{"id":"F2006L01019","name":"AD/LYC/115 - Lycoming Crankshaft Replacement","slug":"ad-lyc-115-lycoming-crankshaft-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":58292,"registerId":"commonwealth-F2006L01019-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Lycoming Piston Engines","sectionType":"division","heading":"Lycoming Piston Engines","content":"### Lycoming Piston Engines\n\n| AD/LYC/115 | Lycoming Crankshaft Replacement | 5/2006 |\n| ---------- | ------------------------------- | ------ |\n\n| Applicability: | Lycoming Engines AEIO-360, IO-360, O-360, LIO-360, and LO-360 series reciprocating engines, manufactured new or rebuilt, overhauled, or that had a crankshaft installed after 1 March 1999.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | 1. Check serial number of your engine and crankshaft. If Table 1 of SupplementNo. 1 to Lycoming Mandatory Service Bulletin (MSB) No. 566, dated30 November 2005, lists your engine serial number (SN), use Table 2 of Supplement No. 1 to verify if your crankshaft SN is listed.If Table 1 of Supplement No. 1 to MSB 566 does not list your engine SN, use Table 2 of Supplement No. 1 to verify if your crankshaft SN is listed, if an affected crankshaft was installed as a replacement.2. If Table 2 of Supplement No. 1 lists your crankshaft SN, replace the crankshaft with a crankshaft that is not listed in Table 2 of Supplement No. 1. to Lycoming MSB 566.Note 1: If Lycoming Engines manufactured new, rebuilt, overhauled, or replaced the crankshaft in your engine before 1 March 1999, and you haven't had the crankshaft replaced, no further action is required.Note 2: The engine and crankshaft SNs listed in Table 1 and Table 2 of Supplement No.1 to Lycoming MSB 566 are different from the engine and crankshaft SNs affected by Lycoming MSBs No. 552, No. 553 and No. 566; and CASA ADs AD/LYC/107 and AD/LYC/112.3. Do not install any crankshaft that has a SN listed in Table 2 of Supplement No. 1 to Lycoming MSB 566 into any engine.Note 3: FAA AD 2006-06-16 Amendment 39-14525 refers. |\n| Compliance:    | 1. Unless previously accomplished, within 50 hours time-in-service or 6 months after the effective date of this AD, whichever is earlier.2. Unless previously accomplished, within 50 hours time-in-service or 6 months after the effective date of this AD, whichever is earlier.3. After the effective date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n\n|             | This Airworthiness Directive becomes effective on 11 May 2006.                                                                                                                                                                                                      |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Background: | This AD results from a crankshaft failure in a Lycoming LO-360-A1H6 reciprocating engine. CASA is issuing this AD to prevent failure of the crankshaft, which could result in total engine power loss, in-flight engine failure, and possible loss of the aircraft. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n29 March 2006","sortOrder":0},{"sectionNumber":"AD/LYC/115","sectionType":"part","heading":"AD/LYC/115","content":"## AD/LYC/115","sortOrder":1},{"sectionNumber":"Lycoming Crankshaft Replacement","sectionType":"part","heading":"Lycoming Crankshaft Replacement","content":"## Lycoming Crankshaft Replacement","sortOrder":2},{"sectionNumber":"5/2006","sectionType":"part","heading":"5/2006","content":"## 5/2006","sortOrder":3}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains tightly focused on its original purpose: addressing a specific crankshaft failure risk in defined Lycoming engine models. The scope has not expanded beyond the immediate safety defect."},"complexity_factors":["Multiple cross-references to external documents (Lycoming MSB 566, Supplement No. 1, Tables 1 and 2)","Conditional logic based on manufacturing dates (1 March 1999 cutoff)","Serial number lookup requirements across two different tables depending on engine history","Nested applicability criteria (engine series + manufacturing date + specific serial numbers)","Reference to related but distinct prior directives (AD/LYC/107, AD/LYC/112) and FAA AD 2006-06-16"],"plain_english_summary":"This CASA Airworthiness Directive orders owners/operators of Lycoming AEIO‑360, IO‑360, O‑360, LIO‑360 or LO‑360 engines (manufactured, rebuilt, overhauled, or fitted with a crankshaft after 1 Mar 1999) to check their engine/crankshaft serial numbers against Lycoming MSB 566 Supplement No.1 Table 2. If listed, the crankshaft must be removed and replaced and may not be reinstalled.\n\nA crankshaft failure caused an in‑flight engine loss. Engines with crankshafts last worked before Mar 1999 and untouched since are exempt. Comply within 50 flight hours or six months of effect (11 May 2006)."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD is narrowly targeted to prevent crankshaft failures for a specific set of Lycoming 360-series engines and to remove particular crankshaft serial numbers from service. It stays within that original safety-focused purpose and does not broaden obligations beyond inspection, replacement, and an installation ban tied to the listed serial numbers. The scope has not been expanded beyond the initial intent expressed in the AD (checking and replacing listed crankshafts)."},"complexity_factors":["Dependence on an external manufacturer document: Lycoming MSB No. 566 Supplement No. 1 (Tables 1 and 2) for all applicability determinations","Conditional applicability logic: check engine SN (Table 1) then crankshaft SN (Table 2) if replacement crankshaft was installed (Requirement 1)","Three-part requirement structure with a prohibition, replacement mandate, and inspection steps (Requirement 1–3)","One temporal compliance window repeated across requirements (50 hours TIS or 6 months), plus an immediate installation prohibition (Compliance)","Small number of defined affected engine models (AEIO‑360, IO‑360, O‑360, LIO‑360, LO‑360) so subject population is narrow","Several notes and cross-references including exemptions for crankshafts installed before 1 March 1999 and references to other MSBs/ADs (Note 1, Note 2, Note 3)"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires owners/operators of affected Lycoming piston engines to check engine and crankshaft serial numbers against two tables in Supplement No. 1 to Lycoming Mandatory Service Bulletin (MSB) No. 566 (dated 30 November 2005). (Requirement 1)\n- If your crankshaft serial number appears in Table 2 of that Supplement, you must replace the crankshaft with one whose serial number is not listed in Table 2. (Requirement 2)\n- Prohibits installing any crankshaft whose serial number appears in Table 2 into any engine. (Requirement 3 / Note 3)\n- Sets a compliance deadline: replacement or checks must be done within 50 hours time-in-service or 6 months from the AD’s effective date, whichever comes first; the installation prohibition is effective immediately from the AD’s date. (Compliance)\n\n**Who this affects**\n\n- Owners/operators and maintenance organisations of Lycoming AEIO-360, IO-360, O-360, LIO-360 and LO-360 series piston engines that were manufactured new, rebuilt, overhauled, or had a crankshaft installed after 1 March 1999. (Applicability)\n- Maintenance suppliers and parts vendors who supply or install crankshafts for these engines, because they must not install crankshafts listed in Table 2. (Requirement 3)\n\n**Why it matters (official rationale and testing that claim)**\n\n- The stated reason given by the regulator is to prevent crankshaft failure following an observed crankshaft failure in an LO-360-A1H6 engine; failure could lead to total engine power loss and in-flight engine failure. (Background)\n\nAssessment of that rationale against practical effects, costs and trade-offs:\n\n- Who pays: the aircraft owner/operator bears the direct costs (parts and labour) of replacing a listed crankshaft, plus indirect costs from aircraft down-time. (Requirement 2; Compliance)\n- Who decides and acts: the owner/operator and their maintenance organisation must inspect serial numbers and, if listed, carry out the replacement; the regulator enforces compliance. (Requirement 1–3; Compliance)\n- Compliance burden and implementation risk: the AD depends on accurate serial-number records and on the engine/crankshaft SNs being listed correctly in Lycoming MSB No. 566 Supplement No. 1 (external document). If records are incomplete or MSB tables are ambiguous, operators may face additional diagnostic effort or delay. (Requirement 1; Note 3)\n- Market and supply effects: replacing a crankshaft on potentially many engines concentrates demand for unlisted replacement crankshafts and competent overhaul shops, which can increase parts lead-times and labour costs during the compliance window. This is a practical bottleneck risk, not addressed within the AD text. (Requirement 2; Compliance)\n- Behavioural change: maintenance providers must refuse to install any crankshaft listed in Table 2; owners will likely audit serials of replacement parts before purchase. (Requirement 3)\n- Exceptions and scope limitations: engines whose crankshafts were manufactured, rebuilt, overhauled or replaced by Lycoming prior to 1 March 1999 and not subsequently changed are out of scope — those owners need take no action. (Note 1)\n- Cross-references: the AD requires use of Lycoming MSB No. 566 Supplement No. 1 (Tables 1 and 2) and references FAA AD 2006-06-16. The MSB tables (external to this AD) are essential to determine applicability, which adds a dependency on the manufacturer’s bulletin. (Requirement 1; Note 3)\n\n**Concrete, short summary**\n\n- Check your engine and crankshaft serial numbers against the two tables in Lycoming MSB No. 566 Supplement No. 1. If your crankshaft SN is listed in Table 2, you must replace it with a crankshaft whose SN is not listed, and you may not install crankshafts listed in Table 2 into any engine. Do this within 50 flight hours or 6 months, whichever is sooner. (Requirement 1–3; Compliance)\n\n(References in parentheses indicate the clause or note in the AD that sets out the requirement or exemption.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-115-lycoming-crankshaft-replacement","history":"/api/acts/ad-lyc-115-lycoming-crankshaft-replacement/history","analysis":"/api/acts/ad-lyc-115-lycoming-crankshaft-replacement/analysis","conflicts":"/api/acts/ad-lyc-115-lycoming-crankshaft-replacement/conflicts","importantCases":"/api/acts/ad-lyc-115-lycoming-crankshaft-replacement/important-cases","documents":"/api/acts/ad-lyc-115-lycoming-crankshaft-replacement/documents"}}