{"id":"F2006B01913","name":"AD/A320/22 - Thrust Reverser/ECU Electrical Harness Assemblies","slug":"ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41135,"registerId":"commonwealth-F2006B01913-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A320/22 - Thrust Reverser/ECU Electrical Harness Assemblies","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)  \nAirbus Industrie A319, A320 and A321 Series Aeroplanes\n\nAD/A320/22 Thrust Reverser/ECU Electrical Harness Assemblies 12/91\n\nDM\n\nApplicability: 1. All A320 aircraft fitted with CFM56-5A engines and Electrical Harness Assemblies P/No 238W0908-511, 238W0904-509 and 238W0904-511.\n\n2. All Electrical Harness Assemblies P/No 238W0908-511, 238W0904-509 and 238W0904-511 held as spares.\n\nRequirement: 1. Action in accordance with Phase 1 of Airbus Industries All Operator Telex (AOT) 71-01.\n\n2. Action in accordance with Phase 2 of Airbus Industries All Operator Telex (AOT) 71-01.\n\nNote: Rohr Industries Service Bulletin RA32071-63 also refers.\n\nCompliance: 1. For installed harnesses \\- prior to 100 hours’ Time in Service after 23 October 1991.\n\nFor harnesses held as spares \\- prior to installation on an aircraft.\n\n2. For harness assemblies found during phase 1 to have moisture or corrosion present\n\n\\- prior to exceeding 600 hours’ time in service after 23 October 1991.\n\nFor harness assemblies found during phase 1 to have no moisture or corrosion present - within 3000 hours’ time in service after 23 October 1991.\n\nBackground: One operator of A320 aircraft equipped with CFM56-5A powerplants has reported an uncommanded engine power reduction to idle in flight which has been partly attributed to corrosion in the ECU electrical harness. Compliance with this AD requires an inspection of the thrust reverser and ECU harness assemblies, for corrosion and moisture ingress, and the installation of draining provisions in the harness chafe guards.","sortOrder":0}],"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD remains narrowly focused on a specific safety problem: moisture/corrosion in defined thrust reverser/ECU harness assemblies on A320-family aeroplanes with CFM56-5A engines. It targets both installed harnesses and spares and prescribes inspection and a specific modification (draining provisions). There is no substantive expansion beyond that original safety objective — the measure does not add unrelated obligations, broaden to other aircraft types or parts, or create ongoing regulatory programmes beyond the inspection/modification and follow-up windows set out in the AD."},"complexity_factors":["Short, single-issue AD (limited scope and length)","3 specific harness part numbers listed in the applicability","2 applicability categories (installed on aircraft; held as spares)","Two-phase compliance structure (Phase 1 and Phase 2) dependent on Airbus AOT 71-01","Conditional follow-up compliance windows (100 hours initial window; then 600 hours if moisture/corrosion found, 3000 hours if not)","Cross-reference to Airbus AOT 71-01 and Rohr Industries Service Bulletin RA32071-63 (external documents required to execute work)","Fixed reference date (23 October 1991) creating historical compliance deadlines","Operational requirements (tracking TIS — time in service — on affected harnesses)"],"plain_english_summary":"**What this directive does (mechanics first)**\n\n- This Airworthiness Directive (AD) requires operators of certain Airbus A320-family aeroplanes to inspect specific electrical harness assemblies that connect the thrust reverser and the Electronic Control Unit (ECU) for signs of moisture and corrosion, and to install ‘‘draining provisions’’ (modifications to the harness chafe guards that let water drain away). (Applicability; Requirement)\n\n- The AD applies to: all A319/A320/A321 aeroplanes fitted with CFM56-5A engines that have harness part numbers 238W0908-511, 238W0904-509 or 238W0904-511 installed, and to those same harness assemblies when they are held as spares. (Applicability)\n\n- The required actions are set out in two phases specified by Airbus All Operator Telex (AOT) 71-01. The AD also references Rohr Industries Service Bulletin RA32071-63 as related information. (Requirement; Note)\n\n- Timing rules: for harnesses already installed, the initial inspection must be done before the harness accumulates 100 hours of flight time after 23 October 1991; for spares the inspection is required before they are installed. If the Phase 1 inspection finds moisture or corrosion, a follow-up action must be completed before the harness reaches 600 hours’ time-in-service after 23 October 1991. If no moisture or corrosion is found at Phase 1, the follow-up must be done within 3000 hours’ time-in-service after 23 October 1991. (Compliance)\n\n**Who this affects and who pays**\n\n- Aircraft operators that fly A319/A320/A321 aircraft with CFM56-5A engines and the specified harness part numbers are the primary parties affected. They must schedule inspections and modifications and pay for labour, possible replacement of corroded harnesses, and any aircraft downtime. (Applicability; Compliance)\n\n- Operators who hold the listed harness assemblies as spares must inspect them before using them; spare suppliers or maintainers will therefore need to ensure those spares comply before sale or installation. (Applicability; Compliance)\n\n- Maintenance organisations (OEM dealers, airline in-house maintenance, or independent MROs) will perform the inspections and installation work; they earn revenue from the work but must have the capability and parts to comply. (Requirement)\n\n**Why the regulator says this matters (the stated safety reason)**\n\n- The AD cites a reported in-flight uncommanded engine power reduction to idle that was partly attributed to corrosion in the ECU electrical harness. The inspection and draining modification are required to detect and mitigate moisture and corrosion that could disrupt ECU wiring and engine control. (Background)\n\n**Practical effects, incentives and trade-offs**\n\n- Behavioural change required: operators must track affected harnesses, carry out a Phase 1 inspection quickly (within 100 hours TIS if installed), follow Airbus AOT instructions for Phase 2 work, and replace or repair any harnesses where moisture/corrosion is found. (Requirement; Compliance)\n\n- Costs and burdens: direct costs are inspection labour, possible replacement parts, and aircraft downtime while the work is done. These costs are concentrated on operators of the affected fleet and on spare-harness suppliers. The modifying work may be performed by third‑party MROs if they have relevant approvals. (Applicability; Requirement)\n\n- Implementation risk: correct execution depends on access to the harness routing, availability of the recommended parts and tooling, and faithful compliance with Airbus AOT procedures. If the draining modification or inspection is poorly done, residual risk remains. (Requirement; Note)\n\n- Market effects: the directive does not alter competition or ownership rights directly. It imposes a compliance cost on operators that could slightly increase operating costs for affected aircraft types. Independent maintenance providers can perform the required work if authorised, so the AD does not restrict who may carry it out provided they meet applicable standards. (Applicability; Requirement)\n\n**Concrete mechanics to comply**\n\n- Follow Phase 1 of Airbus AOT 71-01 to inspect the thrust reverser/ECU harness assemblies for moisture/corrosion. (Requirement)\n- Based on Phase 1 findings, follow Phase 2 of Airbus AOT 71-01 which includes installing draining provisions in the harness chafe guards and any corrective action required by the AOT. (Requirement)\n- Meet the specified compliance windows tied to hours-in-service or prior to installation (see Compliance). (Compliance)\n\n**Source claims vs practical costs and trade-offs**\n\n- The AD’s stated purpose (preventing unseen corrosion that could cause engine control problems) is concrete and testable: inspections and drainage reduce moisture ingress and allow removal or repair of corroded wiring. (Background)\n\n- The cost of that safety mitigant is immediate and concentrated on operators and spare-part holders in the short term (inspection and modification costs, parts and downtime). The benefit is a reduced probability of ECU wiring faults related to moisture/corrosion. Whether the benefit justifies the cost is an operator-level commercial decision influenced by the frequency of the fault and the cost of uncommanded power reduction events; the AD chooses precaution by mandating the work. (Applicability; Requirement; Background)\n\n**Where to look in the AD**\n\n- Applicability: which aeroplanes and part numbers are covered.\n- Requirement: follow Phase 1 and Phase 2 of Airbus AOT 71-01; install draining provisions.\n- Compliance: exact time windows (100 hours; 600 hours if corrosion found; 3000 hours if not) and spares rule (inspect before installation).\n- Background: incident prompting the AD (reported in-flight uncommanded power reduction)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific technical defect in specific aircraft configurations. It has not expanded beyond its original purpose of addressing the corrosion/moisture ingress issue in the specified harness assemblies."},"complexity_factors":["Short, single-purpose directive with clear applicability criteria","Only 3 specific part numbers to identify","Two-phase compliance structure with conditional deadlines based on inspection findings","Minimal cross-referencing (only references Airbus AOT 71-01 and Rohr Industries Service Bulletin)","No defined terms section or extensive interpretation provisions","Straightforward temporal compliance framework (flight hours after fixed date)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires specific inspections and modifications to certain Airbus A320 aircraft.\n\n**What it does:**\n- **Targets:** Airbus A319, A320, and A321 planes fitted with specific CFM56-5A engines and particular electrical harness part numbers (238W0908-511, 238W0904-509, and 238W0904-511).\n- **The problem:** An airline reported an engine unexpectedly dropping to idle power mid-flight. Investigators traced this to **corrosion and moisture** getting into the electrical harness that connects to the Engine Control Unit (ECU) — basically the computer that manages the engine.\n- **What must happen:**\n  - **Phase 1:** Inspect the thrust reverser and ECU electrical harnesses for moisture and corrosion.\n  - **Phase 2:** Install drainage provisions (holes or channels to let water escape) in the harness protective covers (called \"chafe guards\").\n\n**Who it affects:**\n- Airlines operating the specified Airbus models with those engine and harness combinations.\n- Anyone holding those specific harness part numbers as spare parts.\n\n**Deadlines:**\n- **Installed harnesses:** Must complete Phase 1 within 100 flight hours after 23 October 1991.\n- **Spare harnesses:** Must be inspected before being installed on any aircraft.\n- **Phase 2 timing depends on Phase 1 findings:**\n  - If moisture or corrosion found: fix within 600 flight hours after 23 October 1991.\n  - If clean: fix within 3,000 flight hours after 23 October 1991.\n\n**Why it matters:** Uncommanded engine power reductions are extremely dangerous. This directive prevents potential engine failures or loss of thrust during critical phases of flight like takeoff or landing."}},"importantCases":[],"_links":{"self":"/api/acts/ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies","history":"/api/acts/ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies/history","analysis":"/api/acts/ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies/analysis","conflicts":"/api/acts/ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies/conflicts","importantCases":"/api/acts/ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies/important-cases","documents":"/api/acts/ad-a320-22-thrust-reverser-ecu-electrical-harness-assemblies/documents"}}