{"id":"F2005L03922","name":"AD/PHZL/84 - Propeller Control Unit","slug":"ad-phzl-84-propeller-control-unit","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39739,"registerId":"commonwealth-F2005L03922-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Propellers - Variable Pitch - Hartzell","sectionType":"division","heading":"Propellers - Variable Pitch - Hartzell","content":"### Propellers - Variable Pitch - Hartzell\n\n| AD/PHZL/84 | Propeller Control Unit | 1/2006 |\n| ---------- | ---------------------- | ------ |\n\n```html\n

Applicability:

Hartzell Propeller Inc. model HD-E6C-3B/E13890K propellers with certain serial numbers of model D-1199-2 Propeller Control Units (PCU's) installed, as listed in Table 1 of this AD.

Note 1: These propellers are installed on, but not limited to Fairchild Dornier GmbH 328-100 series aeroplanes.

Requirement:

1. Perform an initial flight idle blade angle inspection, in accordance with paragraph 2A. of the Accomplishment Instructions of Hartzell Service Bulletin (SB) No. HD-SB-61-025, Revision 1, dated 20 December 2000 or later FAA approved revision on PCU’s listed by serial number in Table 1 of this AD.

Table 1.-Affected Serial Numbers, Model D-1199-2 PCU's

PCU-A-29

PCU-A-EFS140

PCU-A-EFS194

PCU-A-EFS234

PCU-A-EFS284

PCU-A-31

PCU-A-EFS141

PCU-A-EFS204

PCU-A-EFS236

PCU-A-EFS290

PCU-A-44

PCU-A-EFS144

PCU-A-EFS207

PCU-A-EFS239

PCU-A-EFS292

PCU-A-46

PCU-A-EFS152

PCU-A-EFS208

PCU-A-EFS242

PCU-A-EFS293

PCU-A-53

PCU-A-EFS155

PCU-A-EFS210

PCU-A-EFS244

PCU-A-EFS294

PCU-A-54

PCU-A-EFS158

PCU-A-EFS212

PCU-A-EFS245

PCU-A-EFS302

PCU-A-57

PCU-A-EFS160

PCU-A-EFS213

PCU-A-EFS246

PCU-A-EFS307

PCU-A-58

PCU-A-EFS162

PCU-A-EFS214

PCU-A-EFS249

PCU-A-EFS319

PCU-A-59

PCU-A-EFS165

PCU-A-EFS218

PCU-A-EFS250

PCU-A-EFS320

PCU-A-EFS101

PCU-A-EFS182

PCU-A-EFS220

PCU-A-EFS257

PCU-A-EFS326

PCU-A-EFS106

PCU-A-EFS184

PCU-A-EFS223

PCU-A-EFS261

PCU-A-EFS328

PCU-A-EFS109

PCU-A-EFS185

PCU-A-EFS224

PCU-A-EFS266

PCU-A-EFS330

PCU-A-EFS110

PCU-A-EFS187

PCU-A-EFS225

PCU-A-EFS268

PCU-A-EFS340

PCU-A-EFS111

PCU-A-EFS188

PCU-A-EFS226

PCU-A-EFS269

PCU-A-EFS347

PCU-A-EFS120

PCU-A-EFS192

PCU-A-EFS228

PCU-A-EFS271

\"\"

PCU-A-EFS122

PCU-A-EFS193

PCU-A-EFS233

PCU-A-EFS279

\"\"

2. Remove PCU's that fail the inspection per requirement 1 of this AD and perform a Major Periodic Inspection (overhaul), in accordance with paragraphs 2.B. and 2.C. of the Accomplishment Instructions of Hartzell SB No. HD-SB-61-025, Revision 1 or later FAA approved revision, or replace with a serviceable PCU.

3. Perform the flight idle blade angle inspection until the limiting time-since-overhaul or time-since-new is reached, as specified in Hartzell SB
HD-SB-61-025, Revision 1 or later FAA approved revisions.

4. Remove PCU's that fail the inspection per requirement 3 of this AD and perform a Major Periodic Inspection (overhaul), in accordance with paragraphs 2.B. and 2.C. of Hartzell SB No. HD-SB-61-025, Revision 1 or later FAA approved revision, or replace with a serviceable PCU.

5. Remove the PCU from service and perform a Major Periodic Inspection (overhaul), in accordance with paragraphs 2.B. and 2.C. of Hartzell SB
HD-SB-61-025, Revision 1 or later FAA approved revisions.

Optional Terminating Action

Replacement with a serviceable PCU is terminating action for the repetitive inspections specified in requirement 3 of this AD. For the purpose of this AD, a serviceable PCU is one that is not listed in Table 1 of this AD, or is one listed in Table 1 of this AD that has undergone a Major Periodic Inspection (overhaul) after
17 November 2000, in accordance with paragraphs 2.B. and 2.C. of Hartzell SB
HD-SB-61-025, Revision 1 or later FAA approved revisions.

Note 2: FAA AD 2003-04-22 Amdt 39-13071 refers.

Compliance:

1 and 2. At the next \"2A\" maintenance check, but no later than 600 hours time-in-service from the effective date of this AD.

3 and 4. At each successive \"4A\" maintenance check, but not to exceed 1,200 hours time-in-service.

5. Once the limiting time-since-overhaul or time-since-new specified in Hartzell SB HD-SB-61-025, Revision 1 or later FAA approved revision is reached.

This Airworthiness Directive becomes effective on 19 January 2006.

\n```\n\n| Background: | This AD is prompted by a review by Hartzell Propeller Inc. of the model D-1199-2 PCU overhaul procedures, that revealed several dimensional checks and a non-destructive evaluation were not performed on certain serial number PCU's during a Major Periodic Inspection (overhaul). The overhaul procedures are required to comply with the Airworthiness Limitation PCU Major Periodic Inspection (overhaul) directive. The actions specified by this AD are intended to prevent below-limit flight idle propeller blade angles that, if not corrected, could result in degraded aircraft performance and control. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.003.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n30 November 2005","sortOrder":0},{"sectionNumber":"AD/PHZL/84","sectionType":"part","heading":"AD/PHZL/84","content":"## AD/PHZL/84","sortOrder":1},{"sectionNumber":"Propeller Control Unit","sectionType":"part","heading":"Propeller Control Unit","content":"## Propeller Control Unit","sortOrder":2},{"sectionNumber":"1/2006","sectionType":"part","heading":"1/2006","content":"## 1/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive confines obligations to the PCU model and serial numbers listed in Table 1 and requires work to the SB procedures; it does not broaden applicability beyond those units or add new components. Therefore the practical scope remains aligned with the stated safety review that identified omitted overhaul checks."},"complexity_factors":["Technical maintenance requirements (flight idle blade angle inspection, Major Periodic Inspection/overhaul) referencing specific procedures in Hartzell SB HD-SB-61-025","Long list of affected PCU serial numbers (Table 1) requiring identification and tracking by operators","Cross-reference to FAA‑approved revisions and FAA AD 2003-04-22, creating dependence on external approvals","Specified compliance windows tied to maintenance checks (\"2A\" and \"4A\") and hour limits (600 h, 1,200 h) that operators must map to their maintenance schedules","Optional terminating action (replacement with a serviceable PCU) and a specific definition of \"serviceable\" linked to overhaul date","Enforcement relies on maintenance recordkeeping and correct application of overhaul procedures, increasing administrative burden"],"plain_english_summary":"Mandates inspections and, where necessary, overhaul or replacement of specific Hartzell D-1199-2 Propeller Control Units (PCUs) listed in Table 1, using the procedures in Hartzell Service Bulletin HD-SB-61-025 (or later FAA‑approved revisions). Operators of affected propellers (for example, those on Dornier 328‑100 series aircraft) must perform an initial flight idle blade angle check, repeat periodic checks at defined maintenance intervals, and remove any PCU that fails for Major Periodic Inspection or replacement. The AD responds to missing overhaul checks that could allow below‑limit idle blade angles and reduced aircraft control."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope focused specifically on Hartzell D-1199-2 PCUs with identified serial numbers. The document represents a targeted safety intervention for a defined hardware defect, consistent with standard airworthiness directive practice. No evidence of scope creep beyond the original safety purpose."},"complexity_factors":["Single, specific technical subject matter (propeller control units) with narrow applicability","Clear numbered requirements (1-5) with straightforward conditional logic (if fail inspection, then overhaul/replace)","Extensive tabular data (70 specific serial numbers) but presented in a simple lookup format","External cross-reference to manufacturer service bulletin (Hartzell SB HD-SB-61-025) for technical procedures","Defined compliance timelines using standard aviation maintenance intervals ('2A' and '4A' checks, flight hours)","No nested exceptions or complex definitional sections — terminology is industry-standard aviation language","Optional terminating action clearly specified (replacement with serviceable PCU ends inspection requirements)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) that requires specific maintenance actions on aircraft.\n\n**What it does:**\nThis directive orders owners and operators of certain Hartzell propellers to inspect and potentially overhaul or replace specific Propeller Control Units (PCUs). A PCU is the device that adjusts the angle of the propeller blades during flight.\n\n**Who it affects:**\n- Aircraft fitted with **Hartzell Propeller Inc. model HD-E6C-3B/E13890K propellers** that have specific **Model D-1199-2 PCUs** with serial numbers listed in Table 1 (about 70 specific units)\n- These propellers are commonly found on **Fairchild Dornier 328-100 series aircraft**\n\n**Why it matters:**\nThe manufacturer discovered that during previous overhauls, some PCUs missed critical dimensional checks and safety inspections. This could cause the propeller blades to sit at the wrong angle when the engine is at idle (\"flight idle blade angle\"). If uncorrected, this could reduce aircraft performance and make the plane harder to control — potentially creating a safety risk during flight.\n\n**What must be done:**\n1. **Initial inspection:** Check the flight idle blade angle at the next scheduled maintenance check, but within 600 flight hours\n2. **If it fails:** Remove the PCU for a full overhaul or replace it with a serviceable unit\n3. **Ongoing checks:** Repeat the inspection every 1,200 flight hours until the unit reaches its maximum allowed service life\n4. **Final removal:** Once the PCU hits its time limit, it must be overhauled or replaced regardless of condition\n\n**Key date:** The directive took effect on **19 January 2006**."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-phzl-84-propeller-control-unit","history":"/api/acts/ad-phzl-84-propeller-control-unit/history","analysis":"/api/acts/ad-phzl-84-propeller-control-unit/analysis","conflicts":"/api/acts/ad-phzl-84-propeller-control-unit/conflicts","importantCases":"/api/acts/ad-phzl-84-propeller-control-unit/important-cases","documents":"/api/acts/ad-phzl-84-propeller-control-unit/documents"}}