{"id":"F2006L03418","name":"AD/TAY/16 - Engine Electronic Controller - Inspection/Replacement","slug":"ad-tay-16-engine-electronic-controller-inspection-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":60876,"registerId":"commonwealth-F2006L03418-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Rolls Royce Turbine Engines - Tay Series","sectionType":"division","heading":"Rolls Royce Turbine Engines - Tay Series","content":"### Rolls Royce Turbine Engines - Tay Series\n\n| AD/TAY/16 | Engine ElectronicController - Inspection/Replacement | 11/2006 |\n| --------- | ---------------------------------------------------- | ------- |\n\n| Applicability: | All TAY611-8C engines, all serial numbers, if equipped with Engine Electronic Controller (EEC), part number (P/N) TEEC200004AE.                                                                                                                                                                  |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n|                | Note 1: These engines are known to be installed on Gulfstream GIV-X aircraft.                                                                                                                                                                                                                    |\n| Requirement:   | 1. Electrically check the two transorbs of the EEC on at least one engine of the aircraft in accordance with the instructions of Rolls-Royce Deutschland Alert Service Bulletin (ASB) TAY-73-A1703 dated 11 August 2006 or later EASA approved revision.                                         |\n|                | 2. If, as a result of the Requirement 1 check, an EEC is found to be damaged, replace the EEC with an undamaged unit in accordance with the instructions of ASB TAY-73-A1703 or later EASA approved revision taking into account the following conditions:                                       |\n|                | a. If no replacement EEC is available, electrically check the two transorbs of the EEC installed on the other engine of the aircraft in accordance with the instructions of ASB TAY-73-A1703 or later EASA approved revision.                                                                    |\n|                | b. If this EEC is also found to be damaged, at least one damaged EEC must be replaced in accordance with the instructions of ASB TAY-73-A1703 or later EASA approved revision.                                                                                                                   |\n|                | 3. Repeat the Requirement 2 inspection in accordance with the instructions of ASB TAY-73-A1703 or later EASA approved revision.                                                                                                                                                                  |\n|                | Note 2: When the aircraft has been modified in accordance with Gulfstream Aircraft Service Change 036, only one single (repeat) inspection is required to establish that at least one EEC is undamaged. If so, the periodic inspections are not required, or may be discontinued, as applicable. |\n|                | Note 3: EASA AD 2006-0268-E refers.                                                                                                                                                                                                                                                              |\n| Compliance:    | For Requirement 1 - Within 300 flight hours time in service (TIS) after the effective date of this Directive.                                                                                                                                                                                    |\n|                | For Requirement 2 - Before next flight after the Requirement 1 check.                                                                                                                                                                                                                            |\n\n|             | For Requirement 3 - At intervals not to exceed 500 hours TIS.                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Airworthiness Directive becomes effective on 26 October 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background: | Some EECs, returned from in-service to the manufacturer, had damaged transorbs. A transorb is a diode type device in the EEC connect module that protects the EEC from the effects of lightning strikes by conducting the current to the ground. A damaged transorb may compromise the EECs ability to protect circuits from damage during a lightning strike event. Investigation has shown that the transorbs could be damaged due to an inadequate bonding between the aircraft and the engine. |\n|             | As the EEC aircraft power supply 0 Volt return line is clamped to the engine through a transorb while it is bonded to the aircraft, a difference in potential between the engine and the aircraft could result in a transorb damage. To prevent this, an additional bonding lead must be installed between the aircraft and the engine. In addition, all EEC units need to be electrically checked to find out if any transorb is damaged.                                                         |\n|             | The purpose of this Directive is to establish that at least one engine installed on an aircraft has an EEC installed with undamaged transorbs. Rolls-Royce Deutschland Alert Service Bulletin TAY-73-A1703 describes the electrical check of two transorbs of the EEC on one engine of the aircraft.                                                                                                                                                                                               |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n15 September 2006","sortOrder":0},{"sectionNumber":"AD/TAY/16","sectionType":"part","heading":"AD/TAY/16","content":"## AD/TAY/16","sortOrder":1},{"sectionNumber":"Engine ElectronicController - Inspection","sectionType":"part","heading":"Engine ElectronicController - Inspection/Replacement","content":"## Engine Electronic  \nController - Inspection/Replacement","sortOrder":2},{"sectionNumber":"11/2006","sectionType":"part","heading":"11/2006","content":"## 11/2006","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains a narrow, focused scope on the specific safety issue of transorb damage in Tay 611-8C engine controllers. The requirements remain tightly coupled to the original safety purpose: ensuring lightning strike protection through inspection and replacement protocols. The inclusion of the Gulfstream service change exemption (Note 2) and the alternative procedure when spare parts are unavailable are natural operational accommodations rather than scope creep."},"complexity_factors":["Single specific technical subject matter (transorb inspection in EEC units)","Clear sequential requirements (1, 2, 3) with logical dependencies","Limited cross-referencing — only references one external technical document (Rolls-Royce ASB TAY-73-A1703) and one EASA AD","Straightforward applicability criteria (specific engine model + specific part number)","Simple conditional logic (if damaged → replace; if no spare → check other engine)","No nested definitions or interpretation sections","Clear compliance timeframes (300 hours, before next flight, 500 hour intervals)","Document is approximately 1 page in length with minimal structural complexity"],"plain_english_summary":"This AD requires inspection—and replacement if necessary—of Engine Electronic Controllers (EECs) on Rolls‑Royce Tay 611‑8C engines (commonly on Gulfstream GIV‑X jets) after reports of damaged transorbs that can fail to protect against lightning due to inadequate electrical bonding. \n\nIt affects operators of those engines in Australia: controllers must be tested and faulty units replaced (with recurring checks until a bonding modification is done) to prevent lightning‑induced engine computer failures and maintain safe flight."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive stays within the original technical purpose described in its background: identify damaged transorbs in specified EECs and ensure at least one installed EEC per aircraft has undamaged transorbs, and to address bonding issues between engine and airframe. It does not expand beyond that focus — it prescribes inspections, conditional replacements and references the manufacturer’s ASB for corrective steps (including bonding lead installation in the background). The Gulfstream Service Change 036 exception narrows recurring inspections for already‑modified aircraft rather than expanding scope."},"complexity_factors":["Single engine type but limited to EEC with a specific part number (TEEC200004AE) — applicability narrow but requires serial/part tracking","Three linked Requirements with conditional branching (initial check → possibly replace → fallback check on other engine if no replacement available → mandatory replacement before next flight if damaged)","Recurring inspection interval (500 flight hours) with an explicit exception for aircraft modified per Gulfstream Service Change 036","Delegation of procedural detail to an external document (Rolls‑Royce ASB TAY‑73‑A1703 or later EASA‑approved revision), increasing cross‑document dependency","Cross‑reference to an EASA AD (2006‑0268‑E) and to manufacturer service/change documents, creating layered compliance obligations","Time‑sensitive compliance deadlines (within 300 flight hours; replacement before next flight) that create operational and supply chain pressure","Ambiguity in the AD text about whether installation of the bonding lead is mandated by the AD itself or specified via the ASB (practical compliance depends on the ASB content)"],"plain_english_summary":"**What this airworthiness directive does (mechanics)**\n\n- **Applies to:** All Rolls‑Royce TAY611‑8C engines of any serial number that are fitted with an Engine Electronic Controller (EEC) with part number TEEC200004AE. The note states these engines are known to be fitted to Gulfstream GIV‑X aircraft.\n\n- **Required actions:**\n  - 1) Within 300 flight hours, electrically check the two \"transorbs\" (surge‑protection diodes) in the EEC on at least one engine, using the procedure in Rolls‑Royce Deutschland Alert Service Bulletin (ASB) TAY‑73‑A1703 (or a later EASA‑approved revision). \n  - 2) If that check shows the EEC is damaged, replace it with an undamaged unit following the ASB instructions. If no replacement unit is available, you must check the other engine's EEC; if that one is also damaged, at least one damaged EEC must be replaced before the next flight. \n  - 3) Repeat the inspection in Requirement 2 at intervals not exceeding 500 flight hours, following the ASB (or later EASA‑approved revision).\n\n- **Exception / modification:** If the aircraft has been modified per Gulfstream Aircraft Service Change 036, only a single repeat inspection is needed to demonstrate at least one EEC has undamaged transorbs; if that single inspection shows an undamaged EEC, the periodic 500‑hour inspections are not required or may be discontinued, as applicable.\n\n- **How compliance is enforced in practice:** The AD mandates following the Rolls‑Royce ASB (or any later EASA‑approved revision). The AD gives specific time limits for the initial check (300 flight hours) and for replacement (before next flight if damage is found), and sets a recurring inspection interval (500 flight hours) unless the Gulfstream modification exemption applies.\n\n**Why the rule exists (stated purpose) and how that maps to costs and incentives**\n\n- The directive states the reason: transorbs protect the EEC from lightning by shunting current to ground; some transorbs were returned damaged, apparently due to inadequate electrical bonding between the engine and aircraft. A damaged transorb could reduce EEC protection during a lightning event. The stated purpose is to ensure at least one installed EEC per aircraft has undamaged transorbs.\n\n- Mechanically, the AD forces operators to inspect and, if necessary, replace EECs and to follow the manufacturer ASB for corrective measures (which can include installing an additional bonding lead to reduce the chance of damage, per the background). The AD therefore shifts inspection, replacement and modification costs and operational choices to the aircraft operator (owner/operator of the affected Gulfstream/TAY‑equipped aircraft).\n\n**Practical effects, trade‑offs and implementation points to watch**\n\n- Who pays: operators pay for inspections, potential replacements, parts and labor, and any downtime. If replacements are required \"before next flight,\" that can create immediate operational disruption and potential temporary grounding.\n\n- Supply and timing risk: the AD permits checking the other engine only if no replacement EEC is available; this creates a dependence on spare EEC inventory. Limited spare availability could increase aircraft downtime or force multiple checks.\n\n- Reliance on external documents: the AD delegates technical detail to Rolls‑Royce ASB TAY‑73‑A1703 (or later EASA‑approved revisions). That centralises procedural discretion with the manufacturer and with EASA approvals; operators must follow the ASB text, not just the AD's high‑level requirements.\n\n- Compliance burden: an initial mandatory check within 300 flight hours and recurring 500‑hour checks (unless Gulfstream Service Change 036 applies) impose periodic maintenance work. The operator must track serial numbers and P/N to determine applicability.\n\n- Behavioural effect on private actors: operators will likely increase inspection frequency, maintain or obtain spare EECs, and may choose to install the bonding lead modification (per the ASB or service change) to avoid repeated inspections. That shifts some discretionary maintenance choices toward preventive modification.\n\n- Concentrated vs diffuse effects: the costs are concentrated on operators of the specific aircraft/engine/EEC combination; safety benefits (if realised) are diffuse — they accrue to aircraft occupants and third parties. The AD’s reliance on an ASB for corrective steps gives the manufacturer a central role in specifying remedies.\n\n**References within the directive:**\n- Requirement numbering: Requirement 1 (initial check), Requirement 2 (replacement rules), Requirement 3 (repeat inspections). \n- Notes: Note 1 (installation on Gulfstream GIV‑X), Note 2 (Gulfstream Service Change 036 modification effect), Note 3 (EASA AD 2006‑0268‑E referred).\n\n**Bottom line:** The AD requires inspection of the EEC transorbs on TAY611‑8C engines with EEC P/N TEEC200004AE, replacement of damaged EECs before further flight, and recurring inspections every 500 flight hours unless a specific Gulfstream modification has been done. Operators bear the cost and operational impact, and must follow the Rolls‑Royce ASB procedures (or later EASA‑approved revisions) to comply."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-tay-16-engine-electronic-controller-inspection-replacement","history":"/api/acts/ad-tay-16-engine-electronic-controller-inspection-replacement/history","analysis":"/api/acts/ad-tay-16-engine-electronic-controller-inspection-replacement/analysis","conflicts":"/api/acts/ad-tay-16-engine-electronic-controller-inspection-replacement/conflicts","importantCases":"/api/acts/ad-tay-16-engine-electronic-controller-inspection-replacement/important-cases","documents":"/api/acts/ad-tay-16-engine-electronic-controller-inspection-replacement/documents"}}