{"id":"F2006B09634","name":"AD/F100/32 - Thrust Reverser Electrical Control Modification","slug":"ad-f100-32-thrust-reverser-electrical-control-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":54432,"registerId":"commonwealth-F2006B09634-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/F100/32 - Thrust Reverser Electrical Control Modification","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)  \nFokker F100 (F28 Mk 100) Series Aeroplanes\n\nAD/F100/32 Thrust Reverser Electrical Control Modification 5/99\n\nApplicability: All F.28 Mk.0070 and Mk.0100 aeroplanes.\n\nRequirement: 1\\. Modify the Flight Warning Computer (FWC) and the Thrust Reverser Stow Limit relay wiring in accordance with Fokker Service Bulletin (SB) F100-78-012 dated 22 November 1996.\n\n    2. Perform operational checks of each Thrust Reverser Secondary Lock Actuator and Primary Lock Switch, and perform an operational check of the Thrust Reverser Indicating and Alerting System, including feedback cable mechanism, in accordance with Fokker SB F100-78-013 dated 22 November 1996.\n\n    3. For aircraft that are post SB F100-78-004, at the effective date of this directive, perform a functional check for internal leakage of the Thrust Reverser Selector Valve in accordance with Maintenance Review Board (MRB) task 783200-00-02.\n\n    4. Flight Manual Changes\n\nRevise the Abnormal Procedures Section of the Aircraft Flight Manual (AFM) to include the Flight Manual information specified in RLD AD BLA nr: 1996- 140/2.\n\nThis task may be accomplished by inserting a copy of RLD AD BLA nr: 1996- 140/2, Appendix 1 into the Abnormal Procedures Section of the AFM.\"\n\n    5. Modify the wiring of the Thrust Reverser Electrical Control System and Indication and Warning System in accordance with Fokker SB F100-78-014 dated 15 August 1998.\n\n    6. Modify all Aft Engine Cowling part number 1159P41440, in accordance with Fokker Component SB P41440-78-05 dated 15 August 1998.\n\n    7. Install a Voltage Spike Protection Diode over the coil of the Thrust Reverser Secondary Lock Solenoid on all Aft Engine Cowling part number 1159P41440, in accordance with Fokker Component SB P41440-78-05 dated 15 August 1998.\n\nNote: Netherlands AD 1996-140/2 refers.\n\nCompliance: 1. Prior to 22 June 1999.\n\n    2. Within 500 flight cycles after the accomplishment of Requirement 1 and thereafter at intervals not to exceed 500 flight cycles.\n\n    3. Either:\n\n    within 12 000 hours time in service (TIS) after modification in accordance with Fokker SB F100-78-004, or\n\n    b. within 6000 hours TIS after Fokker SB F100-78-012 has been accomplished.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\nWhichever is the later, and thereafter at intervals not to exceed 12 000 hours TIS.\n\n    4. Prior to 22 July 1999.\n\n    5. Before fitting to an aircraft or prior to 22 September 2000.\n\n    6. Before fitting to an aircraft or prior to 22 September 2000.\n\n    7. Before fitting to an aircraft or prior to 22 September 2000. This Airworthiness Directive becomes effective on 20 May 1999.\n\nBackground: To prevent the possibility of the accidental deployment of the Thrust Reverser during take-off Fokker have issued operational measures and modifications to the FWC wiring.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The directive remains focused on the original safety objective: preventing accidental deployment of thrust reversers during take-off. The measures consolidate wiring changes, hardware retrofits, AFM updates and recurring functional checks that all address that single hazard. While the AD adds multiple discrete technical tasks and recurring inspections, these are direct implementations of the stated safety purpose rather than a substantive expansion into unrelated regulatory areas."},"complexity_factors":["Seven discrete mandatory actions (Requirements 1–7) with different technical scopes (wiring, functional checks, fluid leakage check, AFM update, cowling modification, diode installation).","Multiple external documents required: Fokker SB F100-78-012, F100-78-013, F100-78-014, Component SB P41440-78-05, and MRB task 783200-00-02.","Varied compliance timing rules: fixed calendar deadlines (e.g. prior to 22 June 1999), intervals measured in flight cycles (500 cycles), and intervals measured in hours TIS (6,000/12,000 hours), with \"whichever is later\" logic for Requirement 3.","Recurring inspection obligation (every 500 flight cycles) adds administrative and operational complexity.","Part-number-specific hardware mandate (Aft Engine Cowling p/n 1159P41440) plus installation of a specific diode — creates supply-chain and installation constraints.","Cross-reference to another authority’s AD (Netherlands AD 1996-140/2) for AFM text, adding dependence on non‑domestic material.","Conditional applicability: Requirement 3 applies only to aircraft that are post SB F100-78-004 at the AD effective date, creating a population split.","Different deadlines for initial compliance vs. \"before fitting\" clauses for later installations (Requirements 5–7) increase scheduling complexity."],"plain_english_summary":"**What this directive does**\n\n- **Applies to:** All Fokker F100 series aeroplanes listed as F.28 Mk.0070 and Mk.0100.\n\n- **Primary effect:** Requires operators to change electrical wiring, retrofit hardware, update manuals and perform recurring checks to reduce the risk that a thrust reverser could accidentally deploy during take-off.\n\n**Mechanical requirements (what must be done and when)**\n\n- Modify the Flight Warning Computer (FWC) and the Thrust Reverser Stow Limit relay wiring to the configuration in Fokker Service Bulletin (SB) F100-78-012 (Requirement 1). Compliance deadline: prior to 22 June 1999.\n\n- Carry out operational checks of each Thrust Reverser Secondary Lock Actuator and Primary Lock Switch, and check the Thrust Reverser Indicating and Alerting System (including feedback cable mechanism), to the procedure in Fokker SB F100-78-013 (Requirement 2). These functional checks must be done within 500 flight cycles after Requirement 1 is completed and then repeated at intervals not exceeding 500 flight cycles.\n\n- For aeroplanes that previously had SB F100-78-004 done, perform a functional check for internal leakage of the Thrust Reverser Selector Valve per MRB task 783200-00-02 (Requirement 3). Timing: either within 12,000 hours time in service (TIS) after the SB F100-78-004 modification, or within 6,000 hours TIS after SB F100-78-012 was done — whichever is later — and repeat every 12,000 hours TIS thereafter.\n\n- Update the Aircraft Flight Manual (AFM) Abnormal Procedures section by inserting the Flight Manual text from RLD AD BLA nr: 1996-140/2, Appendix 1 (Requirement 4). Compliance deadline: prior to 22 July 1999.\n\n- Further modify the wiring of the Thrust Reverser Electrical Control System and Indication and Warning System per Fokker SB F100-78-014 (Requirement 5). This must be done before fitting to an aircraft or prior to 22 September 2000.\n\n- Modify all Aft Engine Cowling part number 1159P41440 as specified in Fokker Component SB P41440-78-05 (Requirement 6). Do this before fitting to an aircraft or prior to 22 September 2000.\n\n- Install a voltage-spike protection diode over the coil of the Thrust Reverser Secondary Lock Solenoid on every Aft Engine Cowling part number 1159P41440 per Fokker Component SB P41440-78-05 (Requirement 7). Do this before fitting to an aircraft or prior to 22 September 2000.\n\n**Stated rationale**\n\n- The directive’s stated purpose is to prevent the possibility of accidental thrust reverser deployment during take-off; it does this by mandating wiring and hardware changes, functional checks, and flight manual updates (Background and Requirements 1–7).\n\n**Who pays and who decides**\n\n- Aircraft owners/operators pay for parts, labour and downtime required by the modifications and checks (requirements 1–7).\n\n- Maintenance organisations/approved engineers perform the mandated modifications and recurring checks, following the specified Fokker service and component bulletins and MRB task (Requirements 1–7).\n\n- The Civil Aviation Safety Authority enforces the directive by setting compliance deadlines and intervals.\n\n**Behavioural and operational effects**\n\n- Operators must schedule and budget for the modification work, AFM changes and recurring inspections; aircraft may be grounded or out of service while work is done (Requirements 1–7).\n\n- Operators will need to track compliance dates, TIS and flight-cycle counters for the recurring tasks (Requirements 2 and 3).\n\n- Maintenance providers must follow multiple external technical documents (Fokker SBs and MRB task) and install specific part-number changes (e.g. Aft Engine Cowling p/n 1159P41440) and components (protection diodes) where required (Requirements 5–7).\n\n**Costs, trade-offs and implementation risks**\n\n- Direct costs: purchase of parts (cowling, diodes), labour to rewire/modify systems, time to perform and document operational checks, and potential ferry or downtime costs while aircraft are unavailable (Requirements 1, 5–7).\n\n- Ongoing costs: recurring functional checks at 500 flight-cycle intervals and selector-valve leakage checks at up to 12,000-hour intervals create sustained maintenance burden (Requirements 2 and 3).\n\n- Implementation risk: the work depends on following several different Fokker service bulletins and an MRB task precisely; incorrect wiring or improper installation could create new faults. The AD requires installation of specific hardware and AFM text, so quality control and correct documentation are essential (Requirements 1–7).\n\n- Supply/operational risk: parts with a particular part number are mandated (cowling p/n 1159P41440), which could create lead-time or compatibility issues if spares are scarce (Requirements 6–7).\n\n- Incentives and allocation of costs: operators bear the costs of compliance. If some modifications are done only when a cowling is \"fitted to an aircraft\" (pre‑fitting clauses in Requirements 5–7), owners scheduling heavy maintenance or part replacements may reduce incremental cost, but the AD still sets absolute deadlines if the part is already fitted.\n\n**Cross-references and dependencies**\n\n- The AD requires actions that are described in multiple external documents (Fokker SBs F100-78-012, -013, -014; Component SB P41440-78-05; MRB task 783200-00-02) and inserts AFM material from RLD AD BLA nr: 1996-140/2. Compliance therefore depends on access to those documents and their instructions (Requirements 1–7).\n\n**Net effect**\n\n- Mechanically, the AD forces electrical and hardware changes, updates the AFM, and establishes recurring inspection intervals to mitigate the single identified hazard (unintended thrust reverser deployment). The operator pays and the maintenance provider does the work, under oversight by the regulator. The main trade-offs are one-off retrofit costs and ongoing inspection burden in exchange for the risk reduction these measures are designed to provide."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope: mandating specific safety modifications to thrust reverser systems on Fokker F100 aircraft. The seven requirements all relate to the single safety issue of preventing accidental thrust reverser deployment. There is no evidence of scope creep beyond this original technical safety purpose."},"complexity_factors":["Multiple numbered requirements (7 distinct tasks) with different compliance deadlines","Cross-references to external technical documents: 4 different Fokker Service Bulletins, 1 Component Service Bulletin, 1 Maintenance Review Board task, and 1 Netherlands Airworthiness Directive","Conditional compliance logic in Requirement 3 ('whichever is the later')","Technical aviation terminology throughout (e.g., 'Thrust Reverser Stow Limit relay', 'Voltage Spike Protection Diode', 'Secondary Lock Actuator')","Nested timing requirements (e.g., 'within 500 flight cycles after the accomplishment of Requirement 1')","Applicability condition for Requirement 3 limited to 'aircraft that are post SB F100-78-004'"],"plain_english_summary":"The Civil Aviation Safety Authority (CASA) requires all Fokker F100 (F28 Mk 100) operators in Australia to carry out mechanical and electrical modifications to thrust reverser systems and update procedures to prevent accidental reverser deployment during take‑off.  \n\nCompliance involves wiring and hardware changes, checks and flight‑manual updates, with specific tasks due by set dates or within defined flight hours/cycles."},"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-f100-32-thrust-reverser-electrical-control-modification","history":"/api/acts/ad-f100-32-thrust-reverser-electrical-control-modification/history","analysis":"/api/acts/ad-f100-32-thrust-reverser-electrical-control-modification/analysis","conflicts":"/api/acts/ad-f100-32-thrust-reverser-electrical-control-modification/conflicts","importantCases":"/api/acts/ad-f100-32-thrust-reverser-electrical-control-modification/important-cases","documents":"/api/acts/ad-f100-32-thrust-reverser-electrical-control-modification/documents"}}