{"id":"F2006B06952","name":"AD/SF340/23 - Nacelle Cowling Door","slug":"ad-sf340-23-nacelle-cowling-door","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114850,"registerId":"commonwealth-F2006B06952-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/SF340/23 - Nacelle Cowling Door","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  SAAB SF340 Series Aeroplanes\n\n \n\nAD/SF340/23 Nacelle Cowling Door 3/91\n\nApplicability: Model 340A and 340B with serial numbers; SAAB 340A-004 through -159.\n\nSAAB 340B-160 through -200.\n\n \n\nRequirement: Action in accordance with the technical requirements of Swedish LFV AD 1-042.\n\n \n\nNote: SAAB-SCANIA AB SB SAAB 340-71-35 refers.\n\n \n\nCompliance: As specified in the Requirement Document with revised effective date 21 March 1991.\n\n \n\nBackground: The latch triggers on the nacelle fwd cowling doors have on some aircraft been trimmed to make the latch fit the form of the cowling surface. This could cause abnormal abrasion on the triggers, and might cause the latches to come unlocked, and result in cowling door opening during flight.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Scope aligns with the Swedish LFV AD and the SAAB service bulletin and is confined to the listed SAAB 340A/340B serial numbers; the directive implements that external airworthiness action without expanding applicability beyond the specified aircraft or adding new categories of measures."},"complexity_factors":["Cross-references external mandatory documents (Swedish LFV AD 1-042 and manufacturer service bulletin) — requires obtaining and following outside material.","Applicability limited to specific serial-number ranges — necessitates operator record checks to determine coverage.","Technical remedy is not reproduced in this AD text — maintenance organisations must interpret and apply external technical instructions.","Compliance tied to a revised effective date (21 March 1991) — creates administrative scheduling and tracking obligations.","Safety-critical hardware work (latch inspection/repair) requires qualified maintenance personnel and possible parts, introducing direct operator costs."],"plain_english_summary":"This airworthiness directive requires operators of specified SAAB 340A and 340B aeroplanes (listed by serial number) to perform the technical inspections and corrective actions set out in Swedish LFV AD 1-042 (see also SAAB Service Bulletin SAAB 340-71-35). It responds to worn or trimmed nacelle forward-cowling door latch triggers that can abrade, unlock and allow a cowling door to open in flight. Aircraft operators and maintenance organisations must follow the requirement document (effective 21 March 1991) and bear the cost and scheduling burden of inspections and repairs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of ensuring proper latch maintenance on SAAB SF340 nacelle cowling doors."},"complexity_factors":["Very short document (under 200 words)","Only 2 defined applicability criteria (model and serial number ranges)","Single requirement referencing external technical document","No nested conditions or exceptions","No cross-references to other legislation beyond one external Swedish AD and one service bulletin","Straightforward compliance deadline (single date)"],"plain_english_summary":"**What this is:** An Airworthiness Directive (AD) — essentially a mandatory safety order for aircraft.\n\n**What it does:** Requires owners and operators of specific SAAB SF340 aircraft (models 340A and 340B with certain serial numbers) to inspect and fix a problem with the engine cowling doors.\n\n**The problem:** Some maintenance crews had been trimming the latch triggers on the forward engine cowling doors to make them fit flush with the cowling surface. This \"custom fitting\" wears down the latches abnormally and could cause them to unlock mid-flight — potentially leading to the cowling door flying open during flight.\n\n**What must happen:** Aircraft operators must follow the technical instructions in a Swedish aviation safety document (LFV AD 1-042) to correct this issue.\n\n**Who it affects:** Airlines and operators flying SAAB 340A aircraft (serial numbers 004–159) and 340B aircraft (serial numbers 160–200).\n\n**Why it matters:** A cowling door opening in flight could cause serious damage to the aircraft or even lead to loss of control. This directive prevents that by ensuring latches aren't improperly modified."}},"importantCases":[],"_links":{"self":"/api/acts/ad-sf340-23-nacelle-cowling-door","history":"/api/acts/ad-sf340-23-nacelle-cowling-door/history","analysis":"/api/acts/ad-sf340-23-nacelle-cowling-door/analysis","conflicts":"/api/acts/ad-sf340-23-nacelle-cowling-door/conflicts","importantCases":"/api/acts/ad-sf340-23-nacelle-cowling-door/important-cases","documents":"/api/acts/ad-sf340-23-nacelle-cowling-door/documents"}}