{"id":"F2007L03975","name":"AD/ERJ-170/12 - Inertial Reference Unit Improvement","slug":"ad-erj-170-12-inertial-reference-unit-improvement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":70697,"registerId":"commonwealth-F2007L03975-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Embraer ERJ-170 Series Aeroplanes","sectionType":"division","heading":"Embraer ERJ-170 Series Aeroplanes","content":"### Embraer ERJ-170 Series Aeroplanes\n\n| AD/ERJ-170/12 | Inertial Reference Unit Improvement | 11/2007 |\n| ------------- | ----------------------------------- | ------- |\n\n| Applicability: | All ERJ-170( ) aircraft models.                                                                                                                                                                                                                                                                                                                              |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement:   | If not previously accomplished, remove the wiring connections from pins 51 and 52 in the electrical connectors of both Inertial Reference Units (IRU) in accordance with the procedures in Embraer Service Bulletin 170-34-0019 original issue dated 26 February 2007, or later revision approved by the Brazilian Agência Nacional de Aviação Civil (ANAC). |\n|                | Note: ANAC AD 2007-08-03 refers.                                                                                                                                                                                                                                                                                                                             |\n| Compliance:    | Within the next 18 months after the effective date of this Directive.                                                                                                                                                                                                                                                                                        |\n|                | This Airworthiness Directive becomes effective on 25 October 2007.                                                                                                                                                                                                                                                                                           |\n| Background:    | The ANAC has advised of reports of IRU failures which lead to an erroneous flight path angle (FPA) indication on both primary flight displays, with no alert to this condition to the crew. On ERJ-170 aircraft, FPA is considered as important as pitch and bank angle for piloting purposes.                                                               |\n|                | Since this condition affects flight safety, this Directive requires wiring changes which will improve IRU functionality.                                                                                                                                                                                                                                     |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n7 September 2007","sortOrder":0},{"sectionNumber":"AD/ERJ-170/12","sectionType":"part","heading":"AD/ERJ-170/12","content":"## AD/ERJ-170/12","sortOrder":1},{"sectionNumber":"Inertial Reference Unit Improvement","sectionType":"part","heading":"Inertial Reference Unit Improvement","content":"## Inertial Reference Unit Improvement","sortOrder":2},{"sectionNumber":"11/2007","sectionType":"part","heading":"11/2007","content":"## 11/2007","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific identified hardware defect. The scope remains precisely limited to the IRU wiring modification for the stated safety purpose."},"complexity_factors":["Single, specific mechanical action required (disconnect two pins)","Only one defined technical reference (Embraer Service Bulletin 170-34-0019)","No nested exceptions or conditional logic — applies to all ERJ-170 models uniformly","Clear, single deadline (18 months from effective date)","Short document with straightforward applicability and requirement sections","No cross-references to other legislation beyond the note about the Brazilian AD"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires all operators of Embraer ERJ‑170 aircraft to modify wiring on both Inertial Reference Units by disconnecting wires from pins 51 and 52, to prevent unannounced incorrect flight path angle indications on the pilots’ primary displays. Affected operators must comply within 18 months of 25 October 2007 (by April 2009) using Embraer Service Bulletin 170‑34‑0019 or an ANAC‑approved equivalent."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"Scope matches the instrument's stated intent: it requires a specific wiring change on all ERJ‑170 aircraft to mitigate IRU failures that caused erroneous flight path angle displays without alert (Applicability; Requirement; Background). There is no indication in the text that the applicability or substantive remedy was narrowed or expanded from that intent."},"complexity_factors":["Single, narrowly defined technical action: remove wiring from pins 51 and 52 of both IRUs (Requirement).","Applies to a single aircraft type but all units of that type — broad operator coverage for ERJ‑170 (Applicability).","Fixed compliance window: work must be done within 18 months of the effective date, creating scheduling and resource needs (Compliance).","Procedure tied to Embraer Service Bulletin 170‑34‑0019 and any later ANAC‑approved revision — dependency on manufacturer document and foreign regulator approval (Requirement).","Safety‑critical justification: addresses erroneous flight path angle indications without crew alert, which raises oversight and verification expectations (Background).","Regulatory enforcement via the Civil Aviation Safety Authority delegate: mandatory regulatory instrument with an effective date and signature."],"plain_english_summary":"Requires removal of wiring connections from pins 51 and 52 in the electrical connectors of both Inertial Reference Units on all Embraer ERJ‑170 aircraft, carried out per Embraer Service Bulletin 170‑34‑0019 (ANAC‑approved), within 18 months of 25 October 2007 (Requirement; Compliance). Owners/operators and maintenance organisations must fund and perform the work. The directive responds to ANAC reports that IRU failures produced erroneous flight‑path‑angle indications without crew alert and aims to improve IRU functionality (Background)."},"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-erj-170-12-inertial-reference-unit-improvement","history":"/api/acts/ad-erj-170-12-inertial-reference-unit-improvement/history","analysis":"/api/acts/ad-erj-170-12-inertial-reference-unit-improvement/analysis","conflicts":"/api/acts/ad-erj-170-12-inertial-reference-unit-improvement/conflicts","importantCases":"/api/acts/ad-erj-170-12-inertial-reference-unit-improvement/important-cases","documents":"/api/acts/ad-erj-170-12-inertial-reference-unit-improvement/documents"}}