AD/PHZL/64 Amdt 2 - Hub Pilot Tube Bore

The AD relies on a small set of technical and regulatory concepts that determine scope, trigger events, and the corrective pathway.

• Applicability and model designation: The AD applies to all Hartzell propellers with model designation HC-B4TN-5(D,G,J)L/LT10282(N)(B,K)-5.3R fitted to Mitsubishi MU-2B-26A, MU-2B-36A, MU-2B-40, or MU-2B-60 aircraft, and to any other MU-2 series aircraft modified by installation of the subject propeller. The AD states that parentheses in the model designation indicate optional letters that may be present or absent and that the absence/presence of those letters does not change applicability. This means the AD is attached to the underlying hub/blade family rather than specific suffix permutations.

• Requirement Documents: The AD invokes Hartzell Alert SB A182A or A183A "as applicable" for hub inspections and Hartzell Alert SB A188. The text refers to these documents as the Requirement Documents that specify inspection and related actions. The AD therefore delegates technical inspection procedures to the manufacturer’s service bulletins and makes compliance conditional on following those documents.

• Inspection triggers and intervals: The AD prescribes inspection triggers based on hub or blade hours time in service (TIS) as of a specific date (24 February 1995), and sets recurrent intervals. For hubs, initial triggers are: immediate inspection within 10 TIS or by 30 April 1995 for hubs ≥3000 hours or unknown; or before reaching 3010 hours or within 200 hours from 24 February 1995 for hubs <3000 hours. Reinspection intervals are 600 hours TIS or 5 years until the terminating part is fitted, then 3000 hours TIS thereafter. For blades, inspection timing is governed by bands: blades ≥2900 hours inspected within 100 hours; blades 2201-2900 inspected before reaching 3000 hours; blades ≤2200 inspected within 800 hours. Reinspection thereafter at each overhaul or every 3000 hours TIS.

• Terminating action and specific parts: The AD identifies a specific hub assembly and pilot tube parts, hub P/N 840-139 with pilot tubes P/N A1891A, described as "compressively rolled internal pilot tube bores". Fitting that hub assembly changes the reinspection interval from 600 hours/5 years to 3000 hours. The AD treats fitting that part as terminating for the more frequent inspection requirement.

• Blade strike definition: The AD defines "blade strike" as a propeller having blade(s) bent beyond the repair limits set out in Hartzell Blade Repair and Overhaul Manual No 133B. Blade strikes trigger immediate inspection obligations either prior to further flight (if after 24 February 1995) or within short TIS windows (if before that date).

• Installation prohibition without inspection: The AD forbids installing hubs removed from specified Mitsubishi models onto other aircraft unless inspected according to the Hartzell Requirement Document. This restricts interchange of components across airframes without a specific inspection.

• Cross-references: The AD cites its relationship to other directives and service bulletins, including that the inspection is not the same as required by AD/PHZL/63 Amdt 1 (which calls up Hartzell Alert SB 170B), and that AD/PHZL/63 required fitment of "N" suffix blades. The AD also references FAA AD 95-01-02 and earlier FAA ADs that it supersedes or relates to.

These concepts determine who must act, what actions are mandatory, when they must be done, and what piece-part change alters recurrent requirements.

The AD directly affects a defined set of actors and indirectly affects others through compliance obligations and parts supply.

• Aircraft operators and owners: Owners and operators of Mitsubishi MU-2B-26A, MU-2B-36A, MU-2B-40, MU-2B-60 and any other MU-2 series aircraft that have been modified to carry the Hartzell HC-B4TN-5 family propellers are the primary duty-holders. They are required to ensure inspections and any corrective actions are performed in accordance with the Hartzell Requirement Documents and within the inspection windows set out in the AD.

• Maintenance organisations and licensed maintenance engineers: Those performing maintenance must follow Hartzell Alert SB A182A or A183A, and ASB A188, as invoked by the AD. The AD places procedural obligations on maintainers to carry out inspections and document compliance consistent with the Requirement Documents. They must also ensure that any hubs removed from the listed Mitsubishi models are not installed on other aircraft unless inspected per the Requirement Document.

• Parts suppliers and spare-parts managers: Firms that supply or manage propeller hubs or pilot tubes, including hub unit P/N 840-139 and pilot tubes P/N A1891A, are affected because the AD makes fitting that specific hub assembly the approved terminating action that alters inspection intervals. Suppliers will therefore face demand for specific part numbers to obtain the longer reinspection intervals.

• Aircraft owners or operators contemplating component interchange: The AD directly restricts reinstallation of hubs removed from specified models onto other aircraft unless the hub has been inspected in line with the Hartzell Requirement Document. This affects second-hand or recycled hub movements across aircraft types in the MU-2 family.

• Hartzell (manufacturer) and documentation owners: The AD delegates inspection procedures to Hartzell service bulletins, so Hartzell’s ASBs and manuals become the prescriptive technical standard for compliance. The AD also references Hartzell Blade Repair and Overhaul Manual No 133B for the definition of a blade strike.

• Regulatory bodies and inspectors: The AD is issued within the Commonwealth of Australia Civil Aviation Safety Authority (CASA) schedule of airworthiness directives under Civil Aviation Regulations 1998, Part 39. CASA will be the enforcing authority for compliance with this AD.

• Aircraft lessors and insurers: Although not named in the AD, parties with contractual or financial interests in the airworthiness of MU-2s with the subject propellers will be affected by the inspection regime and any changes to the aircraft’s maintenance status arising from compliance or non-compliance.

Geographical and model scope is narrow: only the specified Hartzell propeller family on specified MU-2 models or other MU-2 aircraft with those propellers installed. The AD also clarifies that the optional suffix letters in the propeller model designation (parentheses) do not alter applicability, thereby broadening coverage to all variations of that hub/blade family fitted to the listed aircraft.

This AD imposes specific duties on operators and maintainers and confers a limited right,an approved terminating action,to change inspection cadence.

Key duties

• Perform inspections per Hartzell ASB A182A or A183A as applicable, and ASB A188, for hubs and blades as invoked in "Requirement: 1" and "Requirement: 2" of the AD. The AD makes adherence to those documents mandatory.

• Observe the timing and recurrence requirements set out in the Compliance section. For hubs, this includes immediate or near-term inspections depending on hub TIS as of 24 February 1995 (see Compliance 1.a through 1.d), followed by reinspections at intervals not exceeding 600 hours TIS or 5 years until the terminating hub P/N 840-139 with pilot tubes P/N A1891A is fitted, after which inspections revert to intervals not exceeding 3000 hours TIS. For blades, the AD specifies inspection windows based on blade TIS bands and reinspection at each propeller overhaul or every 3000 hours TIS.

• Ensure that any propeller hubs removed from Mitsubishi MU-2B-26A, -36A, -40, or -60 series aircraft are not installed on other aircraft unless inspected in accordance with the Hartzell Requirement Document. This is an explicit prohibition conditioned on prior inspection.

• For blade strikes occurring after 24 February 1995, inspect the hub in accordance with the Requirement Document before further flight. For strikes before that date, perform the hub inspection within 10 hours TIS or by 30 April 1995, whichever occurs first.

• Apply the AD’s definition of blade strike when determining inspection obligations. The AD defines a blade strike as bending beyond the repair limits in Hartzell Blade Repair and Overhaul Manual No 133B, which places responsibility on operators and maintainers to consult that manual when assessing damage.

Conferred right / approved terminating action

• Fitment of hub unit P/N 840-139 with pilot tubes P/N A1891A, described as hubs with compressively rolled internal pilot tube bores, is specified as the action after which the reinspection interval changes from the more frequent 600 hours/5 years to 3000 hours TIS. In effect, operators have the right to perform that modification or replacement to obtain the longer inspection interval. The AD treats that part fitment as the terminating action for the repetitive 600-hour hub inspection requirement.

Interaction with other ADs and documents

• The AD makes clear that the inspection it requires is distinct from the inspection in AD/PHZL/63 Amdt 1, which calls up Hartzell Alert SB 170B. It also notes that AD/PHZL/63 required fitment of "N" suffix blades. Operators must therefore track multiple ADs and associated service bulletins to understand cumulative obligations.

Documentation duty

• Compliance requires following the Hartzell Requirement Document ASB procedures. Maintainers must therefore have access to and implement the technical steps in Hartzell ASB A182A/A183A and A188. The AD does not reproduce those procedures but makes them mandatory by reference.

Who decides compliance status

• The AD places the initial decision-making burden on the operator and the licensed maintenance personnel to schedule and perform inspections and to determine whether a blade strike has occurred under the manual’s limits. CASA, as the issuer of the AD, will be the regulatory body to audit or enforce compliance; however the AD itself does not specify enforcement penalties within its text.

The AD is published within the Commonwealth of Australia Civil Aviation Safety Authority schedule of airworthiness directives under the Civil Aviation Regulations 1998, Part 39, which establishes the regulatory context in which this directive operates. The document itself invokes mandatory inspections and actions but does not set out bespoke monetary fines or criminal sanctions in its text. Instead, it prescribes technical compliance obligations and cross-references Hartzell Requirement Documents for the detailed inspection and corrective procedures.

Practical enforcement architecture, as implied by the AD, is the standard AD regime: CASA lists the AD within its schedule of airworthiness directives, which makes the measures a regulatory requirement for continued airworthiness. This means that an affected aircraft’s airworthiness status will be contingent on compliance with the AD’s inspection and modification timetable; failure to comply would therefore affect whether the aircraft meets regulatory airworthiness requirements. The AD does not state particular penalties, or procedural enforcement steps such as suspension, notices, or pecuniary penalties. The AD also does not describe administrative review rights or appeal mechanisms in its text.

The AD also references FAA ADs and notes that FAA AD 95-01-02 supersedes several earlier FAA ADs. This indicates parallel regulatory activity in the United States; however, the AD does not describe cross-border enforcement mechanisms between CASA and the FAA. The AD relies on the Hartzell ASBs as the Requirement Documents, thereby making conformity with manufacturer prescriptions an enforceable element when CASA audits maintenance records.

Because the AD prescribes immediate and pre-flight inspection triggers in specified cases (for example, hubs that experienced blade strikes after 24 February 1995 must be inspected prior to further flight), enforcement can be operationally significant: non-compliance in those situations could result in an aircraft being flown in a state that the AD indicates is potentially unsafe. The AD does not, on its face, allocate pecuniary responsibility for inspections or parts, but by imposing mandatory maintenance it assigns the economic burden of compliance to the aircraft operator, owner, or maintenance contract counterparty responsible for ensuring continuing airworthiness.

In short, enforcement is through CASA’s airworthiness oversight and the regulatory status of ADs under Civil Aviation Regulations 1998, Part 39, but no specific penalties are contained within the AD text itself.

This AD is issued within the regulatory framework of the Commonwealth of Australia Civil Aviation Safety Authority and appears in the "SCHEDULE OF AIRWORTHINESS DIRECTIVES" under Civil Aviation Regulations 1998, Part 39. That placement means the AD operates as a component of the civil aviation regulatory regime governing continuing airworthiness in Australia. The AD explicitly cross-references other regulatory or manufacturer instruments; these interactions determine cumulative obligations for operators.

• Interaction with other ADs: The AD expressly differentiates its inspection requirement from AD/PHZL/63 Amdt 1, noting that AD/PHZL/63 calls up Hartzell Alert SB 170B and that AD/PHZL/63 required fitment of "N" suffix blades. Operators must therefore reconcile the requirements of AD/PHZL/64 with AD/PHZL/63 where both apply. The AD text also references FAA directives: it states that FAA AD 95-01-02 refers and supersedes FAA AD 93-01-09 Amdt 39-8463, FAA AD 93-09-04 Amdt 39-8583 and FAA AD 93-12-01 Amdt 39-8642. This indicates an international regulatory dialogue but does not itself create cross-border enforcement obligations.

• Delegation to manufacturer service documents: The AD incorporates Hartzell Alert SB A182A, A183A and A188 as the Requirement Documents. These service bulletins and the Hartzell Blade Repair and Overhaul Manual No 133B are treated as normative technical references for compliance. That means the AD interacts with commercial documentation owned by the manufacturer and makes those documents binding for inspected items. This creates a legal effect where manufacturer AMM/ASB material becomes the de facto technical standard for compliance under the AD framework.

• Affected maintenance and certification obligations: Because the AD prescribes mandatory inspections and replacement options, it interacts with an operator’s broader continuing airworthiness obligations under Part 39 and related civil aviation regulations. Compliance with the AD will feed into maintenance release processes and may affect an aircraft’s eligibility for flight under the operator’s airworthiness management system.

• Parts and modification approvals: The AD identifies a specific hub unit and pilot tube part numbers (hub P/N 840-139 with pilot tubes P/N A1891A) as the parts that, when fitted, change reinspection intervals. That interaction implies that fitting those parts is an approved modification for the purposes of this AD. The AD does not discuss additional certification or approval steps that may be required for parts installation; it simply states that the fitment is the terminating action.

• Documentation and repair manuals: The AD’s blade strike definition references the Hartzell Blade Repair and Overhaul Manual No 133B. That creates an interaction with approved repair documentation; operators and maintainers must consult that manual to assess whether a blade strike, as defined by the AD, has occurred.

The AD therefore interoperates with other ADs, manufacturer service documentation, maintenance and certification obligations under Part 39, and referenced manuals. It does not, within its own text, set out broader statutory enforcement penalties or appeal avenues, nor does it attempt to supersede other ADs beyond the references to FAA ADs where noted.

The AD record documents successive amendments and reasons for them. The text supplied is AD/PHZL/64 Amdt 2; the AD includes a brief history in its Background and the closing lines.

• Original issuance and triggers: The AD arose after in-service events: two propeller hub arm separations and one crack indication involving propellers from MU-2B-60 aircraft. Hartzell initially issued ASB A182 specifically for the MU-2B-60. Hartzell then extended the inspection to other MU-2 propellers due to similarity, which led to this AD addressing MU-2B-26A, -36A and -40 aircraft in addition to the -60.

• Amendment 1: Amendment 1 added the MU-2B-60 to the AD requirements. Amendment 1 also provided terminating action for the repetitive 600-hour hub inspection and introduced revised blade width and thickness limits intended to ensure reactionless mode vibration does not affect propeller airworthiness. The AD text records that Amendment 1 performed two substantive adjustments: expanding model coverage and providing a terminating technical route plus revised blade dimensional limits.

• Amendment 2: Amendment 2, which this supplied AD is, was raised to include the part numbers of hub units that are exempted from the 600-hour repetitive inspection. Specifically, the AD now lists hub unit P/N 840-139 with pilot tubes P/N A1891A as the hub/part combination that, once fitted, changes the reinspection interval to the 3000-hour interval. The final line of the AD states explicitly that Amendment 2 has been raised to include those part numbers.

• Relationship to FAA ADs: The AD notes that FAA AD 95-01-02 refers and supersedes multiple earlier FAA ADs: FAA AD 93-01-09 Amdt 39-8463, FAA AD 93-09-04 Amdt 39-8583 and FAA AD 93-12-01 Amdt 39-8642. While this is not an Australian amendment history per se, it documents related action in the FAA regulatory stream that provides an international context for the AD’s evolution.

• Notes and distinctions: The AD contains notes clarifying that the inspection required by this AD is not the same as that specified in AD/PHZL/63 Amdt 1 (which calls up Hartzell Alert SB 170B), and that AD/PHZL/63 required fitment of "N" suffix blades. These notes function as part of the historical record and alert operators to the need to comply with multiple, potentially overlapping directives.

The amendment history records incremental changes targeted at expanding scope (additional MU-2 models), providing a technical terminating action with specific part numbers, and adjusting blade dimensional criteria. The AD text ties these changes to specific operational incidents and to Hartzell’s updated documentation.

The AD text supplied contains no mention of litigation, legal challenges, or court proceedings. It records operational events (two propeller hub arm separations and one crack indication) as the background for regulatory action and documents amendments addressing those safety concerns. The AD itself is presented as an administrative regulatory instrument within the Civil Aviation Safety Authority schedule of airworthiness directives and does not report any judicial or administrative litigation history in its text.

Because the AD invokes Hartzell Requirement Documents and references FAA ADs, the AD indicates regulatory alignment and cross-referencing rather than adversarial legal proceedings. The absence of any litigation record in the AD text means there is no source-grounded material in this document to describe contested enforcement actions, judicial review, injunctions, or case law regarding this AD.

For readers seeking litigation history, the AD supplies two relevant facts that may be starting points for external research, but do not themselves constitute litigation: the AD references other ADs (for example, AD/PHZL/63 Amdt 1 and various FAA ADs) and calls up specific Hartzell ASBs and manuals. Any litigation arising from enforcement of the AD, disputes over interpretation of Requirement Documents, or controversies about parts interchangeability are not documented here. Accordingly, the AD provides no source-based content on court decisions, administrative appeals, or settled disputes.

If legal questions or disputes arise in practice,such as disagreements over whether a hub required inspection prior to transfer between airframes, or over the sufficiency of a Hartzell ASB action,those would need to be investigated in external, authoritative legal or administrative records because this AD does not include any litigation history or adjudicative outcomes.

The AD contains multiple procedural and technical nuances that can create compliance surprises if not noted carefully. Below are the specific pitfalls and fine points grounded in the AD text.

• Parenthetical letters do not narrow applicability: The AD’s Applicability notation says parentheses indicate presence or absence of additional letter(s) which vary hub and blade model designation, and that the Directive applies regardless of whether these letters are present. Practically, this means checking a propeller data plate for suffix letters is insufficient; operators must treat all permutations of the HC-B4TN-5... designation as captured by the AD.

• Multiple inspection regimes exist and differ from other ADs: Note 1 states that the inspection required by AD/PHZL/64 is not the same as AD/PHZL/63 Amdt 1 (which calls up Hartzell Alert SB 170B). Operators who attempt to follow only the inspection procedures in other ADs or the wrong Hartzell SB risk non-compliance.

• Short, date-specific inspection windows: The AD ties certain initial inspection deadlines to a specific calendar date, 24 February 1995, with backstops such as "within 10 hours TIS from 24 February 1995 or by 30 April 1995, whichever occurs first" for certain hubs. That creates a historical timing anchor that may complicate record checks for aircraft with incomplete logbooks. For hubs of unknown TIS, the same short window applies, which imposes immediate inspection obligations in that historical context.

• Blade strike definition is procedural, not merely factual: The AD defines a blade strike as a blade bent beyond repair limits in Hartzell Blade Repair and Overhaul Manual No 133B. That ties the operational determination of a strike to the content of that manual. If the manual is interpreted differently or newer revisions change limits, the AD’s determination depends on the version used at the time of inspection unless otherwise specified in the Requirement Documents. Operators should therefore document which manual revision they applied when determining whether a blade strike occurred.

• Installation prohibition without inspection affects part interchange: The AD states that propeller hubs removed from MU-2B-26A, -36A, -40 or -60 aircraft must not be installed on any other aircraft unless inspected per Hartzell ASB A182A or A183A dated March 11, 1994. This is an operator-level restriction on reusing hubs across aircraft; failure to inspect before installation would contravene the AD.

• Banded blade inspection requirements require careful hour accounting: The AD divides blade inspection timing into bands (≥2900, 2201-2900, ≤2200 hours TIS) with distinct deadlines: within 100 hours for the high band, prior to 3000 hours for the mid band, and within 800 hours for the low band. Operators must track individual blade hours, not just propeller averages, to apply the correct schedule.

• Terminating action is part-number specific: The AD identifies hub P/N 840-139 with pilot tubes P/N A1891A as the parts that, when fitted, allow the longer 3000-hour intervals. Operators fitting other hub variants cannot assume they have obtained the terminating action. Amendment 2 was specifically raised to include these part numbers, so accurate part-number verification is essential.

• Reinspection cadence change is conditional upon fitment: Until the terminating hub is fitted, the short 600-hour or 5-year reinspection interval applies. Fitting the terminating part is therefore a material change to maintenance economics and scheduling. Operators should not assume the shorter interval is optional.

• The AD cross-references multiple Hartzell documents: Compliance requires access to and execution of the procedures in Hartzell ASB A182A/A183A and ASB A188. There is no procedural text in the AD itself. If maintainers lack these documents or use an incorrect revision, they may not meet the AD’s requirements.

• Historical dates and present-day recordkeeping: The AD’s anchor to 24 February 1995 and the specified near-term deadlines means that, for operators reviewing decades-old aircraft, historical compliance status will need to be reconstructed from maintenance records. Hubs with unknown TIS were required to be inspected within the same early window as hubs with ≥3000 hours; records gaps may lead to immediate obligations to inspect.

• Interaction with AD/PHZL/63 and previous fitment requirements: Note 2 states that AD/PHZL/63 Amdt 1 requires fitment of the "N" suffix blades. If an operator has followed AD/PHZL/63, that action interacts with the current AD; operators must be careful to reconcile parts and inspections across both ADs to avoid missing obligations.

• Pre-flight inspection requirement after blade strike: For blade strikes after 24 February 1995, hubs must be inspected prior to further flight. Operators who restart operations without a documented inspection risk operating in a condition the AD deems unsafe.

In practice, the combination of historical deadlines, part-number-specific terminating action, cross-references to other ADs and manufacturer manuals, and banded hour thresholds for blades creates opportunities for inadvertent non-compliance unless operators maintain precise logs, hold the correct Hartzell documents, and verify part numbers during maintenance and parts procurement.

The AD prescribes a clear compliance pathway by reference to Hartzell Requirement Documents and by specifying inspection triggers, intervals, and an approved terminating action. Below are concrete, actionable steps grounded in the AD text.

1. Identify applicability and affected components

   • Check aircraft type: confirm whether the aircraft is a Mitsubishi MU-2B-26A, MU-2B-36A, MU-2B-40, MU-2B-60, or any MU-2 series aircraft modified to carry HC-B4TN-5(D,G,J)L/LT10282(N)(B,K)-5.3R propellers. Remember that parentheses in the model designation are not limiting; treat all permutations as covered.

2. Obtain and review Requirement Documents

   • Obtain Hartzell Alert SB A182A or A183A, as applicable, and Hartzell Alert SB A188. These documents contain the specific inspection procedures and corrective actions that the AD makes mandatory. Also have Hartzell Blade Repair and Overhaul Manual No 133B available for blade strike definitions and repair limits.

3. Determine historical hour bands and strike history

   • For each propeller hub and blade, determine total time since new (TIS) and whether any blade strikes have occurred, referencing maintenance logs and repair records. The AD references 24 February 1995 as the anchor date for initial window calculations.

4. Perform required inspections per the AD timing

   • Hubs: a. If hub TIS ≥3000 hours as of 24 February 1995, or hub TIS is unknown, inspect the hub in accordance with the Hartzell Requirement Document within 10 hours TIS from 24 February 1995 or by 30 April 1995, whichever occurs first. Thereafter, reinspect at intervals not exceeding 600 hours TIS or 5 years TIS, whichever occurs first, until hub P/N 840-139 with pilot tubes P/N A1891A is fitted. Once the specified hub with compressively rolled pilot tube bores is fitted, reinspect at intervals not exceeding 3000 hours TIS. b. If hub TIS <3000 hours as of 24 February 1995, inspect prior to reaching 3010 hours TIS or within 200 hours from 24 February 1995 or by 24 February 1996, whichever occurs first. Thereafter, follow the same reinspection steps as in (a) until the terminating hub is fitted. c. Regardless of TIS, any propeller that experienced a blade strike prior to 24 February 1995 must be inspected within 10 hours TIS from 24 February 1995 or by 30 April 1995, whichever occurs first, then reinspected at intervals not exceeding 600 hours TIS or 5 years until the terminating hub is fitted. d. Any hub experiencing a blade strike after 24 February 1995 must be inspected in accordance with the Requirement Document prior to further flight. Thereafter, reinspect at intervals not exceeding 600 hours TIS or 5 years until the terminating hub is fitted.

   • Blades: 2. For blades with ≥2900 hours TIS, inspect within 100 hours TIS from 24 February 1995. Thereafter, reinspect at each propeller overhaul or at intervals not exceeding 3000 hours TIS. 2.a For blades with >2200 and <2900 hours TIS as of 24 February 1995, inspect prior to blades reaching 3000 hours TIS. Thereafter, reinspect at overhaul or every 3000 hours TIS. 2.b For blades with ≤2200 hours TIS, inspect within 800 hours TIS from 24 February 1995. Thereafter, reinspect at overhaul or every 3000 hours TIS.

5. Use the Hartzell Blade Repair Manual for blade strike assessment

   • Apply the repair limits in Hartzell Blade Repair and Overhaul Manual No 133B when deciding whether a blade strike has occurred and hence whether the hub inspection requirement is triggered.

6. Document inspections and corrective actions

   • Record all inspections, findings, repairs, and parts installed. Specifically log the part numbers of hubs and pilot tubes installed. If the terminating hub unit P/N 840-139 with pilot tubes P/N A1891A is fitted, record that fitment as it materially changes the inspection schedule to reinspection intervals not exceeding 3000 hours TIS.

7. Do not install hubs from listed MU-2s onto other aircraft without prior inspection

   • Hubs removed from Mitsubishi MU-2B-26A, -36A, -40 or -60 series aircraft must not be installed on any other aircraft unless inspected according to Hartzell ASB A182A or A183A dated March 11, 1994.

8. Coordinate parts procurement with certified suppliers

   • If electing to fit the terminating hub and pilot tubes, confirm part numbers (hub P/N 840-139, pilot tubes P/N A1891A) and acquire from approved suppliers. Ensure installation is performed and signed off by authorised maintenance personnel according to the Requirement Document.

9. Align operations with other ADs where applicable

   • Reconcile compliance with AD/PHZL/63 Amdt 1 and any other relevant directives, noting the AD’s explicit statement that its inspection requirement is not the same as that called up by AD/PHZL/63.

10. Plan for operational impact and maintenance scheduling

    • Until the terminating hub is fitted, incorporate 600-hour or 5-year reinspection intervals into maintenance planning. Consider the economic and downtime implications of either adhering to the frequent inspections or fitting the terminating hub assembly to obtain longer intervals.

Who pays and who decides

• The economic burden of inspections and any parts or repairs is placed on the aircraft operator or owner, or their maintenance contract counterpart, because the AD imposes maintenance actions to preserve airworthiness. Licensed maintenance organisations and engineers must decide the technical adequacy of inspection outcomes by following the Hartzell Requirement Documents.

By following the Hartzell ASBs and recording inspections and any part substitutions to the specified part numbers, operators will meet the AD’s compliance requirements as set out in the document.