{"id":"F2007L00094","name":"AD/LYC/102 Amdt 3 - Crankshaft Internal Inspection","slug":"ad-lyc-102-amdt-3-crankshaft-internal-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":68153,"registerId":"commonwealth-F2007L00094-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/102 Amdt 3 | Crankshaft Internal Inspection | 2/2007 |\n| ----------------- | ------------------------------ | ------ |\n\n| Applicability: | Lycoming O-320 and O-360 series engines as detailed in Lycoming Mandatory Service Bulletin (MSB) No. 505B; and not incorporating a front bore protective coating as detailed in Lycoming Service Bulletin No. 530 at any revision status.Note 1: Engines applicable are engines fitted with hollow front bore crankshafts and installed in aircraft propelled by fixed pitch propellers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Carry out an internal inspection of the crankshaft front bore for evidence of corrosion in accordance with Lycoming MSB No. 505B or later FAA approved revisions.If there is no evidence of pitting corrosion in the front bore, no further action is required until the next inspection as detailed in the compliance requirements of this Directive.2. If in carrying out the internal inspection in accordance with Requirement 1 of this Directive there is evidence of pitting corrosion in the front bore:a. Carry out a Fluorescent Penetrant Inspection (FPI) in accordance with the FPI procedures detailed in Lycoming MSB No. 505B or later FAA approved revisions.b. Remove any evidence of pitting corrosion in accordance with approved data (procedures approved by CAR 35 authorised persons are considered acceptable for the purpose of this AD) or remove the crankshaft from service.c. If in carrying out the FPI, a crankshaft is found to be cracked, remove the crankshaft from service.3. Spare crankshafts: Carry out an internal inspection of the crankshaft front bore for evidence of corrosion in accordance with MSB No. 505B or later FAA approved revisions; and |\n\n|             | a. Remove any evidence of pitting corrosion in accordance with approved data (procedures approved by CAR 35 authorised persons are considered acceptable for the purpose of this AD); andb. Carry out a Magnetic Particle Inspection of the crankshaft front bore in accordance with approved data; andc. Apply a protective coating in accordance with Lycoming MSB No. 530 dated 1 December 1997 or later FAA approved revisions.Note 2: The application of Urethabond 104 to the inner bore of the crankshaft and confirmed by stamping of the letters \"PID\" on the outside diameter of the propeller flange in accordance with Lycoming MSB No. 530 or later FAA approved revisions constitutes terminating action to the inspection requirements of this AD.Note 3: FAA Airworthiness Directive 98-02-08 amendment 39-10291 refers.                                                                                                                                           |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | Requirement 1:Engines with a time in service (TIS) since new, remanufacture or overhaul, of greater than 1,000 hours or 10 years:within 100 hours TIS or 12 months from effective date of this AD or at next removal of the crankshaft from the engine, whichever occurs first, unless previously accomplished; andrepetitively thereafter at intervals not to exceed 5 calendar years.Engines with a TIS since new, remanufacture or overhaul of less than 1,000 hours and 10 years:prior to exceeding 1,100 hours TIS or 11 years TIS or at next removal of the crankshaft from the engine, whichever occurs first, unless previously accomplished; andrepetitively thereafter at intervals not to exceed 5 calendar years.Requirement 2:a. Before further flight.b. Within 100 hours time in service.c. Before further flight.Requirement 3(a), 3(b) and 3(c):Prior to installation of a crankshaft in an engine, unless previously accomplished.                               |\n|             | This Amendment becomes effective on 15 February 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| Background: | The AD was originally issued to require the inspection of hollow front bore crankshafts fitted with fixed pitch propellers. The requirement addressed CAA (UK) advice of two crankshaft failure events in flight. Crankshaft failure can result in engine failure, propeller separation, forced landing, and possible damage to the aircraft.The current Amendment clarifies compliance requirements at the request of the industry and makes reference to the latest revision(s) of the service documents.The Amendment 2 of this AD was issued to include CAR 35 authorised persons in designing and approving inspection and repair schemes. Amendment 2 became effective on 8 October 1998.The Amendment 1 of this AD addressed the concerns raised by the industry by interpreting the compliance requirements and making necessary changes. Amendment 1 became effective on 18 June 1998.The original issue of this Airworthiness Directive became effective on 14 May 1998. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n4 January 2007","sortOrder":0},{"sectionNumber":"AD/LYC/102 Amdt 3","sectionType":"part","heading":"AD/LYC/102 Amdt 3","content":"## AD/LYC/102 Amdt 3","sortOrder":1},{"sectionNumber":"Crankshaft Internal Inspection","sectionType":"part","heading":"Crankshaft Internal Inspection","content":"## Crankshaft Internal Inspection","sortOrder":2},{"sectionNumber":"2/2007","sectionType":"part","heading":"2/2007","content":"## 2/2007","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"This Amendment clarifies compliance timing, references the latest revisions of Lycoming service documents, and formally recognises CAR 35 authorised persons for approving inspection and repair schemes (Background; Requirement 2). It does not broaden engine applicability beyond hollow front‑bore crankshafts on specified O‑320/O‑360 fixed‑pitch installations but changes who may approve repairs and how compliance timing is read (Background; Compliance)."},"complexity_factors":["Multiple conditional requirements depending on inspection findings (Requirement 1–3)","Different compliance timings tied to time‑in‑service (TIS), age, and crankshaft removal (Compliance)","Multiple inspection techniques required: internal inspection, Fluorescent Penetrant Inspection (FPI), Magnetic Particle Inspection (MPI) (Requirement 2 and 3)","References to external service documents (Lycoming MSB No. 505B, MSB No. 530) and FAA ADs, creating dependency on later approved revisions (Requirement text; Notes)","Acceptance of repair procedures approved by CAR 35 authorised persons increases reliance on delegated approval (Requirement 2; Background)","Separate treatment and additional steps for spare crankshafts, including terminating action via protective coating and identification stamping (Requirement 3; Note 2)","Immediate actions required in some cases (e.g. before further flight) increase operational urgency and potential grounding costs (Requirement 2 compliance timing)","Enforcement and interpretation risk from cross‑referenced external documents and later revisions"],"plain_english_summary":"Requires internal inspection of hollow front‑bore crankshafts on specified Lycoming O‑320/O‑360 engines for front‑bore corrosion, with mandated fluorescent‑penetrant or magnetic‑particle inspections, removal or approved repair, and optional protective coating as terminating action (Requirement 1–3; Notes). Aircraft owners/operators pay for inspections, repairs and coatings; CAR 35 authorised persons may approve repair procedures (Requirement 2). Inspections recur on time‑in‑service or age thresholds or at crankshaft removal (Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original AD (May 1998) was a straightforward safety response to two in-flight crankshaft failures. Over three amendments, the scope expanded significantly: Amendment 1 (June 1998) added interpretive clarifications for industry concerns; Amendment 2 (October 1998) expanded approval authority to CAR 35 authorised persons (delegating regulatory power to private certifiers); and Amendment 3 (February 2007) added comprehensive spare crankshaft requirements, terminating actions, and complex dual-variable compliance timelines. The directive evolved from a simple inspection mandate to a detailed maintenance management system covering new parts, used parts, repairs, and permanent modifications."},"complexity_factors":["Multiple nested conditional requirements (Requirements 1, 2a/2b/2c, and 3a/3b/3c with branching logic)","Cross-references to external documents (Lycoming MSB No. 505B, MSB No. 530, FAA AD 98-02-08) without reproducing their content","Dual compliance timelines based on two variables (flight hours AND calendar years) creating four possible compliance paths","Technical aviation terminology requiring specialised knowledge (TIS — Time In Service, FPI — Fluorescent Penetrant Inspection, CAR 35 authorised persons)","Exception to the main rule (Note 2 terminating action) that modifies the ongoing obligation","Applicability exclusions based on physical characteristics (front bore protective coating) and equipment type (fixed pitch propellers)"],"plain_english_summary":"This CASA Airworthiness Directive mandates internal inspections of hollow-front-bore crankshafts on Lycoming O‑320 and O‑360 engines with fixed‑pitch propellers, and inspection/conditioning before installing spares. It requires removal or replacement if corrosion or cracking is found, with Magnetic Particle Inspection for cracks. The rule targets operators and maintainers to prevent in‑flight crankshaft failures (two recent breakups) and allows permanent relief only after applying the specified protective coating and markings."}},"importantCases":[],"_links":{"self":"/api/acts/ad-lyc-102-amdt-3-crankshaft-internal-inspection","history":"/api/acts/ad-lyc-102-amdt-3-crankshaft-internal-inspection/history","analysis":"/api/acts/ad-lyc-102-amdt-3-crankshaft-internal-inspection/analysis","conflicts":"/api/acts/ad-lyc-102-amdt-3-crankshaft-internal-inspection/conflicts","importantCases":"/api/acts/ad-lyc-102-amdt-3-crankshaft-internal-inspection/important-cases","documents":"/api/acts/ad-lyc-102-amdt-3-crankshaft-internal-inspection/documents"}}