AD/PHZL/91 - Hub Blade Socket Lubrication Holes

The Directive is organised around a small set of operational requirements and cross-references to Hartzell service material. The primary technical concept is detection and mitigation of cracking at the hub blade socket lubrication holes by non-destructive inspection, specifically Eddy Current Inspection (ECI), as set out in Hartzell ASB No. HC-ASB-61-297, Revision 1. The AD singles out a defined population of propellers: Hartzell left-hand rotating HC-( )(2,3)Y(K,R)-2 two- and three-bladed aluminium hub “compact” series propellers that have a non-suffix serial number and lubrication holes located on the shoulder of the hub blade socket, when installed on certain Lycoming engines fitted to specified aeroplane models (Applicability).

Mechanically, the Directive imposes four categories of action. First, a diagnostic requirement: perform ECIs in the specified area to check for cracks (Requirement 1). Second, a mandated removal action if the diagnostic reveals cracking: remove the propeller hub from service (Requirement 2). Third, a record/identification duty where no defect is found: mark the propeller in accordance with the ASB (Requirement 3). Fourth, an installation prohibition: do not fit hubs with certain serial number characteristics that were removed from affected propellers (Requirement 4). These actions are time-bound: the Directive prescribes an initial inspection window and repetitive inspection intervals (Compliance).

The Directive also contemplates lifecycle remedies. It permits an optional terminating action to end the repetitive inspections by replacing the subject hub with a hub having an "A" or "B" suffix serial number; the ASB lists replacement part numbers (Optional Terminating Action). The instrument recognises prior compliance: ECIs done before the effective date using the earlier ASB dated 17 September 2007 are accepted as meeting the Directive’s requirements, and later revisions of the SB approved by the FAA as an AMOC to FAA AD 2008-13-28 are acceptable for equivalent requirements of this Directive (Previous Credit).

Technically and procedurally, the AD anchors the operator’s obligations to the Hartzell ASB procedure paragraphs (for example, paragraphs 3.A. through 3.A.(3)(d) for inspection technique and 3.A.(5)(a) for marking), and to FAA AD material for prior compliance and alternative methods of compliance. The safety rationale is explicit: the FAA reported four instances of hub cracking, including two in-flight blade separations, and the AD’s stated intent is to prevent hub failure and consequent blade separation and loss of aircraft control (Background).

The Directive identifies a specific set of propeller models and installation contexts. Applicability is limited to Hartzell Propeller Inc. left-hand rotating HC-( )(2,3)Y(K,R)-2 two- and three-bladed aluminium hub “compact” series propellers that have a non-suffix serial number, and that have lubrication holes located on the shoulder of the hub blade socket, when installed on Lycoming Engines LIO-360 series and LO-360 series reciprocating engines fitted to Piper Aircraft, Inc. Seneca PA-34-200 and Seminole PA-44-180 aeroplanes, and Hawker Beechcraft Corporation Model 76 Duchess aeroplanes (Applicability). The parentheses in the propeller model number are noted in the instrument as indicating optional letters; the AD states it applies regardless of whether those letters are present or absent in the propeller model designation (Applicability Note 1).

The Directive’s requirements therefore apply to any aeroplane in which the specified Hartzell propellers, with the stated hub serial number characteristics and lubrication-hole location, are installed. The instrument does not list individual owners, maintenance organisations, or specific registrants; it frames applicability by propeller model, hub serial number property (non-suffix, or an "E" suffix if removed from affected propellers), engine type, and aircraft model (Applicability; Requirement 4).

Operationally, the Directive imposes obligations on the entity responsible for ensuring airworthiness compliance for the affected propellers. The text requires performance of Eddy Current Inspections in accordance with the Hartzell ASB procedures (Requirement 1), requires removal from service when cracks are found (Requirement 2), and requires marking in accordance with the ASB when no cracks are found (Requirement 3). The text also prohibits installation of specific removed hubs (Requirement 4). The AD accepts prior ECIs done before the effective date using Hartzell ASB dated 17 September 2007 as compliant (Previous Credit), and accepts later SB revisions approved by the FAA as AMOCs for equivalent compliance (Previous Credit).

The Directive references repair/replacement options in Hartzell service material: optional terminating action is replacement of a non-suffix SN hub with a hub carrying an "A" or "B" suffix; replacement part numbers are provided in paragraph 2.A., Material Information, of Hartzell ASB No. HC-ASB-61-297, Revision 1 (Optional Terminating Action). The AD’s effective date is 28 August 2008, so the obligations attach to affected equipment from that date forward (Compliance).

The Directive sets discrete mandatory duties. Duty 1: perform an Eddy Current Inspection of the area around the lubrication holes of the hub blade sockets in accordance with paragraphs 3.A. through 3.A.(3)(d) of Hartzell ASB No. HC-ASB-61-297, Revision 1, dated 14 November 2007 (Requirement 1). Duty 2: if any cracks are found, remove the propeller hub from service (Requirement 2). Duty 3: if no cracks are found, mark the propeller using paragraph 3.A.(5)(a) of the Accomplishment Instructions of Hartzell ASB No. HC-ASB-61-297, Revision 1, to indicate compliance with the ASB (Requirement 3). Duty 4: do not install on any engine in any aircraft propeller hubs that have a non-suffix SN, or an "E" suffix letter in the SN removed from affected propellers in this AD (Requirement 4).

The Directive prescribes compliance timing for those duties. For Requirement 1 (ECI), the initial inspection is required within 50 flight hours after the effective date or within 12 months after the effective date, whichever occurs first, unless previously accomplished; thereafter inspections must be repeated at intervals not to exceed 50 flight hours or 12 months, whichever occurs first (Compliance). For Requirement 2 (removal), removal from service is required before further flight (Compliance for Requirement 2). For Requirement 3 (marking), marking is required at completion of the inspection as detailed in Requirement 1 (Compliance for Requirement 3). For Requirement 4 (installation prohibition), the prohibition applies from the effective date of the AD (Compliance for Requirement 4). The AD becomes effective on 28 August 2008.

Rights or optional actions recognised by the Directive include an Optional Terminating Action: replacing the non-suffix serial-numbered propeller hub with a propeller hub identified by an "A" or "B" suffix letter in the propeller hub serial number will terminate the repetitive ECI requirement for that hub (Optional Terminating Action). The AD directs the user to Hartzell ASB paragraph 2.A., Material Information, for replacement propeller hub part numbers.

The Directive also recognises prior compliance as meeting its requirements: ECIs performed before the AD’s effective date using Hartzell ASB No. HC-ASB-61-297, dated 17 September 2007, are credited as complying with the AD (Previous Credit). The Directive further accepts later revisions of the SB, provided they are approved by the FAA as an Alternate Method of Compliance (AMOC) to FAA AD 2008-13-28, for compliance with the equivalent requirements of this Directive (Previous Credit).

Procedurally, the Directive anchors technical execution to specific paragraphs of the Hartzell ASB (for example, inspection paragraphs 3.A. through 3.A.(3)(d) and marking paragraph 3.A.(5)(a)), thereby delegating method specification to the manufacturer's Alert Service Bulletin while making the obligation mandatory in regulatory terms (Requirements).

The text provided is an Airworthiness Directive issued by the Civil Aviation Safety Authority and includes the formal signature block (James Coyne, Delegate of the Civil Aviation Safety Authority, 16 July 2008) and an effective date (28 August 2008). The instrument itself specifies mandatory actions and timing but does not set out penalty provisions within the text provided. The Directive prescribes required inspections, removal from service when cracks are found, marking after inspection, and a prohibition on installation of specified hubs removed from affected propellers (Requirements and Compliance). It also provides an optional terminating action and credit for prior ECIs performed under the earlier ASB (Optional Terminating Action; Previous Credit).

Enforcement mechanisms such as penalties, sanctions, or administrative processes are not detailed in the text supplied. The Directive does, however, frame the actions as obligations by setting precise compliance windows and conditions: initial inspection within 50 flight hours or 12 months, whichever occurs first, with repetitive intervals not to exceed 50 flight hours or 12 months thereafter (Compliance). The AD further requires removal from service before further flight if cracks are found (Compliance for Requirement 2). These timing requirements establish clear non-compliance criteria in operational terms.

The instrument references FAA AD 2008-13-28 and indicates that ECIs carried out before the effective date using Hartzell ASB dated 17 September 2007 comply with this AD; it also states that later revisions of the SB approved by the FAA as an AMOC to FAA AD 2008-13-28 are considered acceptable for compliance with equivalent requirements of this Directive (Previous Credit). The Directive thereby identifies acceptable alternative compliance documentation but does not, within the supplied text, set out penalties or enforcement procedures for failure to comply. The absence of penalty language in the document supplied means that any statement about sanctions or enforcement practice beyond the AD’s mandatory requirements would be outside the text provided.

The Directive explicitly cross-references related United States regulatory material and Hartzell service documents as part of its compliance framework. It cites FAA AD 2008-13-28 Amdt 39-15591 dated 19 June 2008 in a note and states that later revisions of the Hartzell service bulletin (SB), if approved by the United States Federal Aviation Administration as an Alternate Method of Compliance (AMOC) to FAA AD 2008-13-28, are acceptable for compliance with the equivalent requirements of this Directive (Previous Credit). That establishes an explicit acceptance mechanism for FAA-approved AMOCs to satisfy equivalent elements of this AD.

The Directive incorporates Hartzell Propeller Inc. Alert Service Bulletin No. HC-ASB-61-297, Revision 1, dated 14 November 2007, by reference for the inspection procedure (paragraphs 3.A. through 3.A.(3)(d)) and for the marking requirement (paragraph 3.A.(5)(a)) (Requirement 1; Requirement 3). It also points users to paragraph 2.A., Material Information, of that ASB for replacement propeller hub part numbers when performing the optional terminating action (Optional Terminating Action). The AD accepts earlier Hartzell ASB No. HC-ASB-61-297 dated 17 September 2007 for prior ECIs done before the effective date as compliant with this Directive (Previous Credit).

Those cross-references mean that compliance with the Hartzell ASB and with FAA-approved AMOCs is explicitly integrated into the compliance regime of this Directive. The AD thereby creates a compliance path that recognises certain external approvals and documents. The text supplied does not refer to other Australian statutory instruments or to international conventions beyond the FAA material and the Hartzell ASB. It also does not provide a general hierarchy or conflict-resolution clause; rather it specifies particular alternate-compliance recognition: FAA-approved AMOCs to FAA AD 2008-13-28 are acceptable for equivalent requirements of this Directive (Previous Credit).

The Directive’s prohibition on installing propeller hubs removed from affected propellers on any engine in any aircraft (Requirement 4) interacts with maintenance and parts-tracking practices required by operators and maintenance organisations, insofar as it restricts re-use of specified parts. The AD also provides for an optional terminating action via replacement with hubs having particular suffixes, with replacement part numbers referenced in the Hartzell ASB (Optional Terminating Action). The AD’s compliance windows and repetitive inspection intervals set regulatory timelines that will interact with maintenance scheduling, airworthiness records, and any other statutory inspections or checks required under other instruments; however, the supplied text does not identify or reconcile those other instruments explicitly aside from the Hartzell and FAA materials cited.

The Directive references specific revisions of Hartzell Propeller Inc. Alert Service Bulletin No. HC-ASB-61-297 and acknowledges the earlier Hartzell SB dated 17 September 2007. The AD itself requires compliance with Hartzell ASB No. HC-ASB-61-297, Revision 1, dated 14 November 2007 (Requirement 1; Requirement 3). It grants credit for ECIs performed before the AD’s effective date using Hartzell ASB No. HC-ASB-61-297 dated 17 September 2007 (Previous Credit). The AD also recognises that later revisions of the SB will be acceptable if such later revisions are approved by the FAA as an Alternate Method of Compliance to FAA AD 2008-13-28 (Previous Credit).

The AD cites FAA AD 2008-13-28 Amdt 39-15591 dated 19 June 2008 in a note, indicating linkage between the Australian Directive and the FAA AD (Previous Credit; Note 2). The Directive itself was signed on 16 July 2008 and is stated as becoming effective on 28 August 2008 (signature block and Compliance information).

Beyond these references, the supplied text does not contain any subsequent amendments, revocations, or replacement versions of AD/PHZL/91. The instrument sets an effective date and incorporates a particular revision of the Hartzell ASB as the operative service instruction. It allows for later SB revisions to be accepted if they carry FAA AMOC approval for the FAA AD cited. The supplied text therefore establishes a temporal chain: original Hartzell SB (17 September 2007) is credited for prior ECIs; Revision 1 (14 November 2007) is the operative ASB referenced for inspections and marking; FAA AD 2008-13-28 (19 June 2008) is cited as related FAA regulatory action; AD/PHZL/91 is signed 16 July 2008 and becomes effective 28 August 2008. No further amendment history appears in the text provided.

The text provided contains no record of litigation, judicial review, or legal proceedings relating to this Directive. It sets out regulatory obligations, cross-references to Hartzell Propeller Inc. Alert Service Bulletin No. HC-ASB-61-297 (Revision 1) and to FAA AD 2008-13-28, and documents the signature of a CSA Delegate (James Coyne) and the dates of signature and effect (16 July 2008 and 28 August 2008 respectively). It also records factual background supplied by the FAA concerning four reports of propeller hub cracks including two in-flight blade separation events (Background).

Because the document itself does not record any court actions, appeals, or administrative challenges, there is no litigation history in the instrument to summarise. The AD does, however, identify related FAA regulatory material (FAA AD 2008-13-28) and Hartzell service material, which could form the basis for compliance, alternative methods of compliance, or further administrative interactions. Any litigation or disputes arising from enforcement, replacement part supply, manufacturer instructions, or interpretation of the ASB and AD would not appear in the supplied text unless specifically recorded; none is recorded here.

Therefore, the record in the supplied instrument is silent on litigation. Practitioners seeking information about any subsequent legal challenges to this Directive, or disputes arising under it, will need to consult court records, administrative decisions, or updated regulatory publications which are not contained in the text provided.

The Directive contains precise applicability and procedural references that create potential operational pitfalls if they are overlooked. First, applicability is narrowly defined: it applies only to Hartzell left-hand rotating HC-( )(2,3)Y(K,R)-2 two- and three-bladed aluminium hub “compact” series propellers that have a non-suffix serial number and lubrication holes located on the shoulder of the hub blade socket, when installed on specified Lycoming engines and aeroplane types (Applicability). The AD expressly states it applies regardless of whether optional letters in the propeller model designation are present (Applicability Note 1). Failure to confirm the specific model variant, hub serial number format (non-suffix, or "E" suffix in the context of removed hubs), and lubrication-hole location could lead to mistaken non-compliance or unnecessary action.

Second, the inspection procedure is not fully contained within the AD text; the AD mandates ECIs “in accordance with” specified paragraphs of Hartzell ASB No. HC-ASB-61-297, Revision 1 (Requirement 1). Practitioners must follow paragraphs 3.A. through 3.A.(3)(d) of that ASB for the method and extent of inspection. Likewise, the marking duty references paragraph 3.A.(5)(a) of the ASB (Requirement 3). Not consulting the referenced ASB paragraphs, or following a different inspection technique, will not meet the AD’s stated method-of-compliance.

Third, timing requirements are precise and conjunctive: the initial inspection window is “within 50 flight hours after the effective date or within 12 months after the effective date, whichever occurs first” and thereafter repeat at “intervals not to exceed 50 flight hours or 12 months, whichever occurs first” (Compliance). Miscounting flight hours or calendar intervals, or applying the intervals from the wrong starting point, could render an inspection late.

Fourth, the Directorate requires removal from service “before further flight” if cracks are found (Requirement 2; Compliance). That imposes an immediate grounding of the propeller hub; any continued flight with a cracked hub would conflict with the Directive’s explicit removal requirement.

Fifth, the AD introduces a parts-use prohibition: “Do not install on any engine in any aircraft propeller hubs that have a non-suffix SN, or an 'E' suffix letter in the SN removed from affected propellers in this AD” (Requirement 4). Hubs removed from affected propellers therefore cannot be lawfully reinstalled on any engine in any aircraft. That prohibition extends beyond the originally affected aeroplanes or engines: the words “on any engine in any aircraft” create a broad ban on reinstalling those removed hubs elsewhere.

Sixth, the AD refers to an Optional Terminating Action , replacing the non-suffix SN hub with an "A" or "B" suffix hub , and directs users to paragraph 2.A. of the ASB for replacement part numbers. Procuring the correct replacement hubs requires attention to the ASB Material Information. There is no replacement-part list in the AD text itself.

Seventh, previous ECIs conducted before the effective date using the earlier Hartzell ASB dated 17 September 2007 are credited as compliant (Previous Credit). However, the AD also states that later SB revisions approved by the FAA as an AMOC to FAA AD 2008-13-28 are acceptable for equivalent compliance (Previous Credit). Users must therefore track not only whether inspections were performed but also which revision of the ASB or SB was used and whether an FAA AMOC applies.

Finally, the safety rationale is recorded as four FAA reports of hub cracks including two in-flight blade separations, and the AD’s stated intent is to prevent hub failure leading to blade separation and loss of aircraft control (Background). That background ties the inspection and removal requirements to a specific hazard; operators must therefore treat the inspection and removal duties as responses to an identified in-service failure mode.

Follow the Directive’s four operative requirements and the compliance timing set out in the instrument, using Hartzell ASB No. HC-ASB-61-297, Revision 1, as the procedure document.

1. Identify applicability precisely. Confirm the propeller is a Hartzell left-hand rotating HC-( )(2,3)Y(K,R)-2 two- or three-bladed aluminium hub “compact” series propeller, that the hub has a non-suffix serial number, and that lubrication holes are located on the shoulder of the hub blade socket. Also confirm the installation context: Lycoming LIO-360 or LO-360 engines installed on Piper Seneca PA-34-200, Piper Seminole PA-44-180, or Hawker Beechcraft Model 76 Duchess (Applicability). The AD states it applies regardless of optional letters in the model designation (Applicability Note 1).

2. Perform the required Eddy Current Inspection. Conduct an ECI of the area around the lubrication holes of the hub blade sockets in accordance with paragraphs 3.A. through 3.A.(3)(d) of Hartzell ASB No. HC-ASB-61-297, Revision 1, dated 14 November 2007 (Requirement 1). The AD requires an initial inspection within 50 flight hours after the effective date (28 August 2008) or within 12 months after that date, whichever occurs first, unless already accomplished; thereafter perform ECIs at intervals not exceeding 50 flight hours or 12 months, whichever occurs first (Compliance for Requirement 1). Ensure logbooks and airworthiness records reflect the inspection and the interval calculations.

3. If cracks are detected, remove the hub from service. The AD requires removal of the propeller hub from service if any cracks are found during the ECI (Requirement 2). The compliance instruction states removal must be effected before further flight (Compliance for Requirement 2). Record the removal action in maintenance records and ensure the hub is not installed on any engine in any aircraft if it was removed from an affected propeller (Requirement 4).

4. If no cracks are found, mark the propeller per the ASB. Where the ECI reveals no cracking, mark the propeller using paragraph 3.A.(5)(a) of the Accomplishment Instructions of Hartzell ASB No. HC-ASB-61-297, Revision 1, to indicate compliance with the ASB (Requirement 3; Compliance for Requirement 3). Keep documentary evidence of the inspection and marking in the relevant maintenance and airworthiness records.

5. Do not reinstall removed hubs. The AD prohibits installation, on any engine in any aircraft, of propeller hubs that have a non-suffix serial number or an "E" suffix letter in the serial number that were removed from affected propellers under this AD (Requirement 4). Track removed parts and ensure they are segregated and not reintroduced into service.

6. Consider the Optional Terminating Action where appropriate. As an optional way to terminate the repetitive ECI requirement for a hub, replace the non-suffix serial-numbered hub with a hub identified by an "A" or "B" suffix letter in the hub serial number (Optional Terminating Action). Replacement propeller hub part numbers are listed in paragraph 2.A., Material Information, of Hartzell ASB No. HC-ASB-61-297, Revision 1. Use the ASB Material Information to select the correct replacement part numbers and document the terminating action.

7. Credit prior inspections where applicable. If an ECI was performed before the AD’s effective date using Hartzell ASB No. HC-ASB-61-297 dated 17 September 2007, the AD states that such inspections comply with the AD (Previous Credit). If you have performed earlier ECIs under that earlier ASB, retain records evidencing the date, method (ASB reference), and results to support this credit.

8. Use FAA-approved AMOCs where authorised. The Directive accepts later revisions of the SB that have been approved by the FAA as an Alternate Method of Compliance to FAA AD 2008-13-28, as acceptable for compliance with the equivalent requirements of this Directive (Previous Credit). If relying on an FAA AMOC, maintain the approval documentation as part of the maintenance record demonstrating compliance with the AD.

9. Maintain records and follow the ASB detail. The AD ties practical steps to specific paragraphs in the Hartzell ASB (for example paragraphs 3.A. through 3.A.(3)(d) for ECI technique and 3.A.(5)(a) for marking). Obtain and follow the full ASB text for procedural detail, measurement thresholds, acceptance criteria, marking specifics, and Material Information (including replacement part numbers).

10. Observe the effective date and timing. The AD becomes effective on 28 August 2008. If ECIs or other actions were carried out before that effective date under the earlier ASB, ensure records show the ASB version used (Previous Credit). For ongoing compliance, calendar and flight-hour tracking must ensure inspections do not exceed the limits of 50 flight hours or 12 months between ECIs, measured from the appropriate starting point identified in Compliance.

The Directive does not provide step-by-step inspection technique detail within its text; compliance therefore requires consulting Hartzell Propeller Inc. Alert Service Bulletin No. HC-ASB-61-297, Revision 1, dated 14 November 2007, for the inspection procedure and marking instructions referenced in the AD. The AD also refers to FAA AD 2008-13-28 for cross-credit and AMOC processes; users relying on FAA AMOCs must retain the relevant FAA approval documentation.