{"id":"F2006B02493","name":"AD/AS 355/39 - Electric Hoist Installation","slug":"ad-as-355-39-electric-hoist-installation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41749,"registerId":"commonwealth-F2006B02493-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AS 355/39 - Electric Hoist Installation","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)  \nEurocopter AS 355 (Twin Ecureuil) Series Helicopters\n\nAD/AS 355/39 Electric Hoist Installation 1/92\n\nApplicability: All AS 355 helicopters as specified in the requirement document.\n\nRequirement: 1. If not already incorporated, modify the hoist in accordance with paragraph 1 C 1 of Aerospatiale Service Bulletin 25-30.\n\n2. Carry out an Electrical Bonding Check in accordance with paragraph 1 C 3 of Aerospatiale Service Bulletin 25-30.\n\nNote 1: Do NOT re-install the pyrotechnic cable cutting squib in accordance with Aerospatiale SB 25-30. AD/SUPP/12 refers.\n\nNote 2: DGAC AD 91-164-042(B) also refers. Note 3: AD/SUPP/13 also refers.\n\nCompliance: Requirement 1. Within 50 hours time in service after 12 January 1992, but no later than 12 March 1992.\n\nRequirement 2. Within 50 hours time in service after 12 January 1992, but no later than 12 March 1992, and thereafter at intervals not exceeding 24 months; and on each occasion following removal and reinstallation of the hoist or the hoist arm to the aircraft.\n\nBackground: A number of inadvertent firings of the pyrotechnic cable cutting device on a variety of helicopter electric hoists resulted in the removal of the pyrotechnic device from all hoists when used for personnel winching pending further investigation (AD/SUPP/12 refers). The pyrotechnic cable cut device is however still required to be fitted to hoists when hoisting cargo.\n\nAD/SUPP/13 requires modification and testing of the bonding between the component parts of the Air Equipment Hoist P/No 76370 (all variants). Compliance with this AD (AD/AS 355/39) will improve the bonding between the hoist and the aircraft, and reduce the likelihood of un-commanded cable cuts when the pyrotechnic device is fitted for cargo winching. Note however that fitment of the pyrotechnic device for personnel winching is still prohibited by AD/SUPP/12 pending further investigation.","sortOrder":0}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow scope—safety modifications for electric hoists on AS 355 helicopters. The background explains the safety context but does not expand the directive's application beyond the original technical purpose."},"complexity_factors":["Short, single-purpose directive (2 requirements only)","Heavy reliance on external technical documents (Aerospatiale Service Bulletin 25-30) without reproducing their content","Multiple cross-references to other directives (AD/SUPP/12, AD/SUPP/13, DGAC AD 91-164-042(B))","Conditional compliance timing (50 hours time in service OR fixed calendar date, whichever comes first)","Ongoing recurring obligation (24-month intervals plus trigger-based checks on removal/reinstallation)","Specific exclusion (pyrotechnic device prohibition for personnel winching despite being mentioned in referenced bulletin)"],"plain_english_summary":"This directive requires owners/operators of Eurocopter AS 355 helicopters fitted with electric hoists to modify the hoist and improve electrical bonding, and to carry out initial and recurring electrical safety checks, to prevent unintended firing of pyrotechnic cable cutters. \n\nIt preserves the prohibition on using such cutters for personnel winching and targets accidental cable release during cargo operations to reduce the risk of dropped loads or injury."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This directive is narrowly focused on correcting a specific safety problem (inadvertent firings of the pyrotechnic cable cutter) by requiring a hoist modification and electrical bonding checks. It does not extend the subject matter beyond that original safety purpose; instead it sets a required technical fix, an inspection regime, and maintains a separate operational prohibition on using the pyrotechnic device for personnel winching. There is no indication in the text that the AD broadens the regulated activities beyond that initial safety response."},"complexity_factors":["Short directive with two core technical requirements (modification + bonding check).","Hard compliance deadlines tied to a specific calendar date (50 hours after 12 Jan 1992, no later than 12 Mar 1992).","Recurring inspection requirement (every 24 months) plus inspection-triggering event (removal/reinstallation of hoist or hoist arm).","Dependence on external technical documents: Aerospatiale Service Bulletin 25-30 (paragraphs 1 C 1 and 1 C 3).","Cross-references to other airworthiness directives (AD/SUPP/12, AD/SUPP/13) and a foreign AD (DGAC AD 91-164-042(B)).","Operational prohibition in a separate AD (pyrotechnic squib prohibited for personnel winching) creates an interdependent constraint between ADs."],"plain_english_summary":"**What this directive does (mechanical changes)**\n\n- Requires modification of the electric hoist fitted to Eurocopter AS 355 (Twin Ecureuil) series helicopters by carrying out the change described at paragraph 1 C 1 of Aerospatiale Service Bulletin 25-30 (see Requirement 1).\n- Requires an Electrical Bonding Check of the hoist installation in accordance with paragraph 1 C 3 of Aerospatiale Service Bulletin 25-30 (see Requirement 2).\n- Prohibits reinstalling the pyrotechnic cable-cutting squib for personnel winching (Note 1) — the pyrotechnic device remains removed for personnel winching until further notice, but may still be required for cargo hoisting.\n\n**Who must act**\n\n- Helicopter operators and maintenance organisations responsible for Eurocopter AS 355 helicopters that have the hoist installed must carry out the modification and the electrical bonding checks.\n\n**When the work must be done**\n\n- The modification (Requirement 1) must be completed within 50 hours time-in-service after 12 January 1992, and in any event no later than 12 March 1992.\n- The initial Electrical Bonding Check (Requirement 2) has the same 50‑hour / 12 March 1992 deadline, and thereafter must be repeated at intervals not exceeding 24 months and each time the hoist or hoist arm is removed and reinstalled.\n\n**Why the rule exists (official rationale and effect)**\n\n- The directive cites multiple inadvertent firings of pyrotechnic cable-cut devices on helicopter hoists. The official purpose is to improve the electrical bonding between the hoist and the airframe so as to reduce the likelihood of uncommanded (unexpected) cable-cuts when the pyrotechnic device is fitted for cargo winching (Background).\n\n**Immediate practical consequences and operational effects**\n\n- Operators bear the direct costs of performing the hoist modification and the recurring bonding checks (parts, labour, aircraft downtime).\n- Maintenance organisations must follow the Aerospatiale Service Bulletin paragraphs specified (the rule depends on a manufacturer’s service instruction for the technical steps).\n- The pyrotechnic cutting device must remain out of service for personnel winching (per AD/SUPP/12), which constrains how helicopters may be used during personnel winching tasks until that separate directive is lifted or changed.\n\n**Implementation, compliance and oversight notes**\n\n- The AD cross-references other directives and an overseas airworthiness directive (DGAC AD 91-164-042(B)) and two supplementary ADs (AD/SUPP/12 and AD/SUPP/13). Compliance therefore requires checking and following those related documents where they apply (Notes 1–3).\n- The recurring inspection interval (24 months) and the additional requirement to test after any removal/reinstallation create an ongoing maintenance obligation rather than a one-off fix.\n\n**Trade-offs, incentives and likely impacts**\n\n- The stated safety benefit (reduced risk of uncommanded cuts) is achieved by a technical modification plus periodic checks. The cost of that safety improvement is concentrated on operators and maintenance providers (parts, labour and downtime). The benefit — fewer inadvertent firings — is distributed across crews, passengers, and the public.\n- Reliance on a manufacturer service bulletin concentrates technical decisions in the hands of the type certificate holder and the maintenance organisations that implement it. That creates a straightforward compliance path but gives weight to the bulletin’s technical scope and timing.\n- The continued prohibition on using the pyrotechnic cutter for personnel winching changes operational choices: operators must use alternative procedures or equipment for personnel winching until the prohibition is lifted.\n\n(References: Requirement 1; Requirement 2; Note 1; Background.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-as-355-39-electric-hoist-installation","history":"/api/acts/ad-as-355-39-electric-hoist-installation/history","analysis":"/api/acts/ad-as-355-39-electric-hoist-installation/analysis","conflicts":"/api/acts/ad-as-355-39-electric-hoist-installation/conflicts","importantCases":"/api/acts/ad-as-355-39-electric-hoist-installation/important-cases","documents":"/api/acts/ad-as-355-39-electric-hoist-installation/documents"}}