{"id":"F2006B06196","name":"AD/PHS/21 Amdt 1 - Blade Spar Taper Bore","slug":"ad-phs-21-amdt-1-blade-spar-taper-bore","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47067,"registerId":"commonwealth-F2006B06196-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PHS/21 Amdt 1 - Blade Spar Taper Bore","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 \\- Hamilton Standard\n\nAD/PHS/21\n\nAmdt 1\n\n  \nBlade Spar Taper Bore 8/96 DM\n\nApplicability: All model 14RF, 14SF, and 6/5500/F Series propellers with blade and pin assemblies with manufacturing serial number less than 885718.\n\nNote: These propellers are fitted to Embraer EMB-120, DHC-8-100 and 300, Aerospatiale ATR42, CASA CN-235, SAAB SF340, BAe ATP, and Canadair CL215T/CL415T Series aircraft.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 96-08-02 Amendment 39-9568. The ultrasonic shear wave inspections required by this Directive must be carried out by an appropriately qualified NDT Authority holder.\n\nNote 1: FAA AD 96-08-02 Amdt 39-9568 supersedes FAA AD 96-01-01 Amdt 39- 9477 which superseded FAA Telegraphic AD T95-18-51 and FAA Priority Letter AD 95-18-06R1.\n\nNote 2: Initial issue of this Directive cancelled AD/PHS/17 Amdt 2 and AD/PHS/19 Amdt 1.\n\nNote 3: All blade and pin assemblies previously inspected in accordance with AD/PHS/17 Amdt 2, AD/PHS/19 Amdt 1 or AD/PHS/21 are required to be re- inspected in accordance with this Directive.\n\nCompliance: Effective 29 May 1996; as detailed in the Requirement Document.\n\nBackground: A recent accident involving an Embraer EMB-120 aircraft has been attributed to fatigue cracking in the blade taper bore area which resulted in the liberation of a blade during flight. The initial Directive was issued to require an improved taper bore ultrasonic shear wave inspection and also to reduce various re-inspection intervals that are dependent on which aircraft propeller model is being inspected and provides an inspection to re-evaluate the serviceability of blade and pin assemblies previously rejected in accordance with AD/PHS/19 Amdt 1.\n\nAmendment 1 requires a blade repair that constitutes terminating action for the repetitive taper bore ultrasonic inspection requirement.\n\nThe initial issue of this Airworthiness Directive became effective on 27 February 1996.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 modifies the original Directive by adding a blade repair that serves as terminating action for the repetitive taper‑bore ultrasonic inspections ('Amendment 1 requires a blade repair that constitutes terminating action for the repetitive taper bore ultrasonic inspection requirement.'). The Directive also cancels earlier ADs and requires re‑inspection of assemblies previously inspected under those ADs ('Initial issue ... cancelled AD/PHS/17 Amdt 2 and AD/PHS/19 Amdt 1.'; 'All blade and pin assemblies previously inspected ... are required to be re‑inspected ...')."},"complexity_factors":["Cross-reference to an external FAA document: 'Action in accordance with the technical requirements of FAA AD 96-08-02 Amendment 39-9568.' (Requirement)","Narrow applicability requiring serial‑number checks: '...propellers with blade and pin assemblies with manufacturing serial number less than 885718.' (Applicability)","Mandatory specialist qualification for inspections: 'The ultrasonic shear wave inspections required by this Directive must be carried out by an appropriately qualified NDT Authority holder.' (Requirement)","Re‑inspection obligation for previously inspected assemblies: 'All blade and pin assemblies previously inspected ... are required to be re‑inspected in accordance with this Directive.' (Note 3)","Introduction of an alternative compliance path: 'Amendment 1 requires a blade repair that constitutes terminating action for the repetitive taper bore ultrasonic inspection requirement.' (Background)","Multiple affected aircraft types increase administrative reach: listed aircraft include EMB‑120, DHC‑8, ATR42, CN‑235, SF340, BAe ATP, CL215T/CL415T. (Note)"],"plain_english_summary":"**AD/PHS/21 Amdt 1 requires ultrasonic shear‑wave inspections of specified Hamilton Standard blade-and-pin assemblies (serials <885718) fitted to listed aircraft and mandates those inspections be carried out by a qualified NDT Authority.** It adds a blade repair option that, once performed, stops the need for repetitive taper-bore inspections. The Directive was prompted by fatigue cracking in the taper-bore area that caused a blade to separate in flight."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment stays tightly focused on its original safety purpose. Amendment 1 adds a terminating repair action to the existing inspection regime, which is a natural evolution of the original directive rather than scope creep. The document remains a targeted response to a specific mechanical failure mode in specific propeller models."},"complexity_factors":["Short, single-purpose document (approximately 300 words)","Only 3 defined applicability criteria (propeller models and serial number threshold)","Simple conditional structure: if your propeller matches the description, you must comply","Cross-references to external FAA documents but incorporates them by reference rather than reproducing complex technical standards","Clear compliance date and terminating action provision","Limited exception handling — primarily serial number cut-off and previous inspection history notes"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of certain Hamilton Standard propellers (specific models/serials) to have qualified NDT technicians perform shear‑wave ultrasonic inspections for fatigue cracking at the blade spar taper bore, after an EMB‑120 blade separation. Amendment 1 adds a specified blade repair as a terminating action to stop recurring inspections. Compliance has been mandatory since 29 May 1996."},"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-phs-21-amdt-1-blade-spar-taper-bore","history":"/api/acts/ad-phs-21-amdt-1-blade-spar-taper-bore/history","analysis":"/api/acts/ad-phs-21-amdt-1-blade-spar-taper-bore/analysis","conflicts":"/api/acts/ad-phs-21-amdt-1-blade-spar-taper-bore/conflicts","importantCases":"/api/acts/ad-phs-21-amdt-1-blade-spar-taper-bore/important-cases","documents":"/api/acts/ad-phs-21-amdt-1-blade-spar-taper-bore/documents"}}