{"id":"F2006B03115","name":"AD/B747/215 - Engine Thrust Links PW4000 Powered Aircraft","slug":"ad-b747-215-engine-thrust-links-pw4000-powered-aircraft","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42487,"registerId":"commonwealth-F2006B03115-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/215 - Engine Thrust Links PW4000 Powered Aircraft","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/215 Engine Thrust Links PW4000 Powered Aircraft\n\n  \n12/99\n\nApplicability: Boeing 747-400 series aircraft powered by Pratt and Whitney PW4000 series engines.\n\nRequirement: 1. For Group 1 aircraft, as identified in Boeing Alert Service Bulletin 747-71A2283, carry out a detailed visual inspection of the engine thrust link components in accordance with the alert service bulletin, Work Package 1.\n\nRectify any discrepancy or damage found during this inspection prior to further flight.\n\n    2. For Group 1 aircraft, replace the existing end cap and end cap bolts of the forward engine mount end cap assembly with improved end cap and end cap bolts in accordance with Boeing Alert Service Bulletin 747-71A2283, Work Package 2.\n\nCompliance with Requirement 2 constitutes terminating action for this airworthiness directive for Group 1 aircraft.\n\n    3. For Group 2 aircraft, replace the existing end cap bolts with improved end cap bolts in accordance with Boeing Alert Service Bulletin 747-71A2283, Work Package 3.\n\n    4. End cap, P/No 310T3026-1 shall not be installed as a replacement part on Australian registered Boeing 747 aircraft.\n\nNote: FAA AD 99-11-12 refers.\n\nCompliance: 1. Unless previously accomplished, carry out an initial inspection within 500 hours time in service after the effective date of this airworthiness directive.\n\nThereafter, re-inspect at intervals not to exceed 5000 hours time in service or 15 months whichever occurs first.\n\n    2. (a) Prior to accumulating 16,000 flight cycles on any engine or within 500 hours time in service after the effective date of this airworthiness directive whichever occurs later, but no later than three years after the effective date of this airworthiness directive.\n\n(b) Prior to further flight if rectification of any damage or discrepancy is required as a result of the inspection per Requirement 1.\n\n    3. No later than three years after the effective date of this airworthiness directive.\n\n    4. As of the effective date of this airworthiness directive.\n\nThis Airworthiness Directive becomes effective on 2 December 1999.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nBackground: This AD is prompted by reports of forward engine mount end cap bolt fatigue failures. End cap bolt failure could result in failure of the end cap assembly which, in the event of a primary thrust link failure, could lead to separation of an engine from the aircraft.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This airworthiness directive maintains its original narrow scope: addressing a specific mechanical defect (fatigue failures in engine mount end cap bolts) on a specific aircraft/engine combination (Boeing 747-400 with PW4000 engines). The requirements remain tightly focused on inspection and replacement of the identified components."},"complexity_factors":["Multiple compliance deadlines with conditional logic ('whichever occurs first/last')","Aircraft divided into two groups (Group 1 and Group 2) with different requirements","Cross-reference to external Boeing Alert Service Bulletin (747-71A2283) and FAA AD 99-11-12","Specific part number prohibition (P/No 310T3026-1)","Terminating action clause (Requirement 2 ends the need for ongoing inspections for Group 1)","Nested conditions in Compliance section 2(a): three different deadline calculations"],"plain_english_summary":"This CASA safety order targets Boeing 747‑400s with Pratt & Whitney PW4000 engines, requiring inspections and replacement of engine‑mount bolts and end‑caps after metal‑fatigue cracks were found. It affects Australian operators and maintenance crews, bans part 310T3026‑1 from installation, and sets staged compliance deadlines (from 500 flight hours up to three years) to prevent possible in‑flight engine separation."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive stays within the original safety-focused scope: detect and eliminate fatigued forward engine mount end cap bolts to prevent end cap failure and potential engine separation. It does not expand regulatory reach beyond inspections, mandated replacements, and a part prohibition tied directly to that safety hazard. The AD also aligns with the FAA action and uses Boeing’s service bulletin for technical implementation, rather than adding unrelated regulatory requirements."},"complexity_factors":["Multiple action categories (Requirements 1–4) with different obligations","Two aircraft groups (Group 1 and Group 2) with different required actions","Cross-reference to an external Boeing Alert Service Bulletin (Work Packages 1–3) for procedural detail","Multiple conditional compliance triggers (hours in service, flight cycles, and fixed calendar maximum of three years) and \"whichever occurs later/earlier\" phrasing","A terminating action for Group 1 that removes a recurring inspection obligation once completed","A parts prohibition (specific part number banned) adding a supply/parts-control element","Reference to an FAA AD for related context"],"plain_english_summary":"**What this directive does (mechanically)**\n\n- Applies to Boeing 747-400 series aeroplanes that use Pratt & Whitney PW4000 engines.\n- Requires operators of affected aircraft to inspect the forward engine thrust link components (detailed visual inspection) and to repair any damage found before further flight (Requirement 1).\n- Requires replacement of the forward engine mount end cap and its bolts with improved parts for Group 1 aircraft (Requirement 2). Completing that replacement is a \"terminating action\" for the inspection requirement for Group 1 aircraft (i.e. once replaced, the recurring inspection obligation for that group ends).\n- Requires replacement of the end cap bolts with improved bolts for Group 2 aircraft (Requirement 3).\n- Prohibits installing end cap part number 310T3026-1 on Australian-registered Boeing 747 aircraft (Requirement 4).\n- The directive references Boeing Alert Service Bulletin 747-71A2283 and its Work Packages 1–3 for the inspection and replacement procedures.\n\n**When the work must be done (summary of compliance timings)**\n\n- Initial inspection: within 500 flight hours after the AD’s effective date (unless already done). Re-inspect thereafter every 5,000 flight hours or every 15 months, whichever comes first (Requirement 1 compliance).\n- For Group 1 replacement (end cap + bolts): do so before any engine accumulates 16,000 flight cycles or within 500 flight hours after the AD becomes effective, whichever is later — but in any case no later than three years after the AD’s effective date. Also replace before further flight if the inspection finds damage (Requirement 2).\n- For Group 2 replacement (bolts only): replace within three years after the AD’s effective date (Requirement 3).\n- The banned part (P/No 310T3026-1) must not be used as of the AD’s effective date (Requirement 4).\n\n**Why the regulator says this is necessary (stated rationale)**\n\n- The AD was prompted by reports of fatigue failures of forward engine mount end cap bolts. A bolt failure could let the end cap assembly fail and, if a primary thrust link also failed, could lead to an engine separating from the aircraft. The AD cites the FAA Airworthiness Directive 99-11-12 for related action.\n\n**Who pays, who decides, and what behaviour changes**\n\n- Who pays: Aircraft operators (owners) must bear the costs — inspections, parts, certified maintenance labour, and aircraft downtime.\n- Who decides: The Civil Aviation Safety Authority (CASA) mandates the AD; operators must follow the detailed Boeing Service Bulletin procedures referenced for how to perform work. Maintenance providers execute the inspections and replacements under existing certification rules.\n- Behaviour changes required: Operators must add the initial and recurring inspection tasks to maintenance schedules, source improved end cap and bolt parts, and ensure the banned part is not installed. If damage is found, they must ground the aircraft until repairs are made.\n\n**Operational and economic implications / trade‑offs**\n\n- Costs and downtime: Replacing end caps and bolts requires parts and labour and may take aircraft out of service; inspections add recurring maintenance hours. These are direct, concentrated costs on operators of affected 747‑400 PW4000 aircraft.\n- Safety benefit vs cost: The stated safety benefit is prevention of catastrophic failure (engine separation) by removing a known weak part and by earlier detection of damage. That benefit is large per event but applies only to operators of the affected fleet.\n- Supply and implementation risk: The AD depends on availability of the \"improved\" parts specified in Boeing’s Service Bulletin. If parts are scarce, operators could face scheduling delays or higher costs. Certified maintenance capability and correct recordkeeping are also necessary to show compliance.\n- Compliance complexity: Actions are split by aircraft Group (Group 1 vs Group 2), and there are staggered compliance timelines and a terminating action for Group 1 — this requires operators to track group status, cycles, and hours to meet the right deadlines.\n- Market effects: The directive increases demand for the improved end cap/bolt parts and for maintenance shop capacity. It imposes a private compliance cost on operators but does not change ownership, operating rules, or market entry directly.\n\n**Source claims vs practical considerations**\n\n- The document claims bolt fatigue failures prompted the measure. Mechanically, the AD reduces the chance of bolt-induced end cap failure by requiring inspections and by mandating replacement with an improved design (the AD’s Requirements 1–3 and the prohibition in Requirement 4).\n- The practical costs are borne by operators (parts, labour, downtime). The AD imposes recurring inspection burden until terminating replacements are completed (for Group 1) or until replacements occur (for Group 2).\n\n**Reference linkage and harmonisation**\n\n- The AD uses Boeing Alert Service Bulletin 747-71A2283 for technical work instructions and cross‑references FAA AD 99‑11‑12, indicating regulatory harmonisation and reliance on the manufacturer’s corrective procedures.\n\n"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-215-engine-thrust-links-pw4000-powered-aircraft","history":"/api/acts/ad-b747-215-engine-thrust-links-pw4000-powered-aircraft/history","analysis":"/api/acts/ad-b747-215-engine-thrust-links-pw4000-powered-aircraft/analysis","conflicts":"/api/acts/ad-b747-215-engine-thrust-links-pw4000-powered-aircraft/conflicts","importantCases":"/api/acts/ad-b747-215-engine-thrust-links-pw4000-powered-aircraft/important-cases","documents":"/api/acts/ad-b747-215-engine-thrust-links-pw4000-powered-aircraft/documents"}}