{"id":"F2006B11195","name":"AD/LYC/103 - Slick Magneto Inspection","slug":"ad-lyc-103-slick-magneto-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56904,"registerId":"commonwealth-F2006B11195-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/LYC/103 - Slick Magneto Inspection","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nLycoming Piston Engines\n\nAD/LYC/103 Slick Magneto Inspection 4/99 DM\n\nApplicability: Textron Lycoming O-540-B2B5, \\-B2C5, \\-E4B5, \\-E4C5, \\-G1A5, \\-G2A5,\n\nIO-540-K1A5, \\-K1B5 and \\-K1G5 reciprocating engines equipped with Slick Aircraft Products magneto Model Numbers 6251, 6252, 6255, 6351 and 6355.\n\nNote: These engines are known to be installed on, but not limited to the following aeroplanes:\n\nManufacturer Aeroplane Model and/or Series\n\nBritten Norman BN-2A, \\-2A-2, \\-2A-3, \\-2A-6, \\-2A-9, \\-2A-20, \\-2A-21, 2A-26,\n\n\\-2A-27, \\-2A-MKIII, \\-2A-MKIII-2, \\-2A-MKIII-3, \\-2B-20,\n\n\\-2B-21, \\-2B-26 and \\-2B-27\n\nPiper PA-25-235, PA-25-260, PA-32( )-260 and PA-32-300\n\nRequirement: 1. For engines on which the service history of the magneto is not known or on which the magneto has greater than 250 hours time in service (TIS) since new, factory rebuilt or overhauled, on the effective date of this Directive, inspect the components of the magneto impulse coupling for the conditions listed in accordance with steps 1 through 7 of Textron Lycoming Mandatory Service Bulletin (MSB) No 537 dated 20 November 1998.\n\nNote: Textron Lycoming MSB No 537 dated 20 November 1998 contains Slick Service Bulletin No SB1-98 dated 26 August 1998. The steps referenced in the Textron MSB are the same steps referenced in the Slick Bulletin.\n\n    2. For engines on which the magneto has less than or equal to 250 hours TIS since new, factory rebuilt or overhauled, on the effective date of this Directive, inspect the components of the magneto impulse coupling for the conditions listed in accordance with steps 1 through 7 of Textron Lycoming Mandatory MSB No 537.\n\n    3. Remove the magneto impulse coupling from service and replace it with a serviceable coupling.\n\nNote: FAA AD 99-04-04 Amdt 39-11028 refers.\n\nCompliance: 1. Within 10 hours TIS from the effective date of this directive and thereafter at intervals not to exceed 250 hours TIS.\n\n    2. Either prior to accumulating 250 hours TIS since new, factory rebuilt or overhauled, or within 10 hours TIS from the effective date of this Directive, whichever comes later, and thereafter at intervals not to exceed 250 hours TIS.\n\n    3. Prior to the accumulation of 2 000 hours TIS since new.\n\nThis Airworthiness Directive becomes effective on 24 February 1999.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: Numerous reports have been received of failure of the impulse coupling pawl on Slick magnetos installed on Textron Lycoming IO-540 and O-540 engines. The impulse coupling failure has resulted in seizure of the engine.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical failure mode in specific engine/magneto combinations. The scope remains precisely focused on the impulse coupling inspection and replacement requirements as originally intended. No scope creep is evident."},"complexity_factors":["Short, single-purpose directive focused on one specific mechanical component","Only 3 main requirements with clear conditional logic based on hours-in-service thresholds","Minimal cross-referencing — only references one Textron Lycoming Service Bulletin and one FAA AD for context","Straightforward applicability section listing specific engine and magneto model numbers","No nested exceptions or complex defined terms — 'TIS' (Time in Service) is the only technical abbreviation used, and it's self-explanatory in context","Clear compliance timeline with simple 'whichever comes later' logic in Requirement 2"],"plain_english_summary":"CASA mandates that owners/operators of aircraft with specified Lycoming O‑540/IO‑540 engines fitted with Slick magnetos inspect and replace faulty magneto impulse couplings on a short timetable and replace couplings before 2,000 hours. This is a compulsory safety directive, not optional.\n\nIt affects Britten Norman Islander and listed Piper aircraft, and their maintenance teams — issued after reports of impulse‑coupling failures that can cause complete engine seizure in flight."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains narrowly focused on inspecting and, where necessary, replacing the impulse coupling in specified Slick magnetos on certain Lycoming O‑540 and IO‑540 engines. The directive addresses a single, safety‑critical defect (impulse coupling pawl failure) and does not expand into unrelated regulatory areas or broader airworthiness requirements. Its instruments (inspection intervals, a final replacement limit, and references to manufacturer service bulletins) are consistent with the AD’s stated safety objective and do not materially broaden the original purpose."},"complexity_factors":["Short, single-issue AD focused on impulse coupling on specified Slick magneto models","Applicability lists multiple engine model suffixes and several magneto model numbers","References external documents for the actual inspection steps (Textron Lycoming MSB No. 537 and Slick SB1-98)","Three distinct conditional requirements based on magneto time-in-service (unknown, >250 hours, ≤250 hours)","Multiple compliance timing rules (inspect within 10 hours, then every 250 hours; alternate initial deadline for ≤250 TIS; replacement prior to 2,000 hours)","Cross-reference to FAA AD 99-04-04 (informational)","No extensive nested exceptions or numerous defined terms within the AD itself"],"plain_english_summary":"**What this directive does**\n\n- This Airworthiness Directive (AD) orders repeated inspections and, where necessary, replacement of the impulse coupling (a small mechanical part inside the magneto that helps start and provide ignition timing) on certain Slick magnetos fitted to specific Textron Lycoming O‑540 and IO‑540 piston engines. (See Requirement 1–3 and Compliance 1–3.)\n\n**Who it affects**\n\n- Aircraft owners and operators of aeroplanes using the listed Lycoming engines fitted with Slick magneto models 6251, 6252, 6255, 6351 and 6355. The AD notes some typical aircraft types affected (for example, certain Britten Norman BN‑2 and Piper PA‑32 series), but applies to the listed engines wherever installed. (Applicability section.)\n\n**Why it matters**\n\n- The AD responds to reports that the impulse coupling pawl on these Slick magnetos can fail and has caused engine seizure. The directive requires inspections and replacement before the coupling fails, with the stated safety objective of preventing engine seizure. (Background; Requirement.)\n\n**What you must do, in plain steps**\n\n- Inspect the impulse coupling components following the detailed steps in Textron Lycoming Mandatory Service Bulletin (MSB) No. 537 (which incorporates Slick Service Bulletin SB1‑98). The AD explicitly directs use of those steps. (Requirement 1–2; Note.)\n- If the magneto’s service history is unknown or the magneto has more than 250 hours time‑in‑service (TIS) since new/factory rebuilt/overhauled on the AD effective date, inspect within 10 hours TIS of the AD and then at intervals not exceeding 250 hours TIS. (Requirement 1; Compliance 1.)\n- If the magneto had 250 hours TIS or less on the AD effective date, inspect either before it accumulates 250 hours TIS or within 10 hours TIS from the AD effective date (whichever is later), then at intervals not exceeding 250 hours TIS. (Requirement 2; Compliance 2.)\n- Remove the impulse coupling from service and replace it with a serviceable coupling prior to the accumulation of 2,000 hours TIS since new. (Requirement 3; Compliance 3.)\n\n**Mechanics of compliance and source material**\n\n- The inspection procedure is not reproduced in full in the AD; it is implemented by following Textron Lycoming MSB No. 537 (20 Nov 1998), which references Slick Service Bulletin SB1‑98 (26 Aug 1998). Operators must have access to that MSB to perform the mandated inspections. (Requirement note.)\n\n**Costs, incentives and trade‑offs (practical testing of the AD’s purpose)**\n\n- Who pays: aircraft owners/operators pay inspection labour, any replacement coupling parts, and aircraft downtime. (Requirement & Compliance.)\n- Incentives: by mandating inspections and a hard replacement limit (2,000 hours TIS), the directive creates a clear compliance incentive to replace suspect couplings before failure. Owners face a near‑term compliance cost if the magneto’s history is unknown or already >250 hours TIS. (Compliance 1–3.)\n- Implementation risk: compliance requires access to the Lycoming/Slick service bulletins. If those bulletins are not on hand, inspections may be delayed or performed improperly. Supply constraints for replacement couplings or limited access to qualified maintenance providers could lengthen downtime. (Requirement note; practical inference.)\n- Compliance burden and administrative discretion: the AD prescribes what to inspect and when but relies on the published MSB for the detailed procedure; that MSB determines the technical threshold for a coupling being serviceable or unserviceable. The regulator’s role is to mandate compliance; judgement about serviceability may rest with maintenance engineers following the MSB. (Requirement; Compliance.)\n- Effects on private choice and market actors: independent maintenance providers can perform the inspections and replace couplings so long as they follow the MSB; the AD does not explicitly require factory overhaul for replacement parts, only a ‘‘serviceable coupling,’’ which leaves room for non‑factory suppliers if they meet serviceability standards. This creates a demand for compatible couplings and for maintenance capacity, which could raise short‑term costs and benefit parts suppliers and maintenance businesses. (Requirement 3.)\n- Concentrated benefits, diffuse costs: the primary benefit (reduced risk of seizure) accrues to the operators and to passengers and third parties who would be affected by an in‑flight engine seizure. The cost (inspections, replacements, downtime) is concentrated on the specific group of affected owners/operators. (Background; Compliance.)\n\n**Bottom line**\n\n- The AD sets a clear, time‑based inspection and replacement regime for the impulse coupling on specified Slick magnetos to reduce the risk of engine seizure. Compliance requires following Lycoming/Slick service bulletin steps, performing recurring inspections every 250 hours TIS, and replacing the coupling before 2,000 hours TIS. Operators should budget for inspection labour, parts, and aircraft downtime, and ensure maintenance personnel have the referenced service bulletins available. (Requirement; Compliance; Note.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-103-slick-magneto-inspection","history":"/api/acts/ad-lyc-103-slick-magneto-inspection/history","analysis":"/api/acts/ad-lyc-103-slick-magneto-inspection/analysis","conflicts":"/api/acts/ad-lyc-103-slick-magneto-inspection/conflicts","importantCases":"/api/acts/ad-lyc-103-slick-magneto-inspection/important-cases","documents":"/api/acts/ad-lyc-103-slick-magneto-inspection/documents"}}