{"id":"F2006B03654","name":"AD/BEECH 1900/36 - Flap Flexible Driveshaft Assembly","slug":"ad-beech-1900-36-flap-flexible-driveshaft-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":43244,"registerId":"commonwealth-F2006B03654-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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\nBeechcraft 1900 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/BEECH 1900/36 Flap Flexible Driveshaf","sectionType":"part","heading":"AD/BEECH 1900/36 Flap Flexible Driveshaft Assembly 13/2001","content":"# AD/BEECH 1900/36 Flap Flexible Driveshaft Assembly 13/2001\n\nDM\n\nApplicability: Beech 1900 (S/Nos UA-2 and UA-3),\n\nBeech 1900C (S/Nos UB-1 through UB-74, UC-1 through UC-174 and UD-1 through UD-6), and\n\nBeech 1900D (S/Nos UE-1through UE-345, UE-347 through UE-361, UE-364, UE- 367,\n\nUE-373 and UE-379).\n\nRequirement: Inspect each of four flap flexible driveshaft assemblies for correct diagonal wrap and correct installation in accordance with Raytheon Mandatory Service Bulletin SB 27- 3397. Replace before further flight any driveshaft found to have an incorrect diagonal wrap or found to have been installed incorrectly.\n\nNote: FAA AD 2001-18-07 refers.\n\nCompliance: Unless previously accomplished, with 200 flight hours after the effective date of this Airworthiness Directive.\n\nThis Airworthiness Directive becomes effective on 7 November 2001.\n\nBackground: Failures of the flap flexible driveshaft have occurred, resulting in flap extension or retraction problems. Such a failure could result in an asymmetric flap condition in flight if the flap safety switch fails to function properly.\n\n![](image.002.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 24 October 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 7 November 2001.","sortOrder":1}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in specific aircraft. It has not expanded beyond its initial purpose of correcting flap driveshaft failures in the Beech 1900 series."},"complexity_factors":["Single, specific mechanical issue addressed (flap driveshaft assemblies)","Clear applicability limited to specific aircraft models and serial numbers","Straightforward two-step requirement: inspect, then replace if faulty","Single compliance deadline (200 flight hours from effective date)","No nested exceptions, conditional logic, or extensive cross-referencing","Only one external reference (FAA AD 2001-18-07, noted as informational)","Short document (approximately 250 words excluding headers and signatures)"],"plain_english_summary":"This CASA Airworthiness Directive requires inspection of the four flap flexible driveshaft assemblies on specified Beechcraft 1900, 1900C and 1900D aircraft because incorrect manufacture or installation (wrong diagonal wrap) can lead to driveshaft failure and asymmetric flap deployment. Inspections must be done within 200 flight hours of 7 November 2001, and any incorrectly wrapped or installed assemblies must be replaced before further flight.\n\nIt affects operators and maintenance engineers of the listed 1900s and matters because asymmetric flaps can cause loss of control during takeoff or landing."},"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":2,"scope_assessment":{"changed":false,"description":"The directive remains narrowly focused on inspecting and, if necessary, replacing the flap flexible driveshaft assemblies for the listed Beech 1900-series aircraft. It does not expand beyond that original safety remit: no new aircraft types, no additional systems, and no broader regulatory or commercial measures are introduced. The AD therefore has not grown significantly beyond its original purpose as a targeted corrective safety measure."},"complexity_factors":["Short, single-purpose instrument (one inspection requirement and one corrective action).","Applicability limited to specific serial-number ranges (clear but requires checking serials).","Cross-reference to one external document: Raytheon Mandatory Service Bulletin SB 27‑3397.","Cross-reference to a related FAA AD (FAA AD 2001‑18‑07).","One clear compliance deadline (200 flight hours) and a mandatory ‘replace before further flight’ condition for failed items.","No multiple tiers of exceptions, no nested conditional logic, no extensive defined-terms section."],"plain_english_summary":"**What this directive does (mechanics)**\n\n- **Applies to** specific Beech 1900 series aeroplanes (identified by serial number ranges in the “Applicability” section).  \n- **Requires** an inspection of each of the four flap flexible driveshaft assemblies on the aeroplane to confirm: (a) the driveshaft has the correct diagonal wrap, and (b) it has been installed correctly. The inspection must be carried out in accordance with Raytheon Mandatory Service Bulletin SB 27‑3397. (See “Requirement”.)  \n- **If a driveshaft fails the inspection**, it must be replaced **before further flight**.  \n- **Timing:** the inspection must be done within **200 flight hours** after the AD’s effective date unless it has already been completed. (See “Compliance”.)\n\n**Who is affected**\n\n- Owners/operators of the particular Beech 1900, 1900C and 1900D aircraft listed by serial number in the “Applicability” section.  \n- Maintenance organisations that service these aircraft (they must follow the Raytheon service bulletin when inspecting and, if necessary, replacing parts).  \n- Parts suppliers (Raytheon or authorised distributors) to the extent replacement driveshafts are required.\n\n**Why it matters (safety and operational effect)**\n\n- The Background section states that failures of the flap flexible driveshaft have occurred and have caused flap extension or retraction problems. If the flap safety switch also fails, a driveshaft failure could lead to an asymmetric flap condition in flight (uneven flap deployment), which poses a flight-safety risk.  \n\n**Who pays and who decides**\n\n- Operators pay the direct costs: inspection labour, possible replacement parts, and aircraft downtime while the work is performed.  \n- The Civil Aviation Safety Authority (CASA) delegate issues and enforces the directive; the directive requires compliance with the Raytheon service bulletin (so Raytheon supplies the procedural standard).  \n\n**Practical compliance effects and trade-offs**\n\n- Cost and downtime: operators must schedule inspections within 200 flight hours, which may impose short-term operational disruption and maintenance expense. If replacements are necessary, there is additional parts and labour cost and scheduling impact.  \n- Concentrated vs diffuse effects: the benefits (reduced risk of flap failure) are concentrated on operators and their passengers/crew; costs are concentrated on those same operators. Raytheon (as the author of the service bulletin and supplier of parts) may see increased demand for replacement driveshafts.  \n- Implementation risk: relies on correct application of the Raytheon service bulletin by maintenance organisations and on enforcement by CASA. The directive cross‑references FAA AD 2001‑18‑07 as related guidance.\n\n**Source claims vs mechanical effect**\n\n- The AD’s stated purpose is to correct an unsafe condition caused by driveshaft failures (Background). Mechanically, it mandates inspection and replacement where necessary (Requirement and Compliance). Any claim that the AD will change market structure, prices, or long‑run maintenance practices depends on how many aircraft require replacement and on parts availability; the AD itself only prescribes inspection/replacement, not market controls.\n\n(Referenced sections: Applicability; Requirement; Compliance; Background; Raytheon Mandatory Service Bulletin SB 27‑3397; FAA AD 2001‑18‑07.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-beech-1900-36-flap-flexible-driveshaft-assembly","history":"/api/acts/ad-beech-1900-36-flap-flexible-driveshaft-assembly/history","analysis":"/api/acts/ad-beech-1900-36-flap-flexible-driveshaft-assembly/analysis","conflicts":"/api/acts/ad-beech-1900-36-flap-flexible-driveshaft-assembly/conflicts","importantCases":"/api/acts/ad-beech-1900-36-flap-flexible-driveshaft-assembly/important-cases","documents":"/api/acts/ad-beech-1900-36-flap-flexible-driveshaft-assembly/documents"}}