{"id":"F2014L01324","name":"AD/PHS/18 Amdt 4 - Hub Cracking","slug":"ad-phs-18-amdt-4-hub-cracking","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":92312,"registerId":"commonwealth-F2014L01324-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Propellers - Variable Pitch - Hamilton S","sectionType":"division","heading":"Propellers - Variable Pitch - Hamilton Standard","content":"### Propellers - Variable Pitch - Hamilton Standard\n\n| AD/PHS/18 Amdt 4 | Hub Cracking | 20/2014 |\n| ---------------- | ------------ | ------- |\n\n| Applicability: | All model 14RF-9, 14RF-19 and 14RF-21 propellers.Note 1: These propellers may be installed on but are not limited to EmbraerEMB-120 series, CASA CN-235 series and SAAB SF-340 series aircraft.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. (a) Perform a torque check of the propeller hub retaining nuts, in accordance with the applicable Hamilton Sundstrand Maintenance Manual (MM).(b) Remove from service propellers where the hub retaining nuts are found not to meet the acceptance criteria outlined in the applicable Hamilton Sundstrand MM.(c) Inspect hub dowel pin holes for cracks in accordance with the applicable Hamilton Sundstrand MM using the prescribed fluorescent penetrant inspection method.(d) Remove from service propeller hubs with crack indications.(e) If the initial propeller hub retaining nut torque check per requirement 1.(a) is acceptable in accordance with the applicable Hamilton Sundstrand MM, support the propeller with an appropriate lifting fixture and loosen the propeller hub retaining nuts. Tighten the propeller hub retaining nuts as detailed in the applicable Hamilton Sundstrand MM.(f) Make a one-time entry in the propeller maintenance records to record:(i) that the initial torque check was performed;(ii) the propeller hub retaining nuts were loosened and tightened in accordance with Requirement 1.(e) of this Directive; and(iii) the torque values.2. Repeat requirement 1.(a) up to and including 1.(d) of this Directive. |\n\n|             | 3. Install all propellers using the propeller hub retaining nut tightening procedure defined in the applicable Hamilton Sundstrand MM. Record the torque values in accordance with Requirement 1.(f) (iii) of this Directive.4. (a) Visually inspect for and investigate all external propeller oil leakage.(b) If the leakage is found to be caused by other than a leak in the blade seal, the pressure relief valve, or actuator assembly, remove the propeller from service.Note 3: FAA AD 94-06-05 Amdt 39-8853 refers.                                                                                                                                                                                                                    |\n| ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. (a) Unless previously accomplished in accordance with the original issue or amendment 1, 2 or 3 of this Directive, within 30 days from the effective date of this Directive.(b) Before further flight, based on Requirement 1.(a) findings.(c) Concurrently with Requirement 1.(b).(d) Before further flight, based on Requirement 1.(c) findings.(e) Before further flight following completion of initial torque check per requirement 1.(a).(f) Following completion of Requirement 1.(a) and 1.(e) of this Directive.2. At intervals not to exceed 500 flight hours.3. From the effective date of this Directive.4. (a) At intervals not to exceed 70 flight hours.(b) Before further flight after the effective date of this Directive. |\n|             | The effective date of this AD is 7 October 2014.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n| Background: | This Directive was originally issued to address manufacturer’s torqueing procedures for the propeller hub retaining nuts, which was insufficient to prevent fretting during normal propeller operation. If allowed to continue, cracking of the propeller hub may occur.AD/PHS/18 Amdt 1, which became effective on 27 November 2003, removed references to manufacturers’ temporary revision and instead referred to the manufacturers publications that incorporate the correct values and procedures for torqueing the propeller hub retaining nuts.                                                                                                                                                                                         |\n\n|     | AD/PHS/18 Amdt 2, which became effective on 9 June 2005, corrected errors in Amendment 1 of the Directive with no change to the intent of the Directive.AD/PHS/18 Amdt 3, which became effective on 22 November 2007, clarified the loosening of the propeller hub retaining nuts and recording of the torque values in the propeller maintenance records (which only has to be done initially and when a propeller is installed to the aircraft) and brings the oil leakage inspection interval in line with FAA AD 94-06-05.This AD, AD/PHS/18 Amdt 4, clarifies the requirement of the non-destructive inspection method and makes minor editorial changes throughout the text. |\n| --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)\n\nMike Higgins  \nDelegate of the Civil Aviation Safety Authority\n\n30 September 2014","sortOrder":0},{"sectionNumber":"AD/PHS/18 Amdt 4","sectionType":"part","heading":"AD/PHS/18 Amdt 4","content":"## AD/PHS/18 Amdt 4","sortOrder":1},{"sectionNumber":"Hub Cracking","sectionType":"part","heading":"Hub Cracking","content":"## Hub Cracking","sortOrder":2},{"sectionNumber":"20/2014","sectionType":"part","heading":"20/2014","content":"## 20/2014","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is Amendment 4 of an existing Airworthiness Directive. The amendments have remained tightly focused on the original safety issue: preventing propeller hub cracking through proper torque procedures and inspection. While the text has been refined across four amendments (clarifying inspection methods, correcting errors, aligning with FAA directives), the fundamental scope — addressing hub nut torque and cracking in Hamilton Standard 14RF series propellers — has not expanded beyond the original safety intent."},"complexity_factors":["Multiple nested requirements with sub-subsections (1.(a) through 1.(f)(iii))","Cross-references to external manufacturer maintenance manuals (Hamilton Sundstrand MM) without reproducing the actual procedures","Conditional compliance timelines that vary based on previous actions ('Unless previously accomplished...')","Multiple compliance intervals (30 days, 500 flight hours, 70 flight hours, 'before further flight')","Reference to foreign aviation authority documentation (FAA AD 94-06-05)","Four previous amendments creating layered history that must be understood for full context"],"plain_english_summary":"This AD orders mandatory inspections and maintenance for Hamilton Standard 14RF‑9/19/21 propellers used on EMB‑120, CN‑235, and SAAB SF‑340 aircraft after nut fretting was found. Operators must torque‑check and retorque hub nuts per the manual, perform dye‑penetrant crack inspections around dowel holes, remove any nonconforming propellers from service, and carry out recurring torque and oil‑leak checks. The goal is to prevent propeller‑hub cracking and catastrophic in‑flight separation."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"Amendment 4 clarifies the prescribed non‑destructive inspection method and makes editorial changes without expanding the set of affected propeller models or adding new categories of obligation. Earlier amendments corrected references to manufacturer publications, clarified record‑keeping and inspection intervals, but did not broaden applicability or create new regulatory policy (Background)."},"complexity_factors":["Multiple distinct technical actions required: initial torque check, fluorescent‑penetrant non‑destructive inspection (NDI), loosening/re‑torquing procedure, oil‑leak visual checks, and removal from service where defects found (Requirement 1(a)–(f); 3; 4).","Staggered compliance timings and recurring intervals (initial 30 days; repeat every 500 flight hours; oil leakage check every 70 flight hours; before‑flight triggers) create operational scheduling complexity (Compliance).","Substantial reliance on an external document (Hamilton Sundstrand Maintenance Manual) for acceptance criteria, procedures and torque values increases dependency on manufacturer material and creates cross‑reference risk (Requirements reference MM).","Record‑keeping obligation (one‑time and installation entries recording torque values and actions) imposes administrative burden on maintainers (Requirement 1(f)).","Clear removal‑from‑service criteria for cracked hubs or unacceptable leakage require potentially grounding propellers/aircraft and incur direct replacement/repair costs (Requirements 1(b),(d) and 4(b)).","Applicability is limited to specific propeller models but those models are installed on multiple aircraft types, widening operational impact across fleets (Applicability).","Cross‑reference to earlier ADs and FAA AD introduces legal/technical history to interpret intent; Amdt 4 mainly clarifies inspection method and edits rather than changing core obligations (Background)."],"plain_english_summary":"This airworthiness directive requires operators of Hamilton Standard variable‑pitch propellers (models 14RF‑9, 14RF‑19 and 14RF‑21) to carry out torque checks, a prescribed fluorescent‑penetrant inspection of hub dowel pin holes, re‑torque procedures per the Hamilton Sundstrand Maintenance Manual, record torque values, and remove cracked or improperly sealing hubs from service. It is designed to prevent fretting that can lead to hub cracking. Operators and maintenance organisations bear the inspection, repair and record‑keeping costs; CASA enforces the deadlines and recurring inspection intervals."}},"importantCases":[],"_links":{"self":"/api/acts/ad-phs-18-amdt-4-hub-cracking","history":"/api/acts/ad-phs-18-amdt-4-hub-cracking/history","analysis":"/api/acts/ad-phs-18-amdt-4-hub-cracking/analysis","conflicts":"/api/acts/ad-phs-18-amdt-4-hub-cracking/conflicts","importantCases":"/api/acts/ad-phs-18-amdt-4-hub-cracking/important-cases","documents":"/api/acts/ad-phs-18-amdt-4-hub-cracking/documents"}}