{"id":"F2006B06222","name":"AD/PHZL/64 Amdt 2 - Hub Pilot Tube Bore","slug":"ad-phzl-64-amdt-2-hub-pilot-tube-bore","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47135,"registerId":"commonwealth-F2006B06222-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PHZL/64 Amdt 2 - Hub Pilot Tube Bore","content":"![](image.001.png)Propellers \\- Variable Pitch \\- Hartzell\n\nAD/PHZL/64\n\nAmdt 2\n\n  \nHub Pilot Tube Bore 8/95 DM\n\nApplicability: All HC-B4TN-5(D,G,J)L/LT10282(N)(B,K)-5.3R propellers installed on Mitsubishi MU-2B-26A, MU-2B-36A, MU-2B-40 or MU-2B-60 aircraft or any other MU-2 series aircraft which has been modified by installation of the subject propeller.\n\nNote: The parentheses indicate the presence or absence of additional letter(s) which vary the basic propeller hub and propeller blade model designation. This Directive applies regardless of whether these letters are present or absent in the propeller hub and blade model designation.\n\nRequirement: 1. Action in accordance with Hartzell Alert SB A182A or A183A, as applicable. Propeller hubs removed from Mitsubishi model MU-2B-26A, -36A, -40 or -60 series aircraft must not be installed on any other aircraft unless an inspection has been performed in accordance with Hartzell ASB A182A or A183A dated March 11, 1994.\n\n2. Action in accordance with Hartzell Alert SB A188.\n\nNote 1: The inspection required by this Directive is not the same as specified in AD/PHZL/63 Amdt 1 which calls up Hartzell Alert SB 170B.\n\nNote 2: AD/PHZL/63 Amdt 1 requires fitment of the “N” suffix blades.\n\nNote 3: FAA AD 95-01-02 Amdt 39-9113 refers and supersedes FAA AD 93-01-09\n\nAmdt 39-8463, FAA AD 93-09-04 Amdt 39-8583 and FAA AD 93-12-01 Amdt 39-\n\n8642.\n\nCompliance: 1. a. If hub total time since new is 3000 hours time in service or greater as of 24 February 1995 or if the hub total time in service is unknown, inspect hub in accordance with the Requirement Document within 10 hours time in service from 24 February 1995 or by 30 April 1995, whichever occurs first.\n\nThereafter, reinspect at intervals not exceeding 600 hours time in service (TIS) or 5 years TIS, whichever occurs first, until hub unit P/N 840-139 with pilot tubes P/N A1891A has been fitted. Once a hub with compressively rolled internal pilot tube bores has been fitted, reinspect in accordance with the Requirement Document at intervals not exceeding 3000 hours time in service.\n\n1. b. If hub total TIS is less than 3000 hours TIS inspect hub in accordance with the Requirement Document prior to reaching 3010 hours TIS or within 200 hours TIS from 24 February 1995 or by 24 February 1996, whichever occurs first.\n\nThereafter, reinspect hubs at intervals not exceeding 600 hours TIS or 5 years TIS whichever occurs first, until hub unit P/N 840-139 with pilot tubes P/N A1891A has been fitted. Once a hub with compressively rolled internal pilot tube bores has been fitted, reinspect in accordance with the Requirement Document at intervals not exceeding 3000 hours time in service.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n1. c. Regardless of time since new, any propeller that has experienced a propeller blade strike\\* prior to 24 February 1995, must have the hub inspected IAW the Requirement Document within 10 hours TIS from 24 February 1995 or by 30 April 1995, whichever occurs first.\n\nThereafter, reinspect hub at intervals not exceeding 600 hours TIS or 5 years TIS, whichever occurs first, until hub unit P/N 840-139 with pilot tubes P/N A1891A has been fitted. Once a hub with compressively rolled internal pilot tube bores has been fitted, reinspect in accordance with the Requirement Document at intervals not exceeding 3000 hours TIS.\n\n    d. Regardless of time since new, any propeller hub assemblies that experience a blade strike\\* after 24 February 1995 must have the hub inspected in accordance with the Requirement Document prior to further flight.\n\nThereafter, reinspect hub at intervals not exceeding 600 hours TIS or 5 years TIS, until hub unit P/N 840-139 with pilot tubes P/N A1891A has been fitted. Once a hub with compressively rolled internal pilot tube bores has been fitted, reinspect in accordance with the Requirement Document at intervals not exceeding 3000 hours TIS.\n\n    2. For blades with 2900 or more hours TIS inspect within 100 hours TIS from 24 February 1995.\n\nThereafter, reinspect in accordance with the Requirement Document at each propeller overhaul or at intervals not exceeding 3000 hours TIS, whichever occurs first.\n\n2. a. For blades with less than 2900 hours TIS but more than 2200 hours TIS by 24 February 1995 inspect prior to blades reaching 3000 hours TIS.\n\nThereafter, reinspect in accordance with the Requirement Document at each propeller overhaul or at intervals not exceeding 3000 hours TIS, whichever occurs first.\n\n2. b. For blades with 2200 hours or less TIS inspect within 800 hours time in service from 24 February 1995.\n\nThereafter, reinspect in accordance with the Requirement Document at each propeller overhaul or at intervals not exceeding 3000 hours TIS, whichever occurs first.\n\nNote: \\*A blade strike is defined as a propeller having blade/s that have been bent beyond the repair limits specified in Hartzell Blade Repair and Overhaul Manual No 133B.\n\nBackground: There has been two propeller hub arm separations and one crack indication involving propellers from MU-2B-60 aircraft. Hartzell issued ASB A182 specifically for the MU-2B-60 aircraft. Due to the similarity of the MU-2 propeller assembly, Hartzell has extended the inspection to include the propellers fitted to the MU-2B-26A, -36A and -40 series aircraft.\n\nAmendment 1 added the MU-2B-60 to the AD requirements, provided terminating action for the repetitive 600 hourly hub inspection and introduced the revised blade width and thickness limits to ensure REACTIONLESS MODE vibration does not affect the propeller airworthiness.\n\nAmendment 2 has been raised to include the part numbers of the hub units that are exempted from the 600 hour repetitive inspection.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"Amendment 2 narrows the recurrent inspection burden by identifying a specific hub/pilot tube part-number combination (hub P/N 840-139 with pilot tubes P/N A1891A) that, when fitted, changes the inspection regime from 600‑hour/5‑year intervals to 3000‑hour intervals. Earlier amendments had broadened applicability (adding MU-2B-60) and added requirements (blade limits). Amendment 2 therefore changes the operational scope by adding a concrete terminating action and exempting those upgraded parts from the more frequent inspections, shifting ongoing compliance costs toward operators who do not install the upgraded hub."},"complexity_factors":["Multiple conditional inspection schedules based on hub TIS thresholds (>=3000, <3000) and blade TIS thresholds (>=2900, 2200–2900, <=2200).","Event-driven rules (blade strike before/after a cut‑off date) that change required timing and impose immediate actions.","Repetitive inspection intervals that change after a specific terminating action (fit hub P/N 840-139 with pilot tubes P/N A1891A).","Cross-references to multiple external Hartzell service documents (ASB A182A, A183A, A188) and a blade repair manual (No 133B) for substantive inspection procedures and limits.","Several subclauses (1.a, 1.b, 1.c, 1.d, 2, 2.a, 2.b) with different deadlines and options (hours, calendar dates), increasing scheduling complexity.","Defined operational term with technical scope (\"blade strike\" defined by repair limits), requiring technical judgement by maintenance personnel.","Notes and prior amendments referenced (links to other ADs and FAA ADs) that require cross-checking for full compliance history and compatibility."],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires inspections and follow-up inspections of specific Hartzell variable-pitch propeller hubs and blades installed on Mitsubishi MU-2 series aircraft. The inspections must be carried out in accordance with Hartzell Alert Service Bulletins (ASBs) called up by this Directive: A182A or A183A (as applicable) and A188 (see \"Requirement\").\n\n- Sets different initial inspection timings depending on the hub or blade hours (time-in-service, TIS) and whether a blade strike has occurred (see \"Compliance\"). After initial inspections, it prescribes recurring inspection intervals until a specified upgraded hub assembly is fitted. Once a hub with compressively rolled internal pilot tube bores — identified as hub unit P/N 840-139 with pilot tubes P/N A1891A — is fitted, the repetitive inspection interval is relaxed to 3000 hours TIS.\n\n- Provides a terminating action for the short-interval hub inspections by fitting the specified hub/pilot tube part numbers (P/N 840-139 / A1891A).\n\nWho this affects\n\n- Aircraft owners/operators and maintenance organisations who operate Mitsubishi MU-2 aircraft fitted with Hartzell HC-B4TN-5(D,G,J)L/LT10282(N)(B,K)-5.3R propellers, and any other MU-2 series aircraft modified with these propellers (see \"Applicability\").\n\n- Maintenance, repair and overhaul (MRO) businesses that carry out the inspections and any follow-on repairs or hub replacements called for by the Hartzell ASBs.\n\nWhy it matters (stated purpose and operational effect)\n\n- The Directive is a safety measure motivated by reported hub arm separations and crack indications on MU-2B-60 propellers; Hartzell issued service information and extended the inspection requirement to similar MU-2 propeller assemblies. The Directive requires operators to inspect hubs and blades to detect damage or wear that could lead to in-flight separation or other unsafe conditions (Background).\n\nHow it works in practice\n\n- Inspection timing rules (selected highlights):\n  - Requirement 1.a: If a hub has 3000 or more hours TIS (or TIS is unknown) as of 24 Feb 1995, inspect within 10 hours TIS of that date or by 30 Apr 1995. Then re-inspect every 600 hours TIS or 5 years, whichever first, until the upgraded hub P/N 840-139 with pilot tubes P/N A1891A is fitted; after that, inspections move to 3000-hour intervals.\n  - Requirement 1.b: If hub TIS is less than 3000 hours, inspect before reaching 3010 hours or within 200 hours TIS from 24 Feb 1995 or by 24 Feb 1996 (whichever comes first), then re-inspect every 600 hours or 5 years until the upgraded hub is fitted.\n  - Requirement 1.c/d: Any propeller that had a blade strike before 24 Feb 1995 must be inspected very soon (within 10 hours TIS or by 30 Apr 1995); any blade strike after 24 Feb 1995 requires inspection before next flight. Re-inspection intervals follow the same 600-hour/5-year rule until the upgraded hub is fitted.\n  - Requirements 2/2.a/2.b: Blade inspection rules depend on blade hours (>=2900, 2200–2900, or <=2200) with specified windows for initial inspection and thereafter at overhaul or every 3000 hours TIS.\n\n- Definitions and treatment: A \"blade strike\" is specifically defined as a blade bent beyond Hartzell's repair limits (Hartzell Blade Repair and Overhaul Manual No 133B).\n\nPurpose-claims and testing them against costs, incentives and risks\n\n- Stated purpose: detect and prevent hub failures after observed separations/cracks (Background). The concrete mechanism: frequent inspections targeted at higher-age hubs/blades and after blade-strike events; and an engineered terminating action (fit upgraded hub P/N 840-139 with pilot tubes P/N A1891A) that materially reduces inspection frequency.\n\n- Who pays: aircraft owners/operators pay inspection and repair costs, and potentially the cost of replacing hubs to obtain the terminating action. MROs and parts suppliers receive the work and parts revenue.\n\n- Incentives created: operators have a clear economic incentive to replace older hubs with the specified upgraded unit (P/N 840-139/A1891A) to move from 600-hour/5-year recurring inspections to 3000-hour intervals. That increases demand for the upgraded part and for qualified installation work.\n\n- Compliance burden and administrative requirements: tracking hub and blade TIS, recording any blade strikes (and determining whether they exceed repair limits), and applying multiple time-based and event-based inspection rules increases recordkeeping and scheduling complexity for operators and MROs (see Compliance clauses). The Directive depends on external Hartzell documents, so access to and correct application of those ASBs is essential.\n\n- Possible trade-offs and risks: short-term costs and aircraft downtime for frequent inspections vs. longer-term lower recurring inspection costs after hub upgrade; potential supply constraints or pricing pressure for the upgraded hub; risk of inconsistent application if inspection criteria in the referenced ASBs are interpreted differently across MROs; and the administrative risk of tracking historical TIS and blade-strike history required by the Directive.\n\nKey implementation points operators must note\n\n- Comply exactly with the Hartzell ASBs specified by the Directive (Requirement).\n- Track hub and blade TIS and blade-strike history to apply the correct inspection timetable (Requirements 1.a–1.d and 2/2.a/2.b).\n- Installing hub P/N 840-139 with pilot tubes P/N A1891A is the explicit means to reduce inspection frequency (terminating action)."},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":true,"description":"The original directive (implied by Amendment 1 background) was specific to the MU-2B-60 aircraft. Amendment 1 expanded scope to include MU-2B-26A, -36A and -40 series. Amendment 2 further expands by adding specific part number exemptions (hub unit P/N 840-139 with pilot tubes P/N A1891a) that allow operators to exit the repetitive 600-hour inspection cycle. The directive has evolved from a narrow safety response to a broader fleet-wide maintenance management instrument with conditional compliance pathways."},"complexity_factors":["Multiple conditional compliance pathways based on hours flown (TIS — Time In Service), with four distinct hub inspection tracks (1a, 1b, 1c, 1d) and three blade inspection tracks (2, 2a, 2b)","Nested time-based triggers using multiple reference dates (24 February 1995) and alternative deadlines ('whichever occurs first' logic appears 8 times)","Cross-references to four external Hartzell documents (Alert SB A182A, A183A, A188, and Manual No 133B) without reproducing their content","Reference to superseded FAA directives and related Australian ADs (AD/PHZL/63 Amdt 1) creating interdependence with other regulatory instruments","Technical part number dependencies for terminating action (hub unit P/N 840-139 with pilot tubes P/N A1891A) requiring precise component tracking","Definition of 'blade strike' relies on external manual (Hartzell Blade Repair and Overhaul Manual No 133B) rather than inline definition"],"plain_english_summary":"CASA’s AD requires mandatory inspections and maintenance of Hartzell HC-B4TN-5 series propellers on specified Mitsubishi MU-2 models to check the propeller hub “pilot tube bore” for cracks or damage, with inspection intervals set by hours and blade‑strike history, and limits on swapping hubs between aircraft unless checked. An upgraded hub (P/N 840‑139 with A1891A pilot tubes) allows reduced inspection frequency.\n\nIt responds to hub failures on MU-2B‑60s and aims to detect fatigue before catastrophic loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-phzl-64-amdt-2-hub-pilot-tube-bore","history":"/api/acts/ad-phzl-64-amdt-2-hub-pilot-tube-bore/history","analysis":"/api/acts/ad-phzl-64-amdt-2-hub-pilot-tube-bore/analysis","conflicts":"/api/acts/ad-phzl-64-amdt-2-hub-pilot-tube-bore/conflicts","importantCases":"/api/acts/ad-phzl-64-amdt-2-hub-pilot-tube-bore/important-cases","documents":"/api/acts/ad-phzl-64-amdt-2-hub-pilot-tube-bore/documents"}}