{"id":"F2006B03429","name":"AD/B767/74 - Hydraulic Power - Ram Air Turbine Wiring","slug":"ad-b767-74-hydraulic-power-ram-air-turbine-wiring","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42970,"registerId":"commonwealth-F2006B03429-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B767/74 - Hydraulic Power - Ram Air Turbine Wiring","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)  \nBoeing 767 Series Aeroplanes\n\nAD/B767/74 Hydraulic Power \\- Ram Air Turbine Wiring 4/94\n\nApplicability: Model 767 series aeroplanes listed in Boeing Service Bulletin 767-29-0021 Revision 4 dated 12 May 1988.\n\nRequirement: Unless previously accomplished; replace the Ram Air Turbine (RAT) airspeed switch; cap and stow the wire between the RAT airspeed switch and the air/ground relay and then perform a functional test of the RAT deployment system; in accordance with Boeing Service Bulletin 767-29-0021 Revision 4 dated 12 May 1988.\n\nNote: FAA AD 94-01-02 Amdt 39-8784 refers.\n\nCompliance: Prior to 30 June 1995 or within 4000 hours time in service after 31 March 1994, whichever occurs later.\n\nBackground: The aircraft manufacturer has received reports of the RAT airspeed switch relay chattering during take-off and landing. Although the relay is designed and tested to cycle in excess of one million times, it was only expected to cycle once each flight, therefore the switch may fail due to excessive cycling.\n\nIf the failed switch remained in the open position the RAT may not automatically deploy, leading to a possible loss of hydraulic power. Compliance with this Directive is intended to prevent the inability to maintain hydraulic system power in the event that power is lost in both engines.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete airworthiness directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific technical requirement with clear mechanical actions (replace switch, cap wire, test system)","Only one defined applicability criterion (specific Boeing Service Bulletin)","Simple binary compliance deadline (date OR flight hours, whichever is later)","No nested exceptions, conditional logic, or cross-references to other legislation beyond a single FAA reference note","Background explanation provided in plain narrative form rather than technical legalese","Total length: approximately 200 words"],"plain_english_summary":"A safety order for Boeing 767 operators requires urgent repair of a vibrating/“chattering” Ram Air Turbine (RAT) airspeed switch and its wiring because premature wear can leave the RAT unable to auto‑deploy in an emergency. If the switch fails open, a dual‑engine loss could mean loss of hydraulic control. The directive—applying to aircraft covered by Boeing Service Bulletin 767‑29‑0021 Rev.4—mandates replacing or securing the switch/wiring and testing the system within the specified compliance window."},"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":2,"scope_assessment":{"changed":false,"description":"No change indicated. The Directive prescribes a specific corrective action for the models listed in the referenced Service Bulletin, sets a compliance deadline/flight‑hour alternative, and references an FAA AD; it does not expand or narrow applicability beyond that statement."},"complexity_factors":["Safety‑critical system: RAT deployment affects hydraulic power (Background).","Technical specificity: mandates replacement, capping/stowing of a specific wire and a functional test per Boeing SB 767‑29‑0021 Rev 4 (Requirement).","Limited applicability: only to models listed in the referenced Service Bulletin (Applicability).","Fixed compliance window with two alternatives (date or flight hours), which creates scheduling constraints for operators (Compliance).","Reliance on manufacturer documentation and an FAA AD reference for the corrective action (Requirement; Note)."],"plain_english_summary":"**What it does:** Requires operators of certain Boeing 767 aeroplanes to replace the Ram Air Turbine (RAT) airspeed switch, cap and stow the wire to the air/ground relay, and perform a functional RAT deployment test in accordance with Boeing Service Bulletin 767‑29‑0021 Rev 4.\n\n**Who it affects and why it matters:** Applies to the models listed in that Service Bulletin and must be done by 30 June 1995 or within 4,000 flight hours after 31 March 1994. The stated aim is to prevent RAT non‑deployment from switch failure, which could cause loss of hydraulic power."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b767-74-hydraulic-power-ram-air-turbine-wiring","history":"/api/acts/ad-b767-74-hydraulic-power-ram-air-turbine-wiring/history","analysis":"/api/acts/ad-b767-74-hydraulic-power-ram-air-turbine-wiring/analysis","conflicts":"/api/acts/ad-b767-74-hydraulic-power-ram-air-turbine-wiring/conflicts","importantCases":"/api/acts/ad-b767-74-hydraulic-power-ram-air-turbine-wiring/important-cases","documents":"/api/acts/ad-b767-74-hydraulic-power-ram-air-turbine-wiring/documents"}}