{"id":"F2006B02806","name":"AD/B737/102 - Flap Control Cable Failure Detection System","slug":"ad-b737-102-flap-control-cable-failure-detection-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42148,"registerId":"commonwealth-F2006B02806-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/102 - Flap Control Cable Failure Detection System","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBoeing 737 Series Aeroplanes\n\nAD/B737/102 Flap Control Cable Failure Detection System 5/97\n\nApplicability: Model 737-300, \\-400, and \\-500 series aircraft with line numbers 1001 through 2765.\n\nRequirement: Remove the shim, if installed, from behind the proximity switch in the system which detects a loss of tension in the cable controlling the flaps; and trim the switch bracket; in accordance with Boeing Alert Service Bulletin 737-27A1199.\n\nNote: FAA AD 97-02-16 Amdt 39-9901 refers.\n\nCompliance: Unless already accomplished, within 18 months or 3,200 hours time in service after 24 April 1997, whichever occurs first.\n\nThis Airworthiness Directive becomes effective on 24 April 1997.\n\nBackground: The FAA received reports that the affected proximity switch bracket can impair the movement of a pulley arm mechanism, ultimately preventing the detection system from operating. This event could result in movement of the flaps without action by the pilot, and ultimately cause reduced controllability of the aircraft.","sortOrder":0}],"analysis":{"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 models. It has not expanded beyond its original purpose of mandating a particular hardware modification."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined term implicitly used ('line numbers' referring to production sequence)","Single, clear mechanical requirement with no conditional logic or exceptions","No cross-references to other legislation (only references to Boeing technical bulletin and FAA AD for information)","Straightforward compliance deadline with simple alternative calculation (time OR hours)"],"plain_english_summary":"This mandatory Airworthiness Directive orders operators of Boeing 737-300/-400/-500 (line numbers 1001–2765) to remove a shim and trim a proximity-switch bracket per Boeing Alert SB 737-27A1199. The shim can foul a pulley and prevent the flap cable tension sensor from detecting cable loss, risking uncommanded flap movement and loss of control. Compliance is required within 18 months or 3,200 flight hours from 24 April 1997."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"No. The directive implements a narrowly targeted corrective action described in the Background: it addresses a specific proximity-switch/bracket interference for identified 737 line numbers by mandating shim removal and bracket trimming per Boeing's service bulletin, without extending applicability beyond the listed models and line numbers."},"complexity_factors":["Narrow, explicit applicability by model and line numbers (Applicability).","Single, small-scale hardware modification mandated; technical specificity requires maintenance action (Requirement).","Compliance deadline uses two metrics (18 months or 3,200 hours), requiring operators to track both (Compliance).","Relies on an external Boeing Alert Service Bulletin for procedural detail, creating a dependency on manufacturer documentation (Requirement).","Safety-critical context increases operational sensitivity and potential aircraft downtime during compliance (Background/Compliance).","Cross-reference to FAA AD increases regulatory coordination considerations (Note).","Economic burden falls on aircraft operators who must schedule and pay for the modification (implicit from Requirement/Compliance)."],"plain_english_summary":"This directive requires operators of Boeing 737-300, -400 and -500 aeroplanes (line numbers 1001–2765) to remove a shim behind the flap-control proximity switch and trim the switch bracket, following Boeing Alert Service Bulletin 737-27A1199. It responds to reports that the bracket can stop a pulley arm and prevent the cable-tension detection system from working, risking unintended flap movement. Operators must complete the work within 18 months or 3,200 flight hours from 24 April 1997 and will bear the maintenance cost and scheduling impact."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-102-flap-control-cable-failure-detection-system","history":"/api/acts/ad-b737-102-flap-control-cable-failure-detection-system/history","analysis":"/api/acts/ad-b737-102-flap-control-cable-failure-detection-system/analysis","conflicts":"/api/acts/ad-b737-102-flap-control-cable-failure-detection-system/conflicts","importantCases":"/api/acts/ad-b737-102-flap-control-cable-failure-detection-system/important-cases","documents":"/api/acts/ad-b737-102-flap-control-cable-failure-detection-system/documents"}}