{"id":"F2006B04458","name":"AD/BELL 206/143 Amdt 3 - Tail Boom Skin","slug":"ad-bell-206-143-amdt-3-tail-boom-skin","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44295,"registerId":"commonwealth-F2006B04458-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/143 Amdt 3 - Tail Boom Skin","content":"![](image.001.png)Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\n![](image.002.png)![](image.002.png)AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/BELL 206/143 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| AD/BELL 206/143Amdt 3         | Tail Boom Skin                                      | 5/2000DM |\n| ----------------------------- | --------------------------------------------------- | -------- |\n| Applicability: Applies to the | following BHTC Model 206L series helicopters:       |          |\n| Models                        | Serial Numbers                                      |          |\n| 206L                          | 45004 through 45049, 45051 through 45153, and 46601 |          |\n|                               | through 46617                                       |          |\n| 206L-1                        | 45154 through 45790                                 |          |\n| 206L-3                        | 51001 through 51612                                 |          |\n| 206L-4                        | 52001 through 52163, 52165 through 52212, and 52214 |          |\n|                               | through 52216                                       |          |\n\nRequirement: 1. Perform a visual inspection of the tail boom in accordance with BHTC Alert Service Bulletin (ASB) 206L-98-114 or ASB 206L-98-114 Revision A.\n\n    2. Accomplish the following:\n\n    Remove the upper and lower supports of the horizontal stabiliser in accordance with the applicable Maintenance Manual.\n\n    b. In accordance with section 6.2 of Standard Practices Manual BHT-ALL-SPM, perform a one-time fluorescent penetrant inspection of the tail boom skin in the area at least 20 mm around the edges of the horizontal stabiliser openings.\n\n    3. Remove the support plates and visually inspect the entire edge of the horizontal stabiliser opening on both sides of the tail boom for cracks, using a 10x magnifying glass.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nIf any crack is found on the tail boom skin as a result of the above required inspections, replace the tail boom before further flight.\n\n    4. Modify the tail boom in accordance with Parts I, II, and III of Alert Service Bulletin 206L-99-115 Revision D, dated 26 January 2000.\n\nNote: Transport Canada AD CF-98-42R3 refers.\n\nCompliance: 1. Unless the initial inspection is already accomplished, before further flight after 29 March 2000; thereafter, inspect before the first flight of each day in accordance with ASB 206L-98-114 Revision A.\n\n    2. Unless already accomplished, before further flight after 29 March 2000.\n\n    3. Within 100 hours time in service after 31 March 1999, and thereafter at intervals not to exceed 110 hours time in service.\n\n    4. Before 31 December 2000, unless already accomplished.\n\nCompliance with Requirement 4 of this Directive constitutes terminating action for Requirements 1, 2, and 3.\n\nThe visual inspection required by this Directive may be performed by the pilot in command, in which case certification is to be made by entering AD/BELL 206/143 Amdt 3 against the daily inspection certification of the maintenance release. A copy of this Airworthiness Directive is to be kept in the aircraft.\n\nThe compliance of the previous issue of this Directive remains unchanged for Requirement 3.\n\nThis Amendment becomes effective on 29 March 2000.\n\nBackground: There have been seven reports of cracks to the tail boom skin in the area of the horizontal stabiliser. The cracks were found by normal visual inspection. The average time accumulated on the tail booms was more than 2,000 hours; however, cracks could develop at any time. Pending further terminating action, on-going repetitive inspections are necessary.\n\nAmendment 1 was issued after a review of crack growth rates indicated a need to detect cracks earlier. This necessitates the use of non-destructive inspections of the tail boom skin under the support plates. Additionally, applicability was expanded for the Model 206L helicopters. The required inspections were an interim measure pending forthcoming mandatory installation of doublers on the tail boom skin around the horizontal stabiliser cutout.\n\nAmendment 2 mandated the reinforcement of the tail boom skin around the left horizontal stabiliser cutout.\n\nAmendment 3 is issued in response to a new TC AD which clarifies the applicability of Model 206 L serial numbers and extends the Requirement 4 compliance time.\n\nAmendment 2 of this Airworthiness Directive became effective on 7 October 1999\\. Amendment 1 of this Airworthiness Directive became effective on 31 March 1999.\n\nThe original issue of this Airworthiness Directive became effective on 20 January 1999.\n\n![Signature: Bernard Malcolm Hole](image.003.png)  \n\nBernard Malcolm Hole\n\nDelegate of the Civil Aviation Safety Authority 23 March 2000\n\n![](image.002.png)The above AD is notified in the Commonwealth of Australia Gazette on 29 March 2000.","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":true,"description":"The legislation has grown beyond its original scope through three amendments. Originally issued in January 1999 as an interim measure requiring repetitive visual inspections, it has expanded to: (1) mandate non-destructive testing using fluorescent penetrant methods (Amendment 1), (2) require physical reinforcement/doubler installation on the left side (Amendment 2), and (3) expand serial number applicability and extend compliance deadlines (Amendment 3). What began as temporary monitoring has become a comprehensive mandatory modification program with permanent structural fixes."},"complexity_factors":["Multiple amendment history requiring cross-referencing (original issue plus Amendments 1, 2, and 3)","Four distinct requirements with different compliance methods and deadlines","Specific serial number applicability across four model variants with non-contiguous ranges","Conditional logic: 'unless already accomplished' clauses and terminating action provisions","Reference to external technical documents (Alert Service Bulletins, Maintenance Manuals, Standard Practices Manual) without reproducing their content","Mixed compliance timeframes: calendar dates, flight hours, and 'before further flight' triggers","Special provision allowing pilot-performed inspections with specific certification requirements"],"plain_english_summary":"This safety order replaces Amendment 2 and mandates owners/operators of specified Bell 206L-series helicopters (listed by serial number) to inspect and repair a cracking defect where the tail boom meets the horizontal stabiliser. It requires daily visual checks, more detailed dye and magnified inspections, and a permanent reinforcement plate modification as the terminating action.\n\nCracks were found on multiple helicopters and could cause tail‑boom failure and loss of control; inspections are immediate and the permanent fix has a year‑end deadline."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"This Amendment (Amdt 3) primarily clarifies serial number applicability for Model 206L helicopters and extends the compliance time for Requirement 4 (the modification). It does not add new categories of action beyond the existing program of inspections and the reinforcement modification that were the original intent of the AD. The instrument remains focused on detecting and correcting tail boom skin cracks and on mandating reinforcement as the terminating action (Background; Amendment 3 description)."},"complexity_factors":["Applicability lists multiple models with several serial number ranges (model/serial specificity increases administrative complexity)","Four separate Requirements with mixed inspection, non‑destructive testing (FPI), and structural modification actions","Multiple cross‑references to manufacturer documents (ASB 206L‑98‑114, ASB 206L‑99‑115 Rev D, Maintenance Manual, Standard Practices Manual BHT‑ALL‑SPM sec 6.2)","Conditional logic: terminating action (Requirement 4) cancels earlier Requirements 1–3; different compliance deadlines depending on whether prior work already done","Different inspection intervals and deadlines (daily visual inspections, 100/110 hour intervals, fixed calendar deadline for modification) add scheduling complexity","Permission for pilot‑performed daily inspection with specific certification entry procedure increases procedural variation"],"plain_english_summary":"**What this instrument does (mechanics)\n\n- It is an Airworthiness Directive (AD) that applies to specific Bell 206L-series helicopters by serial number (see Applicability). The AD requires recurring inspections of the tail boom skin around the horizontal stabiliser cutout, a one‑time non‑destructive inspection under the stabiliser supports, and ultimately a modification (installation of reinforcement/doublers) to the tail boom. (Requirements 1–4; Compliance)\n\n- Immediate actions required are: a visual inspection per BHTC Alert Service Bulletin (ASB) 206L‑98‑114 (or Revision A) and removal of the stabiliser supports to allow a fluorescent penetrant inspection (FPI) of the skin at least 20 mm around the stabiliser opening (Requirement 1–2). If any crack is found, the tail boom must be replaced before the helicopter flies again (Requirement 3).\n\n- The AD requires completion of Parts I–III of ASB 206L‑99‑115 Revision D (the reinforcing modification) by the specified date; once that modification is done it ends (is the \"terminating action\" for) the recurring inspections. (Requirement 4; Compliance)\n\n**Who this affects and who decides\n\n- Who decides: the Civil Aviation Safety Authority (CASA) delegate issued the AD under CAR 1998 subregulation 39.1(1) (preamble). The AD references manufacturer service/maintenance documents (ASBs, Maintenance Manual, Standard Practices Manual) as the instructions to follow (Requirements and Notes).\n\n- Who pays / who acts: owners and operators of the affected Bell 206L helicopters are responsible for carrying out the inspections, any required repairs or replacement, and the modification. Maintenance organisations or qualified personnel must perform the FPI and the modification work; daily visual inspections may be done by the pilot in command and recorded in the aircraft’s daily inspection certification. (Compliance; Note on pilot inspection)\n\n**Why it matters (stated purpose, tested against implementation costs and trade‑offs)\n\n- Stated purpose: the AD responds to multiple reports of cracks in the tail boom skin around the horizontal stabiliser opening. The inspections and modification are intended to detect and correct cracks that could compromise structural integrity (Background).\n\n- Costs and incentives: operators face recurring labour and downtime costs while conducting frequent inspections (daily visual checks and repetitive FPI/10x checks every 100–110 flight hours until modification). If a crack is found, parts and replacement labour are required immediately. The mandatory modification has an upfront cost and scheduled downtime but ends the need for repetitive inspections (Requirement 4; Compliance).\n\n- Implementation risks and compliance burden: the FPI and the structural modification require trained maintenance personnel and adherence to the referenced ASBs and Standard Practices Manual. Allowing pilots to perform the daily visual check reduces immediate maintenance workload but places reliance on non‑specialist detection for an issue that can require specialist NDT to find early cracks (Requirement 1; Compliance).\n\n- Effects on service providers and markets: maintenance shops and authorised repair facilities will perform the FPI and modification work and thus capture business from affected operators. Operators must choose between ongoing inspection costs and a one‑off modification cost; some may opt to retire or restrict use of higher‑hour airframes instead.\n\n**Key operational details (short references)\n\n- Applicability: specific serial numbers for Models 206L, 206L‑1, 206L‑3 and 206L‑4 (Applicability).\n- Inspections: visual per ASB 206L‑98‑114; FPI under support plates per Standard Practices Manual section 6.2; 10x magnifying glass check under removed support plates (Requirements 1–3).\n- Timing: initial inspections before next flight after 29 March 2000 unless already done; recurring checks every 100 hours after a 31 Mar 1999 deadline then every 110 hours; modification to be completed by 31 Dec 2000 unless already done (Compliance).\n- Termination: completing Requirement 4 (the modification) terminates Requirements 1–3.\n\nThis AD establishes a short‑term detection regime (frequent inspections) with a clear path to a permanent fix (structural reinforcement) that transfers ongoing inspection costs into a one‑off modification cost for operators. References: Requirements 1–4; Compliance; Background; Note on pilot inspection."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-143-amdt-3-tail-boom-skin","history":"/api/acts/ad-bell-206-143-amdt-3-tail-boom-skin/history","analysis":"/api/acts/ad-bell-206-143-amdt-3-tail-boom-skin/analysis","conflicts":"/api/acts/ad-bell-206-143-amdt-3-tail-boom-skin/conflicts","importantCases":"/api/acts/ad-bell-206-143-amdt-3-tail-boom-skin/important-cases","documents":"/api/acts/ad-bell-206-143-amdt-3-tail-boom-skin/documents"}}