n| AD/BAe 146/134 | Horizontal Stabiliser LowerSkin & Joint Plates | 11/2008 |\n| -------------- | ---------------------------------------------- | ------- |\n\n| Applicability: | BAe 146 Series 100 and 200 aircraft, serial numbers as identified in BAE Systems (Operations) Limited Inspection Service Bulletin ISB.55-020. |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Inspect the horizontal stabiliser lower skin and joint plates in accordance with paragraphs 2.C.(1) through 2.C.(3) of BAE Systems ISB.55-020 Initial issue, dated 11 December 2007 or later approved revision.If no damage is found, drill and ream four (4) holes in accordance with paragraph 2.C.(4)(a) and inspect the holes in accordance with paragraph 2.C.(4)(b).a. If distortion or corrosion is found in the rivet holes, before further flight, contact BAE Systems for approved repair instructions to be accomplished prior to fitting of the rivets.b. If no distortion or corrosion is found, before further flight, install the four rivets in accordance with paragraph 2.C.(4)(c) of ISB.55-020.2. Repeat the inspection in accordance with paragraphs 2.C.(1) through 2.C.(3).If damage is found during any inspection, before further flight, contact BAe Systems in accordance with paragraph 2.C.(5) of ISB.55.020 and accomplish an approved repair in accordance with paragraph 2.C.(6).Accomplishment of the approved repair in accordance with BAE Systems Repair Information Leaflet HC551H9061 (at issue 2, dated 16 November 2007 or later revision) on the left and right sides of the horizontal stabiliser is terminating action for the repetitive inspection requirement (2) of this AD.Note: EASA AD 2008-0167, dated 2 September 2008, refers. |\n| Compliance: | 1. No later than 6 months after 16 September 2008.2. At intervals not exceeding 24 months. |\n| | This Airworthiness Directive becomes effective on 23 October 2008. |\n\n| Background: | BAE Systems has determined that in order to assure the continued structural integrity of the horizontal stabiliser lower skin and joint plates in the rib 1 area of certainBAe 146 aircraft, a revised inspection programme for this area is considered necessary. The disbonding of joints can lead to corrosion which, if undetected, could result in degradation of the structural integrity of the horizontal stabiliser.Consequently, this AD requires the implementation of repetitive inspections and corrective actions, depending on inspection findings. It also provides an approved repair as optional terminating action for the repetitive inspections. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n8 September 2008","sortOrder":0},{"sectionNumber":"AD/BAe 146/134","sectionType":"part","heading":"AD/BAe 146/134","content":"## AD/BAe 146/134","sortOrder":1},{"sectionNumber":"Horizontal Stabiliser LowerSkin & Joint ","sectionType":"part","heading":"Horizontal Stabiliser LowerSkin & Joint Plates","content":"## Horizontal Stabiliser Lower \nSkin & Joint Plates","sortOrder":2},{"sectionNumber":"11/2008","sectionType":"part","heading":"11/2008","content":"## 11/2008","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD implements a revised inspection programme for the horizontal stabiliser lower skin and joint plates on the specified BAe 146 Series 100/200 aircraft and provides an approved repair as terminating action. It does not expand applicability beyond the identified serial numbers nor add new regulatory powers; it prescribes inspection, conditional repair pathways and compliance timing as set out in the instrument (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Cross-references to external manufacturer documents (BAE Systems ISB.55-020 and RIL HC551H9061) that operators must obtain and follow (Requirement).","Conditional, multi-step workflow: initial inspection steps, drilling/reaming of four holes if undamaged, inspection of holes, then either rivetting or contacting BAE for approved repair if distortion/corrosion is found (Requirement).","Repetitive inspection schedule with a specific initial deadline and recurring 24‑month interval (Compliance).","Applicability limited to certain serial-numbered BAe 146 Series 100/200 aircraft as identified in the ISB, requiring cross-checking serial records (Applicability).","Option of an approved repair as terminating action introduces an alternative compliance path that depends on availability and implementation of the RIL (Requirement; Background).","Operational and maintenance workload: drilling, reaming and rivetting/repairs require certified maintenance resources and create direct costs for operators (Requirement; Compliance).","Requirement to contact BAE for approved repair instructions where damage is found concentrates decision authority with the manufacturer for repair methodology (Requirement)."],"plain_english_summary":"Mandates repetitive inspections of the horizontal stabiliser lower skin and joint plates on specified BAe 146 Series 100 and 200 aircraft, requiring drilling/reaming, inspection and either installation of four rivets or a BAE‑approved repair per BAE Systems ISB.55‑020; completing Repair Information Leaflet HC551H9061 on both sides terminates the repeats. \n\nAircraft operators must arrange and pay for the inspections and any repairs, comply within six months and then every 24 months, and follow BAE’s approved instructions; CASA enforces the AD because disbonding can cause corrosion and structural degradation. (Requirement; Compliance; Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific structural integrity issue identified by the manufacturer. The scope remains precisely limited to the horizontal stabiliser inspection and repair requirements for the specified aircraft models. There is no evidence of scope creep or expansion beyond the original safety purpose."},"complexity_factors":["Single, specific technical subject matter (horizontal stabiliser inspection)","Clear, linear compliance structure with only two deadlines (initial and recurring)","References to external technical documents (BAE Systems service bulletin and repair leaflet) rather than embedding all technical detail","Simple conditional logic: if damage found → repair; if no damage → install rivets; optional terminating action available","Limited applicability (specific aircraft series and serial numbers)","No nested definitions, interpretation sections, or extensive cross-referencing within the instrument itself"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of certain BAe 146 Series 100 and 200 aircraft to inspect the horizontal stabiliser lower skin and joint plates near rib 1 because BAE found disbonding that can lead to corrosion and weakened tail structure. \n\nIt mandates initial and recurring inspections, grounding for flights if damage is found until manufacturer-approved repairs are made, and offers an optional terminating repair to stop repetitive checks — affecting the limited fleet listed in the manufacturer’s service bulletin."},"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-146-134-horizontal-stabiliser-lower-skin-joint-plates","history":"/api/acts/ad-bae-146-134-horizontal-stabiliser-lower-skin-joint-plates/history","analysis":"/api/acts/ad-bae-146-134-horizontal-stabiliser-lower-skin-joint-plates/analysis","conflicts":"/api/acts/ad-bae-146-134-horizontal-stabiliser-lower-skin-joint-plates/conflicts","importantCases":"/api/acts/ad-bae-146-134-horizontal-stabiliser-lower-skin-joint-plates/important-cases","documents":"/api/acts/ad-bae-146-134-horizontal-stabiliser-lower-skin-joint-plates/documents"}}