{"id":"F2006B03125","name":"AD/B747/225 - Thrust Reverser Deactivation Pins","slug":"ad-b747-225-thrust-reverser-deactivation-pins","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42497,"registerId":"commonwealth-F2006B03125-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \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/B747/225 Thrust Reverser Deactivation","sectionType":"part","heading":"AD/B747/225 Thrust Reverser Deactivation Pins 6/2000","content":"# AD/B747/225 Thrust Reverser Deactivation Pins 6/2000\n\nApplicability: Model 747-400 series aircraft powered by PW4000 series engines.\n\nRequirement: Replace the deactivation pin, pin bushing in the aft cascade mounting ring, and insert flange on each thrust reverser half with new improved components in accordance with Boeing Alert Service Bulletin 747-78A2165 Revision 1 dated May 13, 1999.\n\nNote: FAA AD 99-26-02 Amdt 39-11462 refers.\n\nCompliance: Unless previously carried out, within 18 months time in service from the effective date of this Airworthiness Directive.\n\nThis Airworthiness Directive becomes effective on 15 June 2000.\n\nBackground: Partial deployment of deactivated thrust reversers has occurred during landing. Actions mandated by this Directive are intended to prevent failure of the thrust reverser deactivation pins, which could result in an in-flight deployment of the thrust reverser. Should this occur controllability of the aircraft will be reduced.\n\n![Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 5 May 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 17 May 2000.","sortOrder":1}],"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":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive targeting a specific mechanical defect in a specific aircraft type. The scope remains tightly focused on the original safety issue — preventing thrust reverser deployment failures — with no expansion beyond the immediate technical fix required."},"complexity_factors":["Single, clearly defined applicability (one aircraft model with specific engines)","One straightforward requirement (replace three named components per Boeing bulletin)","Simple compliance deadline (18 months from effective date)","No defined terms section, no cross-references to other legislation beyond a single FAA reference note","No conditional logic, exceptions, or nested provisions","Short document (under 300 words of substantive text)"],"plain_english_summary":"Australia’s aviation regulator (CASA) issued an Airworthiness Directive requiring operators of Boeing 747-400s with Pratt & Whitney PW4000 engines to replace deactivation pins, pin bushings and insert flanges on each thrust reverser half with improved parts per Boeing instructions.  \n\nThe change prevents dangerous partial or in‑flight deployment of deactivated thrust reversers; compliance was required within 18 months of the directive (from 15 June 2000)."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD stays within the original safety objective described in the Background: preventing failure of thrust-reverser deactivation pins to avoid partial or in-flight deployment. The actions mandated (component replacement per the Boeing service bulletin) are narrowly targeted to that unsafe condition and do not broaden the AD's scope beyond that intent."},"complexity_factors":["Short, single-issue directive (thrust reverser deactivation components)","Single aircraft type scope: Boeing 747-400 series with PW4000 engines (narrow applicability)","One mandatory action: replace three named components on each thrust reverser half","One external technical reference: Boeing Alert Service Bulletin 747-78A2165 Revision 1","One compliance deadline: 18 months from effective date","One cross-reference to FAA AD 99-26-02 (informational note only)","No nested exceptions, conditional paths, or multiple compliance options","Issued under a single regulatory power (subregulation 39.1(1) of CAR 1998)"],"plain_english_summary":"**What this rule does**\n\n- This Airworthiness Directive (AD) requires operators of Boeing 747-400 aircraft with Pratt & Whitney PW4000 engines to replace specific thrust-reverser parts with improved components. (See \"Applicability\" and \"Requirement\".)\n\n- The specific parts to be replaced are: the thrust-reverser deactivation pin, the pin bushing in the aft cascade mounting ring, and the insert flange on each thrust reverser half. The replacement must be done in accordance with Boeing Alert Service Bulletin 747-78A2165 Revision 1 (13 May 1999). (See \"Requirement\".)\n\n- The work must be completed within 18 months in service from the AD's effective date, unless already done. The AD became effective on 15 June 2000. (See \"Compliance\" and effective date.)\n\n**Who this affects**\n\n- Operators/owners of Boeing 747-400 series aircraft equipped with PW4000 engines. Maintenance organisations that service those aircraft will carry out the work. The Civil Aviation Safety Authority (CASA) delegate issued the AD under powers in the Civil Aviation Regulations. (See heading and issuance.)\n\n**Why it matters (mechanically)**\n\n- The AD responds to incidents of partial deployment of thrust reversers during landing. It aims to prevent failure of the deactivation pins that could allow an in-flight deployment of a thrust reverser, a condition that would reduce the aircraft's controllability. (See \"Background\".)\n\n**How it works in practice**\n\n- The operator arranges for the specified parts to be replaced on each thrust reverser half, following the detailed procedures in the Boeing Alert Service Bulletin referenced in the AD. A properly certificated maintenance organisation will install the new components and record the compliance action in the aircraft maintenance records. (See \"Requirement\" and the Boeing Service Bulletin reference.)\n\n**Who pays and who decides**\n\n- Operators pay for parts, labour and any associated downtime. CASA (via its delegate) issues the mandatory direction; the technical steps are governed by the Boeing Alert Service Bulletin. The AD also notes a corresponding FAA AD (99-26-02) as a related regulatory reference. (See the Note.)\n\n**Costs, incentives, trade-offs and implementation risks**\n\n- Costs: concentrated on affected operators — parts, certified maintenance labour, and aircraft out-of-service time. The AD does not provide funding or exemptions.\n\n- Incentives: Operators are required to comply within the stated timeframe; failing to comply would make an aircraft non-compliant with its airworthiness directives and could lead to regulatory enforcement or grounding.\n\n- Trade-offs: The AD trades short-term costs (parts, maintenance time) for reduced risk of an in-flight thrust-reverser deployment. The trade-off is explicit and narrow: safety mitigation vs. operator expense and scheduling.\n\n- Implementation risks: availability of the improved parts, maintenance capacity and scheduling pressure for operators with small fleets could cause practical difficulties in meeting the 18-month window. The AD relies on the Boeing Service Bulletin for technical detail; any ambiguity or supply constraint in that bulletin could delay compliance.\n\n**Operational effect on markets and competition**\n\n- The AD imposes an operational cost on all affected operators equally by aircraft type. It does not change operating rules, ownership, or market entry conditions beyond the cost and downtime of compliance. Smaller operators may face relatively higher per-aircraft disruption if they have fewer aircraft to stand down for maintenance.\n\n**Legal basis and cross-reference**\n\n- The AD is issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 (the delegate's issuing power). It explicitly references Boeing Alert Service Bulletin 747-78A2165 Revision 1 and notes FAA AD 99-26-02. (See heading, Requirement, and Note.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-225-thrust-reverser-deactivation-pins","history":"/api/acts/ad-b747-225-thrust-reverser-deactivation-pins/history","analysis":"/api/acts/ad-b747-225-thrust-reverser-deactivation-pins/analysis","conflicts":"/api/acts/ad-b747-225-thrust-reverser-deactivation-pins/conflicts","importantCases":"/api/acts/ad-b747-225-thrust-reverser-deactivation-pins/important-cases","documents":"/api/acts/ad-b747-225-thrust-reverser-deactivation-pins/documents"}}