{"id":"F2005L03958","name":"AD/DO 328/7 - Relays 32HB and 36HB","slug":"ad-do-328-7-relays-32hb-and-36hb","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39826,"registerId":"commonwealth-F2005L03958-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Dornier 328 Series Aeroplanes","sectionType":"division","heading":"Dornier 328 Series Aeroplanes","content":"### Dornier 328 Series Aeroplanes\n\n| AD/DO 328/7 | Relays 32HB and 36HB | 1/2006 |\n| ----------- | -------------------- | ------ |\n\n| Applicability: | Model 328-100 aeroplanes with serial numbers 3005 to 3089 inclusive.                                                                                                                                                                    |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | If not previously accomplished, replace relays 32HB and 36HB part number (P/N) DON405M520U5NL with new relays 2504MY1 in accordance with the Accomplishment Instructions of Dornier Service Bulletins SB-328-21-218, dated 2 July 1997. |\n|                | Note: LBA AD 97-323 refers.                                                                                                                                                                                                             |\n| Compliance:    | Within 30 days after the effective date of this Directive.                                                                                                                                                                              |\n|                | This Airworthiness Directive becomes effective on 19 January 2006.                                                                                                                                                                      |\n| Background:    | The existing relay, when exposed to high electrical loads, overheats beyond its permissible operating range.                                                                                                                            |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n29 November 2005","sortOrder":0},{"sectionNumber":"AD/DO 328/7","sectionType":"part","heading":"AD/DO 328/7","content":"## AD/DO 328/7","sortOrder":1},{"sectionNumber":"Relays 32HB and 36HB","sectionType":"part","heading":"Relays 32HB and 36HB","content":"## Relays 32HB and 36HB","sortOrder":2},{"sectionNumber":"1/2006","sectionType":"part","heading":"1/2006","content":"## 1/2006","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive stays within the original safety remediation purpose: it addresses a specific electrical component (relay) that can overheat and requires its replacement. It does not broaden to additional parts, inspections, or aircraft models, nor introduce ongoing monitoring duties. Therefore the scope has not grown beyond the instrument’s stated corrective intent (as set out in the Applicability, Requirement and Background sections)."},"complexity_factors":["Single, specific requirement: one type of component replacement (relays 32HB and 36HB).","Narrow applicability: one model (Dornier 328-100) and a single contiguous serial-number range (3005–3089).","Single compliance timeframe: 30 days from effective date; no rolling or staged deadlines.","Cross-reference to a service bulletin (Dornier SB-328-21-218) and to LBA AD 97-323, but no multiple nested exceptions or alternative compliance paths.","Short document length and minimal defined terms; no continuing or recurring obligations beyond the one-time replacement."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Mandates a one-time hardware change on a specific set of Dornier 328-100 aeroplanes.  If it has not already been done, the directive requires replacement of two relays (identified as relays 32HB and 36HB, P/N DON405M520U5NL) with replacement relays P/N 2504MY1.\n- The replacement must be carried out in accordance with Dornier Service Bulletin SB-328-21-218 (Accomplishment Instructions) and completed within 30 days after the directive’s effective date (effective date: 19 January 2006).  The directive also refers to LBA AD 97-323.\n\n**Who this affects**\n\n- Owners and operators of Dornier 328-100 aeroplanes with serial numbers 3005 through 3089 inclusive (up to 85 aircraft).  They are legally required to comply with the directive.\n- Maintenance organisations and licensed engineers who perform the replacement according to the Dornier service bulletin and standard maintenance procedures.\n- Parts suppliers, to the extent replacement relays must be procured.\n\n**Why it matters (stated purpose and mechanical effect)**\n\n- The stated safety reason is that the existing relay (P/N DON405M520U5NL) can overheat when exposed to high electrical loads and exceed its safe operating range (see Background). Replacing the relay removes the component that can overheat and so reduces that specific electrical fire/thermal risk.\n\n**Operational consequences and implementation mechanics**\n\n- Who pays: the aircraft owner/operator pays for the replacement relay(s), associated labour and any downtime required to do the work (cost of parts + maintenance hours).\n- Who decides: the regulator has mandated the action; operators must arrange the work and document compliance. The service bulletin prescribes the technical steps; maintenance providers decide scheduling and method within those instructions.\n- Behaviour change required: operators must inspect records and, if the relays have not already been replaced, procure the new part(s) and carry out the replacement within the 30-day compliance window. Aircraft unable to meet the requirement may be grounded until compliance is shown, depending on operator procedures and regulator enforcement.\n\n**Costs, incentives and trade-offs**\n\n- Direct costs: purchase price of relay(s) and labour to install them, plus potential aircraft downtime. These are concentrated on the relatively small set of affected operators.\n- Opportunity cost: maintenance slots and resources diverted from other tasks to meet the 30‑day deadline.\n- Supply risk: if replacement relays are scarce, some operators may need to delay or source parts from alternate suppliers; this could extend downtime or raise costs.\n- Compliance burden: low procedural complexity (single component replacement) but time‑sensitive; documentation of compliance must be retained per normal continuing airworthiness rules.\n- No new ongoing regulatory obligations: the action is a one‑off replacement rather than continuing inspections or monitoring.\n\n**Implementation risk and practical points**\n\n- Implementation depends on availability of part P/N 2504MY1 and access to maintenance facilities within the 30‑day window.\n- The directive relies on the Dornier service bulletin for technical instructions; operators must follow those Accomplishment Instructions to demonstrate compliance.\n- The directive does not create discretionary exemptions in its text; compliance is mandatory for the listed serial numbers.\n\n**Source citations (where each point comes from)**\n\n- Applicability: model and serial numbers are listed under “Applicability.”\n- Requirement and method: replacement requirement and reference to Dornier Service Bulletin SB-328-21-218 are under “Requirement.”\n- Compliance timeframe: 30 days and effective date are under “Compliance.”\n- Safety rationale: the overheating problem is described under “Background.”\n\n(End of summary.)"},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive addressing a specific mechanical defect. It has not expanded beyond its original purpose of mandating relay replacement."},"complexity_factors":["Single, unambiguous requirement with no conditional branches or exceptions","Only one defined term (P/N = part number) used in common technical sense","No cross-references to other legislation or complex regulatory frameworks","Clear applicability criteria (specific serial number range)","Straightforward compliance deadline (30 days from effective date)","Total length is approximately 150 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's aviation regulator (CASA). It requires owners and operators of specific Dornier 328-100 aircraft to replace two electrical relays (components that switch electrical circuits on and off) within 30 days.\n\n**What the problem is:**\nThe existing relays (part numbers 32HB and 36HB) can overheat when handling high electrical loads, creating a fire risk or electrical system failure.\n\n**Who must act:**\nAnyone operating Dornier 328-100 aircraft with serial numbers 3005 through 3089.\n\n**What they must do:**\nReplace the faulty relays with improved ones (part number 2504MY1), following specific instructions in a Dornier service bulletin from 1997.\n\n**Why it matters:**\nThis prevents potential in-flight electrical failures or fires. Airworthiness Directives are legally binding — operators cannot fly the affected aircraft until the fix is done."}},"importantCases":[],"_links":{"self":"/api/acts/ad-do-328-7-relays-32hb-and-36hb","history":"/api/acts/ad-do-328-7-relays-32hb-and-36hb/history","analysis":"/api/acts/ad-do-328-7-relays-32hb-and-36hb/analysis","conflicts":"/api/acts/ad-do-328-7-relays-32hb-and-36hb/conflicts","importantCases":"/api/acts/ad-do-328-7-relays-32hb-and-36hb/important-cases","documents":"/api/acts/ad-do-328-7-relays-32hb-and-36hb/documents"}}