AD/LYC/102 Amdt 3 - Crankshaft Internal Inspection

The AD is structured around three main conceptual pillars: applicability, detection/mitigation actions, and compliance timing.

Applicability: The AD applies to a defined subset of Lycoming engines: O-320 and O-360 series with hollow front-bore crankshafts installed in aircraft with fixed-pitch propellers, and specifically those engines that do not have the front-bore protective coating described in Lycoming SB No. 530 (Applicability). This narrows scope to a mechanical configuration (hollow front bore) plus a lack of a particular protective modification.

Detection and escalation cascade: The inspection regime is layered. The initial required action is an internal visual inspection of the front bore in accordance with Lycoming MSB No. 505B or later FAA-approved revisions (Requirement 1). If no pitting corrosion is evident, the AD requires repeat inspections at specified intervals. If pitting corrosion is evident, the AD escalates to FPI (Requirement 2(a)), then to corrective action or removal from service if pitting cannot be removed using approved data (Requirement 2(b)), and mandates removal from service if cracking is found by FPI (Requirement 2(c)). For spare crankshafts, the cascade is more prescriptive: inspection, removal of pitting per approved data, MPI of the front bore, and application of protective coating (Requirement 3(a)-(c)).

Approved data and terminating action: The AD ties corrective methods to “approved data”, and explicitly accepts procedures approved by CAR 35 authorised persons as meeting that standard (Requirement 2(b); Background). It designates a specific terminating action: application of Urethabond 104 to the inner bore and stamping “PID” on the propeller flange in accordance with MSB No. 530 constitutes terminating action to the inspection requirements (Note 2). This creates a clear pathway to remove an engine from the ongoing inspection cycle for this AD.

Timing and repetition: The compliance framework uses time-in-service and calendar age thresholds to determine initial inspection timing, and then uniform five-year repetitive intervals thereafter (Compliance). Specific immediate-response timings apply where pitting or cracking is detected (e.g., before further flight, within 100 hours TIS, depending on the requirement).

Cross-reference and provenance: The AD directs operators to Lycoming MSB No. 505B and SB No. 530, but qualifies both by adding “or later FAA approved revisions” to each reference, which allows later FAA-approved revisions of those service documents to be used (Requirements and Notes). The AD also calls out FAA AD 98-02-08 as a related instrument (Note 3).

Collectively, the AD translates manufacturer service instructions and inspection technologies into mandatory regulatory requirements for identified engines and spares, sets objective terminating actions, and frames inspection recurrence using both hours and calendar age metrics.

Directly affected parties: Owners and operators of aircraft powered by Lycoming O-320 and O-360 series engines that have hollow front-bore crankshafts and are fitted with fixed-pitch propellers, and that do not have the front-bore protective coating per Lycoming SB No. 530, fall within the AD’s applicability (Applicability). That includes aircraft owners who possess engines in-service and entities that install spare crankshafts.

Maintenance and repair providers: Maintenance organisations, approved maintenance engineers, and CAR 35 authorised persons who perform inspections, FPI, MPI and repair work on the specified crankshafts are affected because the AD requires work to be carried out in accordance with Lycoming MSB No. 505B (Requirement 1) and accepts CAR 35 authorised persons’ approvals as meeting the “approved data” condition for removal of pitting and for designing inspection and repair schemes (Requirement 2(b); Background). For spare crankshafts, the AD explicitly requires MPI and protective coating application prior to installation, which binds whoever installs spares.

Manufacturers and parts suppliers: Lycoming and suppliers of protective coatings are implicated insofar as the AD references Lycoming MSB No. 505B and MSB No. 530 and names Urethabond 104 as the protective coating whose application and the subsequent “PID” stamping constitutes terminating action (Note 2). Suppliers of inspection services and non-destructive testing (NDT) such as FPI and MPI providers will be engaged for compliance.

Regulator and delegated personnel: The instrument is issued by the Civil Aviation Safety Authority, signed by a Delegate (signature present and dated), and it accommodates approvals by CAR 35 authorised persons (Background). That signals a role for regulator-delegated approvals and oversight in scheme design and approval of repair methods.

Owners of spare crankshafts and maintenance stock-holders: The AD imposes work on spares prior to installation , spares must have the inspection, any pitting removed per approved data, MPI conducted, and protective coating applied per MSB No. 530 before being installed (Requirement 3). This affects inventory management decisions for spares and the handling of second-hand or remanufactured crankshafts.

Downstream stakeholders: Aircraft insurers, operators with fleet-management obligations, and continuing airworthiness managers will be affected indirectly because the AD prescribes inspections and corrective action that bear on airworthiness records, maintenance scheduling, and potential grounding periods while inspections and repairs occur. The AD’s terminating stamp “PID” provides a physical evidence mechanism that those stakeholders can rely on for document control and verification.

Who is not affected: Engines that incorporate the protective coating described in Lycoming SB No. 530, as well as engines outside the O-320 and O-360 series or those without hollow front bores, are excluded by the Applicability clause. Likewise, engines fitted with constant-speed propellers or other propeller systems not mentioned are outside the AD’s defined scope.

Duties imposed by the AD are prescriptive and technical. The AD requires the following primary duties.

Inspection duty: Perform an internal inspection of the crankshaft front bore for evidence of corrosion in accordance with Lycoming MSB No. 505B or later FAA-approved revisions (Requirement 1). This is the foundational obligation from which other duties flow.

Escalation duty on pitting detection: If pitting corrosion is found during the internal inspection, the AD requires:

• Conduct a Fluorescent Penetrant Inspection (FPI) per MSB No. 505B (Requirement 2(a));
• Remove any evidence of pitting corrosion in accordance with approved data, or remove the crankshaft from service (Requirement 2(b)); and
• If the FPI reveals a crack, remove the crankshaft from service (Requirement 2(c)).

Spare-crankshaft duties: For spare crankshafts the AD requires internal inspection, removal of any pitting per approved data, a Magnetic Particle Inspection (MPI) of the crankshaft front bore, and application of protective coating per Lycoming MSB No. 530 before installation (Requirement 3(a)-(c)).

Timing duties: The AD sets concrete inspection timing tied to engine TIS and calendar age (Compliance). Operators must calculate the applicable thresholds (e.g., greater than 1,000 hours or 10 years, versus less than those thresholds) and act within the specified windows, or at next removal of the crankshaft, whichever occurs first. Thereafter, repeat inspections not exceeding five calendar years.

Use of approved data and delegated approvals: The AD conditions removal of pitting and design of inspection and repair schemes on “approved data”. It explicitly accepts procedures approved by CAR 35 authorised persons as constituting approved data for the purpose of this AD (Requirement 2(b); Background). This assigns a delegated approval role to CAR 35 authorised persons and gives operators a pathway to use approved but non-manufacturer repair schemes, provided CAR 35 sign-off exists.

Terminating action right: The AD grants an explicit terminating route for the inspection requirement. The application of Urethabond 104 to the inner bore of the crankshaft and confirmation by stamping “PID” on the outside diameter of the propeller flange, in accordance with MSB No. 530 or later FAA-approved revisions, constitutes terminating action to the inspection requirements of the AD (Note 2). This creates a durable right to remove the crankshaft from the recurring inspection cycle once the specified modification and marking are completed.

Conditional removal rights: The AD permits removal of the crankshaft from service as an option where pitting cannot be removed per approved data, or where cracking is found by FPI (Requirement 2(b)-(c)). That is an operational decision point: remove and replace the crankshaft, or undertake approved repair action.

Documentary and physical evidence duties: While the AD does not state specific record-keeping obligations, it prescribes stamping “PID” as physical evidence for terminating action (Note 2), and refers to MSB documents as the standard for inspection procedures. These create de facto duties to follow MSB procedures and to apply the specified physical marking where terminating action is taken.

Limits and boundaries: The AD’s duties are limited to engines and spares falling under its applicability, and to actions specified in the Requirements. The AD’s references to “later FAA approved revisions” permit operators to rely on updated MSB revisions provided those revisions are FAA-approved.

The AD text itself does not set out criminal, civil or administrative penalties, nor does it specify the enforcement mechanism or sanctions for non-compliance. The document records its effective date, 15 February 2007, and is signed by a CASA Delegate, which establishes its formal issuance (effective date and signature). Beyond that, the text is silent on penalty provisions.

The AD does, however, embed objective compliance markers that facilitate regulatory verification and practical enforcement activity. For example:

• The AD requires inspections and specific NDT techniques (FPI, MPI) and corrective actions to be undertaken in accordance with Lycoming MSB No. 505B and MSB No. 530 or later FAA-approved revisions (Requirement 1; Requirement 3). Compliance can be checked by examining maintenance records that reference those MSB procedures and by inspecting the work done.
• The AD designates a terminating action (application of Urethabond 104 to the inner bore and stamping “PID” on the propeller flange) that creates a clear physical marker that an engine or crankshaft has satisfied the terminating condition (Note 2). That stamping is verifiable on the part itself.
• The AD accepts CAR 35 authorised persons’ approvals as approved data for repair schemes (Requirement 2(b); Background), thereby vesting authorised persons with an administrative role whose approvals are themselves verifiable.

Given the AD’s silence on formal penalties, practical enforcement would, in normal regulatory practice, rely on the issuing authority’s standard oversight and certification frameworks to check compliance records, physical marks, and maintenance actions. The AD does place objective inspection, NDT, and marking requirements into the maintenance regime which creates audit points for any regulator or compliance reviewer.

The AD references FAA Airworthiness Directive 98-02-08 (Note 3), which may be used to align action histories with international directives, but the AD itself does not describe cross-border enforcement mechanics.

Because the instrument does not specify penalties, auditors and advisers should treat the AD’s technical prescriptions as mandatory airworthiness obligations according to its issuance, and rely on physical and documentary markers (MSB compliance references, FPI/MPI reports, “PID” stamps) to demonstrate compliance. Any formal sanctioning or enforcement process is not described within the AD text and would need to be located in the broader statutory or regulatory framework that sits outside this document.

The AD explicitly references and incorporates other regulatory and manufacturer instruments, thereby creating an interaction network rather than operating in isolation.

Incorporation of Lycoming service documents: The AD makes compliance contingent on Lycoming Mandatory Service Bulletin No. 505B and Lycoming Service Bulletin No. 530, or later FAA-approved revisions of those documents (Requirement 1; Requirement 3; Note 2). That means the AD imports substantive inspection and repair procedures from manufacturer-issued service bulletins, but only to the extent those actions are contained in MSB No. 505B/SB No. 530 or their FAA-approved successors.

CAR 35 authorised persons: The AD expressly accepts procedures approved by CAR 35 authorised persons as “approved data” for removal of pitting corrosion and for designing inspection and repair schemes (Requirement 2(b); Background). This creates an explicit interface with CAR 35 approvals and recognises delegated approval authority within the Australian regulatory regime.

Reference to FAA AD: The AD cites FAA Airworthiness Directive 98-02-08 amendment 39-10291 (Note 3). That is a cross-reference to an overseas regulator’s directive, implying alignment or mutual recognition of the safety concern and corrective actions. The AD also permits the use of later FAA-approved revisions of the referenced MSBs.

Effect on manufacturer-recommended maintenance regimes: Because the AD mandates that internal inspections and corrective actions be done “in accordance with Lycoming MSB No. 505B or later FAA approved revisions” and SB No. 530 for protective coating, the AD effectively converts manufacturer-recommended practices (service bulletins) into regulatory obligations. That transforms voluntary manufacturer guidance into mandatory continuing airworthiness tasks for applicable engines and spares.

Interaction with approval processes and maintenance approvals: By referencing CAR 35 authorised persons as acceptable approvers of repair schemes and removal of pitting, the AD interacts with the approval processes under the broader airworthiness regulatory regime. That interaction means that maintenance providers can rely on CAR 35 approval in lieu of other forms of “approved data” for the specific actions covered by the AD.

Gaps in statutory detail: The AD does not identify penalties, record-keeping requirements, or the full enforcement apparatus. Those omissions mean that the AD must be read alongside the broader statutory instruments and regulations that govern aircraft continuing airworthiness and enforcement action in the relevant jurisdiction, although those instruments are not mentioned in the AD text itself.

In sum, the AD operates by importing and mandating specific manufacturer procedures and by recognising certain delegated approvals (CAR 35 authorised persons), while also pointing to an FAA AD for related guidance. It therefore functions as a node in a regulatory and technical network rather than as a standalone, fully self-contained legal instrument.

The AD text provides a concise amendment history that identifies the sequence of prior versions and the purpose of the latest amendment.

Original issue: The original Airworthiness Directive was issued to require inspection of hollow front-bore crankshafts fitted with fixed-pitch propellers. The original issue became effective on 14 May 1998 (Background).

Amendment 1: Amendment 1 was issued to address industry concerns by interpreting the compliance requirements and making necessary changes. Amendment 1 became effective on 18 June 1998 (Background).

Amendment 2: Amendment 2 was issued to include CAR 35 authorised persons in the list of persons capable of designing and approving inspection and repair schemes. Amendment 2 became effective on 8 October 1998 (Background). The AD’s current text repeats that procedures approved by CAR 35 authorised persons are considered acceptable as “approved data” for the purposes of the AD (Requirement 2(b); Background).

Amendment 3 (current): The current Amendment clarifies compliance requirements at the request of industry and makes reference to the latest revision(s) of the service documents. This Amendment (Amendment 3) became effective on 15 February 2007 (Compliance; effective date and signature). The AD’s Compliance paragraph and Requirements reflect those clarifications: specified timing windows keyed to TIS and calendar age, repetitive five-year intervals, and the explicit acceptance of later FAA-approved revisions for the referenced MSBs.

Notes and cross-references: The AD notes that FAA Airworthiness Directive 98-02-08 amendment 39-10291 refers (Note 3), which connects this AD to the FAA’s prior requirement history. The AD’s Note 2 establishes that application of Urethabond 104 and stamping “PID” per MSB No. 530 constitutes terminating action; this is presented as a settled element of the AD in the current amendment.

The amendment history shows iterative refinement: initial issuance to address a safety event cluster, then industry-driven clarification, then extension of approval pathways to CAR 35 authorised persons, and finally a clarifying amendment that aligns compliance language with the latest service document revisions and industry concerns. The text documents the dates of effectiveness for the original issue and subsequent amendments.

The AD text contains no information about litigation, judicial review, or court challenges relating to this directive. It refers only to the AD issuance history and clarifications requested by industry, but it does not identify any court cases, tribunal decisions, or administrative appeals in relation to the AD.

Where a practitioner seeks litigation or dispute records related to this AD, those records are not contained in the AD itself and would need to be sought in external sources such as court databases, tribunal records, or regulatory appeal filings. The AD does reference an FAA AD (note of related foreign-direction), but provides no detail about any disputes or litigation arising from that FAA AD either.

Therefore, the AD is silent on litigation history: there is no mention within the AD text of any contested enforcement action, appeals, or judicial determinations that interpret, stay, or nullify its requirements.

Several practical traps and implementation frictions are implicit in the AD text and deserve attention.

Limited applicability window and “whichever occurs first”: The Compliance provisions use both hours and calendar thresholds (greater than 1,000 hours or 10 years; less than those thresholds but before exceeding 1,100 hours or 11 years) and include the clause “or at next removal of the crankshaft from the engine, whichever occurs first” (Compliance). Operators who schedule crankshaft removals frequently may find that the “next removal” clause accelerates compliance obligations, so care is required in interpreting which event triggers inspection first. The AD’s language places the onus on operators to determine which of the events applies.

Definition of “approved data”: The AD repeatedly requires corrective work “in accordance with approved data” and then clarifies that procedures approved by CAR 35 authorised persons are considered acceptable (Requirement 2(b); Background). However, the AD does not itemise what else counts as approved data. Practitioners should be cautious: absent a CAR 35 approval, the AD does not specify whether only manufacturer or FAA approvals suffice. The AD’s acceptance of CAR 35 approvals does not exclude other forms of approval, but it does not expressly list them either.

Terminating action limited to specified coating and marking: Note 2 identifies the application of Urethabond 104 and stamping of “PID” as terminating action. That is a narrow, material-specific terminating route. Operators who use different protective compounds or alternative marking conventions will not be able to rely on the AD’s terminating-action clause unless their alternative is incorporated via a later FAA-approved revision of SB No. 530 that the AD accepts.

Treatment of spare crankshafts: For spares, the AD requires MPI and protective coating application prior to installation (Requirement 3). That imposes a pre-installation work flow on spares inventories. Operators who routinely install spare crankshafts without prior MPI or coating may face unexpected delays and costs.

Immediate-response requirements: The AD sets stringent immediate-response timings for certain outcomes: Requirement 2(a) says “Before further flight” where pitting is found; Requirement 2(b) specifies within 100 hours TIS for some corrective actions; Requirement 2(c) says “Before further flight” if cracked by FPI. Those timings create operational risk because finding pitting or cracking during scheduled maintenance may necessitate immediate grounding or removal from service of the engine or aircraft.

Record evidence is limited to marking: The AD specifies stamping “PID” as confirmation of terminating action (Note 2), which is a physical marker. The AD does not itself require a particular written entry or log format. Maintenance record-keeping expectations thus rely on standard maintenance practice outside the AD text; if practitioners rely solely on paperwork without the physical mark, they may not meet the AD’s specified terminating evidence.

Cross-jurisdictional reference: The AD allows use of “later FAA approved revisions” of the MSBs. Operators must ensure that any later revision they rely on is indeed FAA-approved and that the revision content is applicable to the specific engine model and configuration. Confusion may arise if multiple revision tracks exist or if a revision is manufacturer-issued but not FAA-approved.

Ambiguity around “remove any evidence of pitting”: The AD requires removal of pitting “in accordance with approved data” or removal from service (Requirement 2(b)). The threshold for what constitutes “removable” pitting versus crankshaft replacement is left to the approved data. Practitioners should not assume that any pitting can be ground out; the approved data may impose limits or conditions.

No penalties in the AD text: Because the AD does not state enforcement or penalty mechanisms, operators might mistakenly rely on an assumption of leniency. The AD nonetheless imposes mandatory requirements; the absence of penalty language in the AD itself is not equivalent to absence of enforcement in the broader regulatory framework.

Compliance requires turning the AD’s text into an operational checklist that ties applicability, inspection, escalation, repair, and marking into maintenance workflows.

1. Verify applicability

   • Confirm engine model and crankshaft configuration: ensure the engine is a Lycoming O-320 or O-360 series with a hollow front-bore crankshaft and is fitted with a fixed-pitch propeller (Applicability).
   • Confirm whether the crankshaft already incorporates the protective coating described in Lycoming SB No. 530. If it does, the AD’s applicability excludes that engine.

2. Identify the relevant MSB revisions

   • Obtain Lycoming MSB No. 505B and Lycoming SB No. 530 and check for any later FAA-approved revisions; the AD allows reliance on later FAA-approved revisions of those documents (requirement language and notes).

3. Schedule inspections according to TIS and calendar age

   • If the engine has TIS since new, remanufacture, or overhaul greater than 1,000 hours or age greater than 10 years, schedule the internal inspection within 100 hours TIS or 12 months from the AD effective date, or at the next removal of the crankshaft from the engine, whichever occurs first. Thereafter, schedule inspections at intervals not exceeding five calendar years (Compliance).
   • If the engine has TIS since new, remanufacture, or overhaul less than 1,000 hours and less than 10 years, schedule the internal inspection before exceeding 1,100 hours TIS or 11 years TIS, or at the next removal of the crankshaft from the engine, whichever occurs first. Repeat every five years thereafter (Compliance).

4. Perform required inspections

   • Conduct the internal inspection of the crankshaft front bore for corrosion in accordance with Lycoming MSB No. 505B or later FAA-approved revisions (Requirement 1).
   • For spare crankshafts, perform the internal inspection prior to installation (Requirement 3).

5. Escalate on detection of pitting

   • If pitting corrosion is evident, perform an FPI in accordance with the FPI procedures in MSB No. 505B or later FAA-approved revisions (Requirement 2(a)).
   • Follow FPI results: if FPI shows cracking, remove the crankshaft from service (Requirement 2(c)). If FPI shows pitting but no crack, remove pitting “in accordance with approved data” or remove the crankshaft from service (Requirement 2(b)). For repairs or alternative procedures, obtain approval from CAR 35 authorised persons if applicable, since the AD accepts such approvals as approved data (Requirement 2(b); Background).

6. Spare crankshaft preparatory steps

   • For spares, after inspection and any pitting removal per approved data, conduct a Magnetic Particle Inspection (MPI) of the front bore in accordance with approved data (Requirement 3(b)).
   • Apply the protective coating per Lycoming SB No. 530 dated 1 December 1997 or later FAA-approved revisions (Requirement 3(c)).

7. Implement terminating action where desirable

   • To terminate the inspection requirement for a crankshaft, apply Urethabond 104 to the inner bore and confirm by stamping the letters “PID” on the outside diameter of the propeller flange, in accordance with MSB No. 530 or later FAA-approved revisions (Note 2). Ensure the stamping matches the AD’s specified marking.

8. Use CAR 35 authorised persons where needed

   • Where a repair or inspection scheme departs from the manufacturer’s MSB but is intended to meet the AD’s requirement, have the scheme approved by a CAR 35 authorised person, noting that such approvals are explicitly accepted as “approved data” by this AD (Requirement 2(b); Background).

9. Evidence and records

   • Maintain FPI and MPI reports, repair approvals, and any documentation associated with MSB compliance and CAR 35 authorised person approvals. Retain evidence of the “PID” stamping where terminating action is taken. The AD does not prescribe record formats; use standard maintenance record practices to create an auditable trail.

10. Operational response

    • Where the AD requires action “before further flight” (Requirement 2(a); Requirement 2(c)), plan for immediate grounding and removal/repair as necessary. Where time windows allow “within 100 hours TIS” plan maintenance scheduling accordingly to avoid non-compliance.

11. Review for updates

    • Because the AD allows use of MSB or SB later FAA-approved revisions, periodically check for FAA-approved revisions to MSB No. 505B and SB No. 530 that could alter inspection techniques, acceptable materials, or other procedures, and apply the later FAA-approved revision where relevant.

12. Spare inventory management

    • For organisations that stock spare crankshafts, ensure spares are inspected, MPI-tested, treated with protective coating, and stamped “PID” where terminating action is applied prior to installation, to avoid last-minute work when fitting a spare.

Following these steps will align maintenance practice with the AD’s requirements as stated in the document: inspection per MSB No. 505B, escalation to FPI/MPI, corrective actions via approved data (including CAR 35 approvals), and use of Urethabond 104 and “PID” stamping as terminating action (Requirements; Note 2; Compliance).