{"id":"F2010L02440","name":"AD/PW4000/16 - Front Pylon Mount Bolts","slug":"ad-pw4000-16-front-pylon-mount-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":84370,"registerId":"commonwealth-F2010L02440-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Pratt and Whitney Turbine Engines - PW40","sectionType":"division","heading":"Pratt and Whitney Turbine Engines - PW4000 Series","content":"### Pratt and Whitney Turbine Engines - PW4000 Series\n\n| AD/PW4000/16 | Front Pylon Mount Bolts | 18/2010 |\n| ------------ | ----------------------- | ------- |\n\n| Applicability: | Pratt & Whitney (PW) PW4164, PW4168, and PW4168A series turbofan engines, with front pylon mount bolts, part number (P/N) 54T670 or 51U615, installed. These engines are installed on, but not limited to, Airbus A330 series airplanes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Unless previously accomplished, perform the initial torque checks and inspections in accordance with the technical requirements of FAA AD 2006-16-05 Amendment39-14705.Repeat the torque checks and inspections in accordance with the technical requirements of FAA AD 2006-16-05 Amendment 39-14705.Replacement of the forward engine mount bearing housing, P/N 59T794 or P/N 54T659 with P/N 52U420, using SB PW4G-100-71-22, dated 15 January 2002, or later FAA approved revision, constitutes terminating action to the inspection requirements of paragraph (h) of the requirement document, FAA AD 2006-16-05 Amendment 39-14705.Later revisions to PW ASB PW4G-100-A71-9, Revision 1, dated 24 November 1997, PW ASB PW4G-100-A71-18, Revision 2, dated 15 January 2002, and PW ASB PW4G-100-A71-32, dated 15 April 2005, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2006-16-05 Amendment 39-14705, are considered acceptable for compliance with the equivalent Requirements of this AD. |\n| Compliance:    | As specified in the Requirement Document with a revised effective date of13 September 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | This Airworthiness Directive becomes effective on 13 September 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n\n| Background: | This AD results from analysis by the manufacturer that MP159 material pylon bolts do not meet the full life cycle torque check interval requirement, in a bolt-out condition. This AD is issued to prevent front pylon mount bolt and primary mount thrust load path failure, which could result in an engine separating from the airplane. |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)\n\nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n9 September 2010","sortOrder":0},{"sectionNumber":"AD/PW4000/16","sectionType":"part","heading":"AD/PW4000/16","content":"## AD/PW4000/16","sortOrder":1},{"sectionNumber":"Front Pylon Mount Bolts","sectionType":"part","heading":"Front Pylon Mount Bolts","content":"## Front Pylon Mount Bolts","sortOrder":2},{"sectionNumber":"18/2010","sectionType":"part","heading":"18/2010","content":"## 18/2010","sortOrder":3}],"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"},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a focused, narrow scope. It addresses a specific mechanical defect in specific engine models. The directive maintains its original purpose of preventing engine separation due to bolt failure. The incorporation of FAA requirements and service bulletin references is standard practice for aviation safety regulation and does not represent scope creep."},"complexity_factors":["Heavy reliance on external documents: The directive references FAA AD 2006-16-05 and multiple Pratt & Whitney Service Bulletins (SB PW4G-100-71-22, PW ASB PW4G-100-A71-9, etc.) without reproducing their full text","Nested part number references: Multiple specific part numbers (54T670, 51U615, 59T794, 54T659, 52U420) must be cross-referenced to determine applicability","Conditional compliance paths: Different requirements apply depending on whether terminating action (replacement) has been performed","AMOC (Alternate Method of Compliance) provisions allow for alternative approved procedures, creating conditional compliance pathways","Dual regulatory framework: Australian operators must comply with US FAA technical requirements, creating a layered compliance structure"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of aircraft with Pratt & Whitney PW4164/4168/4168A engines (notably Airbus A330s) to inspect and retorque front pylon mount bolts (PN 54T670/51U615) because affected MP159 material bolts can lose preload, risking engine separation. It mandates initial and repetitive torque checks and ultimately replacing a bearing housing as a terminating action. The AD adopts corresponding FAA requirements for compliance."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The instrument enforces FAA AD 2006-16-05 requirements for specified PW4000 engines and bolts and adds an explicit terminating action via a particular bearing-housing replacement and accepted ASB revisions. It does not materially expand the safety objective beyond preventing front pylon mount bolt/primary mount thrust-path failure, though its ‘not limited to’ fleet wording broadens the practical set of affected aircraft models."},"complexity_factors":["Technical specificity of applicability: exact engine models and bolt part numbers (Applicability).","Cross-reference to external instrument: requires compliance with FAA AD 2006-16-05, shifting readers to a separate document for procedures (Requirement).","Multiple acceptable compliance routes: recurring inspections or a specified replacement as terminating action, plus acceptance of later ASB revisions as AMOCs (Requirement).","Operational impact: recurring torque checks and inspections impose maintenance scheduling, labour, downtime and parts costs on operators (Requirement; Compliance).","Material/engineering basis: safety rationale tied to MP159 bolt material life-cycle behaviour, requiring technical judgement about bolt-out conditions (Background).","Potential ambiguity in fleet scope: wording 'installed on, but not limited to, Airbus A330' widens applicability beyond a single airframe and may complicate operator identification (Applicability).","Regulatory interaction: CASA instrument implements FAA requirements and defers AMOC approvals to FAA-accepted revisions, creating multi-jurisdictional compliance checks (Requirement)."],"plain_english_summary":"This Airworthiness Directive requires operators of Pratt & Whitney PW4164/PW4168/PW4168A engines fitted with front pylon mount bolts P/N 54T670 or 51U615 to do initial and recurring torque checks and inspections per FAA AD 2006-16-05, unless they replace the forward engine mount bearing housing with P/N 52U420 using the specified service bulletin as a terminating action. It affects airlines and maintenance organisations, who pay for inspections, parts and associated downtime; compliance methods and any AMOCs are decided by the regulator (FAA/CASA)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pw4000-16-front-pylon-mount-bolts","history":"/api/acts/ad-pw4000-16-front-pylon-mount-bolts/history","analysis":"/api/acts/ad-pw4000-16-front-pylon-mount-bolts/analysis","conflicts":"/api/acts/ad-pw4000-16-front-pylon-mount-bolts/conflicts","importantCases":"/api/acts/ad-pw4000-16-front-pylon-mount-bolts/important-cases","documents":"/api/acts/ad-pw4000-16-front-pylon-mount-bolts/documents"}}