{"id":"F2006B06216","name":"AD/PHZL/54 - Hard Alloy Propeller Blades","slug":"ad-phzl-54-hard-alloy-propeller-blades","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47115,"registerId":"commonwealth-F2006B06216-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PHZL/54 - Hard Alloy Propeller Blades","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPropellers \\- Variable Pitch \\- Hartzell\n\nAD/PHZL/54 Hard Alloy Propeller Blades 1/87 DM\n\nApplicability: All turboprop aircraft fitted with Hartzell propeller blades made from hard alloy.\n\nNote: Hard alloy blades are identified by the letter\"H\" immediately following the blade design number eg. T10282 HB.\n\nRequirement: 1. All turboprop hard alloy propeller blades which are not painted with Polane paint, or have had de-ice boots replaced since manufacture where it cannot be positively determined that the boots have been fitted onto an approved paint surface, are to be removed from service and reworked in accordance with Section V of Hartzell Blade Specification Manual 133-( ) and Hartzell SB No 138.\n\nNote: All blades are to be anodised before painting (SB 138 Para D refers).\n\n2. (a) Visually inspect the propeller blades in the area from the blade clamp to six inches outboard of the deice boot for scratches, dents, nicks or other signs of exposed bare metal where surface corrosion could initiate. Also inspect the paint coating for signs of deterioration, for example, cracks, chips, bubbles, flaking, blisters, etc., which might indicate the presence of corrosion underneath the paint.\n\n2. (b) Visually inspect the blade deice boot for looseness, bubbles or detachment of the boot. Visually inspect the deice boot adhesive for adequate coverage with protective paint coating, and sealant protection. No bare metal may be exposed.\n\n2. (c) Propellers with blade surface irregularities as described in A and B above are to be removed from service before further flight and treated in accordance with Para C of Hartzell S.B. 138.\n\nNote: Because of the critical nature and extremely high propagation rate of cracks in this area, particular care is to be used when carrying out the daily inspection.\n\nCompliance: 1. Within 25 hours time in service after 30 December 1986.\n\nNote 1: All hard alloy blades are to be overhauled at 3000 hours time in service or 5 years whichever occurs first.\n\nNote 2: Eddy current inspection in accordance with Section V of Manual 133-( ) is to be carried out at each blade rework.\n\n2. At each daily inspection after 30 December 1986.\n\nNote: This Directive shall be entered on the Maintenance Release as maintenance required. The inspection required by Para 2 may be performed by the pilot in command in which case certification is to be made by entering AD/PHZL/54 against the daily inspection certification of the Maintenance Release. A copy of this Airworthiness Directive is to be kept in the aircraft.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: A recent after flight incident in which a blade was discovered with a crack across 67% of the chord has highlighted the need for a more critical inspection of hard alloy blades. The need for a more effective corrosion protection of this type blade is also required.\n\nThe crack started at a small corrosion pit at the edge of the deice boot and moved rapidly across the blade.","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":3,"scope_assessment":{"changed":false,"description":"This AD stays within its original safety-focused scope: it targets corrosion-initiated cracking on Hartzell hard-alloy blades and prescribes inspection, rework and protective painting/anodising measures. It does not expand to unrelated regulatory domains or add new categories of aircraft or parts beyond the stated applicability. The instrument tightens and clarifies maintenance actions and record-keeping but does not materially broaden the subject matter beyond its original intent to prevent rapid crack propagation from corrosion near deice boots."},"complexity_factors":["Single-airworthiness-directive format with clear applicability (Hartzell hard alloy blades)","Two principal operative requirements (rework/removal; daily visual inspection) with several sub-elements","Cross-references to external technical documents (Hartzell Blade Specification Manual Section V and Hartzell SB No. 138, Manual 133)","Specific technical methods required at overhaul (eddy-current inspection)","Compliance timing rules and a recurring inspection duty (daily) plus overhaul interval (3,000 hours / 5 years)","A proviso allowing pilots to perform daily inspections and certify on Maintenance Release (adds operational nuance)","Notes on painting/anodising and where to record the AD (administrative requirements)"],"plain_english_summary":"**What this directive does (mechanics)**\n\n- Applies to: all turboprop aircraft that use Hartzell propeller blades made from \"hard alloy\" (those with an \"H\" after the blade design number, e.g. T10282 HB). (Applicability)\n\n- Requires immediate rework/removal from service in certain cases (Requirement 1):\n  - If a hard-alloy blade is not painted with Polane paint, OR\n  - If the de-ice boot has been replaced since manufacture and it cannot be positively determined that the boot was fitted onto an approved paint surface,\n  then the blade must be removed from service and reworked following Hartzell Blade Specification Manual Section V and Hartzell Service Bulletin (SB) No. 138. Blades must be anodised before painting (SB 138). (Requirement 1, Note)\n\n- Requires recurring visual inspections (Requirement 2):\n  - At each daily inspection, inspect the blade from the blade clamp to six inches outboard of the deice boot for scratches, dents, nicks or any exposed bare metal where corrosion could start, and inspect the paint for cracking, chipping, bubbling, flaking, blisters, etc.;\n  - Inspect the deice boot for looseness, bubbles, detachment, and check that the adhesive area has paint/sealant protection with no bare metal exposed;\n  - If any of these surface irregularities are found, the propeller must be removed from service before further flight and treated per Para C of Hartzell SB 138. The directive emphasises particular care because cracks in this area can grow very rapidly. (Requirement 2)\n\n- Timelines and further technical requirements (Compliance and Notes):\n  - The initial compliance deadline for the rework/removal requirement was within 25 hours time in service after 30 December 1986 (historical date shown in the AD). (Compliance 1)\n  - Daily visual inspection requirement applies at each daily inspection after that date. The AD must be recorded on the aircraft Maintenance Release and a copy kept on board. The pilot-in-command may perform the daily inspection, but must certify it by entering AD/PHZL/54 against the daily inspection certification on the Maintenance Release. (Compliance 2; Notes)\n  - All hard alloy blades must be overhauled at 3,000 hours time-in-service or 5 years, whichever comes first. An eddy-current inspection per Section V of Manual 133 is required at each blade rework. (Notes)\n\n**Who this affects and who pays**\n\n- Directly affected: aircraft owners/operators, maintenance organisations and personnel, and pilots of turboprop aircraft with Hartzell hard-alloy blades. (Applicability; Requirement; Compliance)\n- Who pays: operators pay for rework, painting (Polane), anodising, eddy-current inspections, possible replacement of deice boots, downtime while the aircraft is out of service, and any additional overhaul costs at 3,000 hours/5 years. Maintenance organisations perform the work and must make compliance entries on the Maintenance Release. (Requirement 1; Notes)\n\n**Why the regulator says it matters (official rationale) and how that maps to costs and incentives**\n\n- Official rationale: an after-flight incident found a blade cracked across 67% of the chord. The crack reportedly started at a small corrosion pit at the edge of the deice boot and propagated rapidly. The AD claims more critical inspection and improved corrosion protection are needed to prevent such rapid crack growth. (Background)\n\n- Practical implications, trade-offs and implementation risks:\n  - Safety benefit claimed: more frequent, tighter visual inspection and mandated rework/painting are intended to reduce the probability of corrosion-initiated cracking in a high-risk area. (Requirement 2; Note)\n  - Direct costs: labour, parts (paint, anodising, sealants, possible replacement boots), non-operational hours (downtime), and specialist inspections (eddy-current testing at overhaul). These costs fall on aircraft owners/operators and maintenance providers. (Requirement 1; Notes)\n  - Compliance burden and discretion: the AD cross-references Hartzell manuals and SB 138; operators need access to those technical documents and must determine whether a boot was fitted onto an \"approved paint surface.\" That determination can create practical ambiguity and discretionary judgement for maintenance staff, potentially increasing time and administrative effort. (Requirement 1)\n  - Operational substitution effects: to meet the AD’s conditions, operators may choose repainting with Polane or earlier rework to avoid recurrent removal, or consider different blade types at longer term overhaul decisions. These are commercial choices driven by compliance cost vs. operational needs. (Requirement 1; Notes)\n  - Effects on competition and service providers: the requirement to follow Hartzell’s manuals and SB creates demand for compliant rework and inspections; independent maintenance organisations capable of following Hartzell procedures can compete, but the AD raises the value of access to the OEM’s technical data and parts. That creates concentrated demand for providers who can demonstrate compliance competence. (Requirement 1)\n  - Enforcement and record-keeping: the AD must be entered on the Maintenance Release and a copy kept on the aircraft; pilots may perform daily inspection and certify it. This shifts some compliance activity to pilots (who may have limited inspection expertise) while keeping formal accountability with the operator via the Maintenance Release. (Compliance 2; Note)\n\n**Concrete behaviour changes required**\n\n- Operators must inspect blades daily in the specified area or have the pilot do so and certify it. (Requirement 2; Compliance 2)\n- If paint or boot condition is uncertain or defects are found, blades must be removed and reworked per Hartzell procedures, including anodising and eddy-current inspection at rework/overhaul. (Requirement 1; Notes)\n- Operators must schedule periodic overhaul (3,000 hours or 5 years) and record the AD on the Maintenance Release and keep a copy onboard. (Notes; Compliance)\n\n**Source claim vs. cost/incentive mapping**\n\n- The AD’s stated purpose (prevent crack initiation and rapid propagation from corrosion near deice boots) is a targeted safety measure tied to a specific incident. Mechanically, it increases inspection frequency and imposes rework/painting standards. The safety benefit accrues to anyone flying those blades; the cost is concentrated on the owners/operators who must perform the additional work and accept aircraft downtime. The AD channels maintenance work toward operators who follow Hartzell’s specified rework and inspection processes, creating demand for technicians with the relevant manuals and capabilities. (Background; Requirement; Notes)"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope addressing the specific safety risk of corrosion-induced cracking in Hartzell hard alloy propeller blades. The requirements (rework, painting, daily inspections, periodic overhauls) all directly address the identified hazard from the 'after flight incident' described in the Background section. No scope creep is evident."},"complexity_factors":["Multiple cross-references to external technical documents (Hartzell Blade Specification Manual 133, Hartzell Service Bulletin 138) without full titles or dates","Conditional logic requiring determination of paint history ('cannot be positively determined')","Dual compliance pathways (one-time rework vs. recurring inspections)","Specific measurement requirements ('six inches outboard of the deice boot')","Nested inspection criteria (2a, 2b, 2c with cross-references between them)","Dual compliance timelines (25 hours for rework, ongoing daily inspections)","Certification requirements involving Maintenance Release documentation","Technical terminology requiring specialist aviation knowledge (anodising, eddy current inspection, chord, time in service)"],"plain_english_summary":"This CASA Airworthiness Directive mandates urgent maintenance and daily visual inspections of Hartzell \"hard alloy\" propeller blades used on turboprops, and removal/repair where protective coatings or proper boot preparation are missing.  \n\nIt affects owners, operators, maintenance engineers and pilots because corrosion under de-icing boots can produce rapidly spreading cracks and catastrophic failure; the AD aims to catch corrosion early and ensure blades are properly protected."}},"importantCases":[],"_links":{"self":"/api/acts/ad-phzl-54-hard-alloy-propeller-blades","history":"/api/acts/ad-phzl-54-hard-alloy-propeller-blades/history","analysis":"/api/acts/ad-phzl-54-hard-alloy-propeller-blades/analysis","conflicts":"/api/acts/ad-phzl-54-hard-alloy-propeller-blades/conflicts","importantCases":"/api/acts/ad-phzl-54-hard-alloy-propeller-blades/important-cases","documents":"/api/acts/ad-phzl-54-hard-alloy-propeller-blades/documents"}}