{"id":"F2006B02796","name":"AD/B727/91 - Leading Edge Slat Actuators - Inspection and Modification","slug":"ad-b727-91-leading-edge-slat-actuators-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42138,"registerId":"commonwealth-F2006B02796-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/91 - Leading Edge Slat Actuators - Inspection and Modification","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)  Boeing 727 Series Aeroplanes\n\n \n\nAD/B727/91 Leading Edge Slat Actuators - Inspection\n\nand Modification\n\n\n2/83\n\n \n\nApplicability: All model 727 aircraft equipped with Decoto leading edge actuators P/N 10-61792-1,\n\n-2, -4, -5, -7 or -8.\n\n \n\nDocument: FAA AD 82-22-01 Amdt. 39-4477.\n\n \n\nNote: Boeing SB 727-27-209 Rev. 1 and Decoto SB 27-109 refer.\n\n \n\nCompliance: As per requirement document.\n\n \n\nBackground: One operator found fatigue cracking of the piston of a leading edge slat actuator assembly manufactured by Decoto Aircraft, Inc. Separation of the piston at the extend lock ring groove, where cracking was detected, could result in extension of the associated slat.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive’s scope, as stated in the text, is to require inspection and modification of Decoto leading edge slat actuators on Boeing 727 aircraft with the listed part numbers to address fatigue cracking found in a piston. The text directs operators to comply with FAA AD 82-22-01 Amdt. 39-4477 and cites Boeing and Decoto service bulletins as references. There is no indication in the supplied text that the directive’s scope has been broadened or narrowed from that stated purpose. [Applicability] [Background] [Document] [Note] [Compliance]"},"complexity_factors":["Technical specificity of the safety issue (fatigue cracking at the actuator piston extend lock ring groove) [Background]","Directive references external documents for required actions (FAA AD 82-22-01 Amdt. 39-4477) rather than containing full procedures itself [Document] [Compliance]","Cross-referencing of multiple service bulletins (Boeing and Decoto) that technicians must consult to complete work correctly [Note]","Narrow applicability defined by specific part numbers and aircraft model, requiring accurate records and parts traceability [Applicability]","Operational impacts from required inspections/modifications (downtime, parts procurement, specialist labour) [Document] [Compliance]","Enforcement occurs within an aviation regulatory framework, adding administrative compliance responsibilities to technical ones [Document] [Compliance]"],"plain_english_summary":"This directive requires inspection and modification of certain Decoto leading‑edge slat actuators installed on Boeing 727s, directing operators to comply with FAA AD 82‑22‑01 (which contains the specific inspection/modification procedures and compliance times). It was issued after a fatigue crack was found in an actuator piston that could permit unintended slat extension.\n\nAffected operators must obtain the referenced FAA AD and service bulletins, pay for and schedule the mandated work, and accept the associated maintenance cost and downtime."},"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 specific aircraft components. It has not expanded beyond its original purpose of mandating inspection and modification of Decoto leading edge slat actuators on Boeing 727 aircraft."},"complexity_factors":["Very short document (approximately 200 words)","Only 6 specific part numbers to identify applicability","Single technical requirement (inspect and modify)","No defined terms section","No nested conditional logic or exceptions","References external documents rather than reproducing technical specifications","Clear, single-purpose safety directive with straightforward compliance pathway"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety notice issued by Australia's Civil Aviation Safety Authority (CASA) for specific Boeing 727 aircraft.\n\n**What it requires:** Owners and operators of Boeing 727 planes fitted with certain Decoto-brand leading edge slat actuators (parts numbered 10-61792-1, -2, -4, -5, -7, or -8) must inspect and modify these components according to instructions from the US Federal Aviation Administration (FAA).\n\n**Why it matters:** A leading edge slat is a movable panel on the front of the wing that helps with lift during takeoff and landing. The actuator is the hydraulic device that moves it. Fatigue cracking was found in the piston of one of these actuators — specifically where a locking ring sits. If the piston breaks at this point, the slat could extend unexpectedly during flight, potentially causing loss of control or structural damage.\n\n**Who must comply:** Anyone operating a Boeing 727 with the specified Decoto actuators. The directive references Boeing Service Bulletin 727-27-209 and Decoto Service Bulletin 27-109 for technical details, and FAA AD 82-22-01 for the specific compliance requirements."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-91-leading-edge-slat-actuators-inspection-and-modification","history":"/api/acts/ad-b727-91-leading-edge-slat-actuators-inspection-and-modification/history","analysis":"/api/acts/ad-b727-91-leading-edge-slat-actuators-inspection-and-modification/analysis","conflicts":"/api/acts/ad-b727-91-leading-edge-slat-actuators-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-b727-91-leading-edge-slat-actuators-inspection-and-modification/important-cases","documents":"/api/acts/ad-b727-91-leading-edge-slat-actuators-inspection-and-modification/documents"}}