{"id":"F2006L02833","name":"AD/TB20/45 - Wing Spar Lower Boom","slug":"ad-tb20-45-wing-spar-lower-boom","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":60060,"registerId":"commonwealth-F2006L02833-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Aerospatiale (Socata) TB20 (Trinidad) Se","sectionType":"division","heading":"Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes","content":"### Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\n| AD/TB20/45 | Wing Spar Lower Boom | 10/2006 |\n| ---------- | -------------------- | ------- |\n\n| Applicability: | Model TB 20 and TB 21 aircraft, all serial numbers; without repair No. REP 20.031 implemented on both left hand and right hand sides.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Inspect the wing spar lower boom in accordance with the Accomplishment Instructions of SOCATA Service Bulletin No. 10-148 original issue, or later EASA approved revision.When defect dimensions exceed the limits specified in the Requirement document, or if the defect is located out of the area depicted in Figure 2 of the Requirement document, then the Type 1 or Type 2 repairs are not valid. A written report shall then be sent to the manufacturer as specified in paragraph A.5). In this case, further flight is prohibited until SOCATA provides a repair solution or otherwise agrees to further flight.Note: EASA AD 2006-0123 refers. |\n| Compliance:    | Within 100 flight hours or one year after 28 September 2006, whichever occurs first.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n|                | This Airworthiness Directive becomes effective on 28 September 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| Background:    | Reports were received of interference between the wing spar lower boom and wheel fairing attaching screw. Such interference, unless corrected, could reduce the fatigue life of the wing spar.                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n28 July 2006","sortOrder":0},{"sectionNumber":"AD/TB20/45","sectionType":"part","heading":"AD/TB20/45","content":"## AD/TB20/45","sortOrder":1},{"sectionNumber":"Wing Spar Lower Boom","sectionType":"part","heading":"Wing Spar Lower Boom","content":"## Wing Spar Lower Boom","sortOrder":2},{"sectionNumber":"10/2006","sectionType":"part","heading":"10/2006","content":"## 10/2006","sortOrder":3}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive targets the specific interference issue between the wing spar lower boom and a wheel fairing screw reported in the background. It confines action to TB20/TB21 airframes without REP 20.031 and prescribes inspection, reporting, and a flight prohibition until the manufacturer provides an acceptable repair; it does not expand obligations beyond addressing that defect (Applicability; Requirement; Background)."},"complexity_factors":["Narrow applicability (TB20/TB21 without repair REP 20.031) increases clarity but requires fleet-level record checks (Applicability).","References an external service document (SOCATA Service Bulletin No. 10-148) and allows later EASA-approved revisions, requiring access to and reliance on that technical material (Requirement).","Numeric defect limits and a depicted area determine whether standard Type 1/2 repairs apply, creating a technical judgement about dimensions and locations (Requirement).","Mandated written reporting to the manufacturer and an immediate prohibition on further flight until SOCATA agrees to a repair imposes operational and potential grounding costs on operators (Requirement; Compliance).","Cross-reference to EASA AD 2006-0123 and paragraph A.5 reporting requirement adds layers of regulatory linkage and procedural steps (Requirement)."],"plain_english_summary":"Mandates that owners/operators of Socata TB20 and TB21 aeroplanes (all serial numbers) without repair REP 20.031 inspect the wing spar lower boom following SOCATA Service Bulletin No. 10‑148 within 100 flight hours or one year after 28 September 2006. If defects exceed the bulletin’s limits or lie outside the depicted area, the bulletin repairs are invalid, operators must report to the manufacturer and no further flight is allowed until SOCATA provides or approves a repair (Requirement; Compliance). This responds to reported interference that could shorten the spar’s fatigue life (Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with narrow, targeted scope. It addresses a specific structural safety issue on specific aircraft models without expanding beyond its original safety purpose."},"complexity_factors":["Single specific aircraft model applicability (TB20/TB21 series)","References external technical documents (SOCATA Service Bulletin No. 10-148, EASA AD 2006-0123) without reproducing their content","Conditional logic for repair validity based on defect dimensions and location","Simple binary compliance deadline (100 flight hours OR one year)","No defined terms section or extensive interpretation provisions","Short, single-purpose directive focused on one specific safety issue"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of certain Aerospatiale (SOCATA) TB20 and TB21 aircraft to inspect the wing spar lower boom per SOCATA Service Bulletin No. 10-148 within 100 flight hours or one year after 28 Sep 2006. \n\nIf damage exceeds the service bulletin’s limits or is outside allowed locations, the aircraft must be grounded and the manufacturer notified and must approve any repair. It addresses risk from wheel-fairing screws rubbing and shortening wing fatigue life."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-45-wing-spar-lower-boom","history":"/api/acts/ad-tb20-45-wing-spar-lower-boom/history","analysis":"/api/acts/ad-tb20-45-wing-spar-lower-boom/analysis","conflicts":"/api/acts/ad-tb20-45-wing-spar-lower-boom/conflicts","importantCases":"/api/acts/ad-tb20-45-wing-spar-lower-boom/important-cases","documents":"/api/acts/ad-tb20-45-wing-spar-lower-boom/documents"}}