{"id":"F2006B08454","name":"AD/CF34/7 - No.5 Bearing Rotating Air Seal","slug":"ad-cf34-7-no-5-bearing-rotating-air-seal","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51087,"registerId":"commonwealth-F2006B08454-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/CF34/7 No.5 Bearing Rotating Air Seal","sectionType":"part","heading":"AD/CF34/7 No.5 Bearing Rotating Air Seal 10/2001","content":"# ![](image.003.png)AD/CF34/7 No.5 Bearing Rotating Air Seal 10/2001\n\nDM\n\nApplicability: CF34-1A, \\-3A, \\-3A1, \\-3A2, \\-3B and \\-3B1 engines incorporating No.5 bearing rotating air seal, P/No.4019T60G01.\n\nRequirement: 1. Inspect the magnetic chip detector indicators. If chip detection is indicated, remove and visually inspect the chip detector. If debris is found comply with the requirements of the engine maintenance manual.\n\n2. Replace the No.5 bearing rotating air seal, P/No.4019T60G01, with air seal, P/No 4019T60G03.\n\nInstallation of air seal, P/No.4019T60G03 constitutes terminating action for the chip detector inspections in Requirement 1.\n\nNote: FAA AD 2001-12-06 refers.\n\nCompliance: 1. (a) For CF34-3A1, -3B1 and -3B engines, unless previously accomplished, carry out an initial check within 30 flight hours or 3 calendar days from the effective date of this Airworthiness Directive, whichever occurs later, and thereafter at intervals not to exceed 30 flight hours or 3 calendar days whichever is the greater.\n\nInspection of the magnetic chip detector indicators may be performed by a pilot endorsed on the aircraft type provided a system is in place to direct the pilot when the inspection is due, the pilot signs for performing the inspection and maintenance staff are advised to complete Requirement 1 if a chip detection is indicated.\n\n(b) For CF34-1A,-3A and \\-3A2 engines, unless previously accomplished, carry out an initial check within 100 flight hours from the effective date of this Airworthiness Directive and thereafter at intervals not to exceed 100 flight hours.\n\n2. (a) For CF34-3A1, \\-3B1 and \\-3B engines, replace the air seal at the next shop visit where the HPT is exposed, but not to exceed 15,000 cycles in service from the effective date of this Airworthiness Directive.","sortOrder":1}],"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":3,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with a focused, narrow scope. It addresses a specific unsafe condition in a specific engine part across specific engine models. The structure follows the standard CASA AD format (Applicability, Requirement, Compliance) without expansion beyond the original safety purpose."},"complexity_factors":["Multiple engine model variants with different compliance schedules (two distinct groups with different flight hour intervals)","Cross-reference to FAA AD 2001-12-06 (external US aviation safety document)","Conditional logic: 'unless previously accomplished' clauses","Dual-path compliance: ongoing inspections vs. terminating action through part replacement","Specific part numbers referenced (P/No.4019T60G01 and P/No.4019T60G03)","Pilot-performed maintenance provision with specific procedural conditions (system in place, sign-off, maintenance staff notification)","Time-based compliance using two different metrics (flight hours vs. calendar days vs. cycles) depending on engine model and action type"],"plain_english_summary":"This safety order targets CF34 engines fitted with the No.5 bearing rotating air seal (P/N 4019T60G01), which can shed metal debris detectable by magnetic chip detectors. It requires frequent chip-detector inspections (as often as every 30 flight hours or 3 days for some models, or every 100 flight hours for others) until the seal is replaced with the improved P/N 4019T60G03—typically within 15,000 flight cycles or at the next major overhaul. It affects operators of regional jets and business aircraft using these CF34 variants and prevents debris-induced engine failures."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive remains narrowly focused on correcting an unsafe condition related to the No.5 bearing rotating air seal on specified CF34 engines. It mandates inspection until replacement and prescribes a particular replacement part as terminating action. It does not broaden into unrelated regulatory areas or add new categories of regulated equipment beyond the stated engine models and part numbers."},"complexity_factors":["Applicability covers six CF34 variants (CF34-1A, -3A, -3A1, -3A2, -3B, -3B1)","Two substantive mandatory actions (Requirement 1: inspections; Requirement 2: part replacement)","Variant-specific compliance intervals (30 flight hours/3 days for some models; 100 flight hours for others)","Terminating action (installation of P/No.4019T60G03 stops recurring inspections)","Pilot-performed inspection permission for a subset of variants, with procedural conditions","A shop-visit/cycle limit for replacement for some variants (replace at next HPT exposure but no later than 15,000 cycles)","Reference to an external FAA AD (cross-regulatory cross-reference)","Minor textual ambiguity between initial timing phrasing ('whichever occurs later') and recurring interval phrasing ('whichever is the greater')"],"plain_english_summary":"**What this Directive does (mechanical change)\n\n- Requires operators of certain General Electric CF34 turbofan engines to inspect the magnetic chip detector indicators for metal debris and, if debris is found, to follow engine maintenance manual instructions. (Requirement 1)\n- Requires replacement of a specific No.5 bearing rotating air seal (part number 4019T60G01) with a redesigned air seal (part number 4019T60G03). Installing the new part stops (terminates) the recurring chip-detector inspections called for in Requirement 1. (Requirement 2)\n\nWhich engines are affected\n\n- The AD applies to CF34-1A, -3A, -3A1, -3A2, -3B and -3B1 engines that currently use No.5 bearing rotating air seal, P/No. 4019T60G01. (Applicability)\n\nWhen the actions must be done (compliance timing)\n\n- For CF34-3A1, -3B1 and -3B engines:\n  - Do an initial chip-detector check within 30 flight hours or 3 calendar days from the AD effective date (whichever occurs later). Thereafter, inspect at intervals not to exceed 30 flight hours or 3 calendar days (the AD text uses the phrase \"whichever is the greater\" for recurring intervals). (Compliance 1(a))\n  - Replace the No.5 bearing rotating air seal with P/No.4019T60G03 at the next shop visit when the high-pressure turbine (HPT) is exposed, but no later than 15,000 cycles in service from the AD effective date. (Compliance 2(a))\n\n- For CF34-1A, -3A and -3A2 engines:\n  - Do an initial chip-detector check within 100 flight hours from the AD effective date and thereafter at intervals not to exceed 100 flight hours. (Compliance 1(b))\n\n- Inspection of the magnetic chip detector indicators may be performed by a pilot endorsed on the aircraft type for the CF34-3A1, -3B1 and -3B engines, provided there is a system that (a) tells the pilot when to inspect, (b) records the pilot's signature for that inspection, and (c) notifies maintenance staff to take over if a chip detection is indicated. (Compliance 1(a))\n\nWhy the directive was issued (stated purpose and practical test)\n\n- The stated reason is to correct an unsafe condition connected to the No.5 bearing rotating air seal producing debris that the magnetic chip detector can detect. The AD cross-references FAA AD 2001-12-06.\n- Practical implications: the AD forces operators to increase monitoring of chip detectors until a redesigned air seal is installed, and it mandates replacement of the suspect seal with a specific part number on a defined schedule for some engine models. Those two mechanisms (frequent checks; mandatory part replacement) are the concrete safety controls.\n\nWho pays, who decides, and what changes in behaviour\n\n- Who decides: the Civil Aviation Safety Authority delegate issued the AD; operators are legally required to comply.\n- Who pays: aircraft/engine operators pay for recurring inspections (labour or pilot time and recordkeeping), for maintenance follow-up when debris is found, and for the cost of purchasing and fitting the replacement air seal and any associated shop visit downtime.\n- Behaviour changes: operators must implement a recurring inspection regime for the magnetic chip detector indicators; maintenance organisations must be prepared to remove debris and service the engine when detections occur; affected engines must be fitted with the new air seal by the specified shop visit or cycle limit.\n\nCosts, incentives, trade-offs and implementation risks\n\n- Direct costs: labour for inspections, administrative recordkeeping, parts cost for the P/No.4019T60G03 air seal, and shop visit downtime where HPT exposure is required.\n- Incentives and substitution effects: operators can defer the recurring inspection burden by installing the terminating action part (P/No.4019T60G03), so parts suppliers and maintenance providers gain concentrated business from replacements; operators sensitive to downtime may prioritise replacement at the earliest convenient shop visit.\n- Capture, rent-seeking or concentration risks: the AD specifies a single replacement part number as terminating action; that concentrates demand on the supplier of that part. The AD itself does not specify alternative approved parts or repair schemes.\n- Implementation risks and ambiguities: the compliance text uses slightly different timing phrases for initial vs recurring checks (\"whichever occurs later\" vs \"whichever is the greater\"), which could create uncertainty when applying calendar-day vs flight-hour triggers. Operators must also ensure availability of the replacement seal and schedule HPT exposure shop visits before the 15,000-cycle limit for some models.\n- Compliance burden: more frequent inspections for certain variants (every 30 flight hours or every 3 days for some engines) may be operationally intrusive, especially for short-rotation aircraft.\n\nReference to the official provisions\n\n- The actions and affected part numbers are set out in Requirement 1 and Requirement 2. The specific timing and variant distinctions are in Compliance 1(a)/(b) and Compliance 2(a). The AD notes FAA AD 2001-12-06 as related guidance.\n\nSummary sentence\n\n- In short: the AD mandates frequent chip-detector checks on specified CF34 engines until operators replace a particular No.5 bearing rotating air seal (P/No.4019T60G01) with a new part (P/No.4019T60G03), with variant-specific deadlines and a terminating action that stops the recurring inspections once the new seal is installed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf34-7-no-5-bearing-rotating-air-seal","history":"/api/acts/ad-cf34-7-no-5-bearing-rotating-air-seal/history","analysis":"/api/acts/ad-cf34-7-no-5-bearing-rotating-air-seal/analysis","conflicts":"/api/acts/ad-cf34-7-no-5-bearing-rotating-air-seal/conflicts","importantCases":"/api/acts/ad-cf34-7-no-5-bearing-rotating-air-seal/important-cases","documents":"/api/acts/ad-cf34-7-no-5-bearing-rotating-air-seal/documents"}}