{"id":"F2005L03926","name":"AD/DO 328/33 - Cabin Pressure Control System","slug":"ad-do-328-33-cabin-pressure-control-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":39750,"registerId":"commonwealth-F2005L03926-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 328/33 | Cabin Pressure Control System | 1/2006 |\n| ------------ | ----------------------------- | ------ |\n\n| Applicability: | Model 328-100 aeroplanes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | For aeroplanes, serial number (S/N) 3005 to 3086 inclusive, without a placard installed on the Cabin Pressure Control System (CPCS) panel in accordance with the Accomplishment Instructions of Dornier Service Bulletins SB-328-21-225, dated27 June 1997, install a placard in accordance with SB-328-21-225.                                                                                                                                                                                       |\n|                | Note 1: For S/Ns after 3086, SB-328-21-225 was incorporated during production.                                                                                                                                                                                                                                                                                                                                                                                                                        |\n|                | Note 2: Fitment of a modified Pressurisation Control Unit (PCU) part number 22260A030201 in accordance with the Accomplishment Instructions ofSB-328-21-261, dated 27 January 1999, is an optional alternate method of compliance for this Directive for aeroplanes S/N 3005 to 3086 inclusive. Additionally, fitment of a modified PCU in accordance with SB-328-21-261 to aeroplanes 3087 to 3098 inclusive, 3100, 3101, 3104, 3106, 3107, 3109, 3110, 3112, 3113, 3115, 3117 and 3119 is optional. |\n|                | Note 3: Placards installed in accordance with SB-328-21-225 or during production must be removed when the modified PCU is fitted.                                                                                                                                                                                                                                                                                                                                                                     |\n|                | Note 4: LBA AD 1997-242/3 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 German Luftfahrt-Bundesamt(LBA) has advised during flight above FL250, when the pressurisation control is set to the MAN mode, a pressurisation drop of approximately 1 000ft may occur for a short time if the pressurisation control is switched back to manual mode.                                                                                                                                                                                                                           |\n\n|     | Initially, earlier issues of the LBA Airworthiness Directive required placarding of the CPCS panel on aeroplanes S/N 3005 to 3086, this is reflected in this Directive. However, in late 1999 the LBA introduced the fitment of a modified PCU(SB-328-21-261), as an optional alternate method of compliance (AMOC) to the placarding of the CPCS panel. The AMOC is equally applicable to aeroplanes S/N 3005 to 3086, which were placarded in accordance with SB-328-21-255, and to later aeroplanes which were placarded during production. Following installation of the modified PCU the placard may be removed from the CPCS panel. This information is reflected in Notes 2 and 3 of this Directive. |\n| --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n1 December 2005","sortOrder":0},{"sectionNumber":"AD/DO 328/33","sectionType":"part","heading":"AD/DO 328/33","content":"## AD/DO 328/33","sortOrder":1},{"sectionNumber":"Cabin Pressure Control System","sectionType":"part","heading":"Cabin Pressure Control System","content":"## Cabin Pressure Control System","sortOrder":2},{"sectionNumber":"1/2006","sectionType":"part","heading":"1/2006","content":"## 1/2006","sortOrder":3}],"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive reflects a change from the earlier requirement (placarding only) to allow an alternate method of compliance: fitment of a modified PCU introduced by the LBA in late 1999. Notes 2 and 3 incorporate that AMOC and the requirement to remove the placard after PCU installation; the Directive therefore expands compliance pathways relative to the original placarding-only intent."},"complexity_factors":["Narrow applicability tied to specific serial numbers (S/N 3005–3086) plus production-fitted exception (Note 1).","Two compliance options: placard installation per SB-328-21-225 or optional AMOC by fitting modified PCU per SB-328-21-261 (Note 2).","Interaction between measures: placard must be removed if modified PCU is later fitted (Note 3).","Short compliance period: action required within 30 days of effective date.","Dependence on external technical documents and foreign authority reference (Service Bulletins and LBA AD 1997-242/3) for detailed instructions.","Operational trigger and technical cause described (Background) but remedial action is limited and specific, reducing scope of regulatory discretion."],"plain_english_summary":"This Airworthiness Directive requires operators of Dornier 328‑100 aeroplanes S/N 3005–3086 to install a warning placard on the Cabin Pressure Control System panel per Dornier Service Bulletin SB‑328‑21‑225 within 30 days, unless they fit a modified Pressurisation Control Unit (PCU) per SB‑328‑21‑261 as an approved alternate method. It responds to reports that above FL250, switching pressurisation to MAN and back can momentarily lower cabin pressure by about 1,000 ft."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific technical issue with a specific aircraft type. The scope remains tightly focused on the cabin pressure control system anomaly identified by German authorities. The inclusion of an alternative compliance method (modified PCU) and extended applicability to later serial numbers represents standard regulatory flexibility rather than scope creep."},"complexity_factors":["Multiple serial number ranges with different treatment (3005–3086 vs 3087–3119 with specific exclusions)","Conditional logic: primary requirement (placard) vs optional alternative compliance method (modified PCU)","Cross-references to two German service bulletins (SB-328-21-225 and SB-328-21-261) and one German airworthiness directive (LBA AD 1997-242/3)","Nested conditions: if modified PCU fitted, placard must be removed; modified PCU optional for some serial numbers, mandatory alternative for others","Technical aviation terminology requiring domain knowledge (CPCS, PCU, FL250, AMOC)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety notice issued by Australia's aviation regulator (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners/operators of certain Dornier 328-100 aeroplanes to install a warning placard (a physical label) on the cabin pressure control panel. This placard warns pilots about a dangerous quirk: if they switch the pressurisation system back to manual mode above 25,000 feet, the cabin altitude can suddenly drop by about 1,000 feet — potentially causing passenger discomfort or safety issues.\n\n**Who it affects:**\n- Specifically: Dornier 328-100 planes with serial numbers 3005 through 3086\n- **Exception:** Planes built after serial number 3086 already have the placard from the factory, so they don't need to do anything\n\n**Alternative fix:**\nInstead of installing the placard, operators can optionally install a modified pressurisation control unit (PCU part number 22260A030201). If they do this upgrade, they must remove any existing placard. This modified part is also optionally available for some later serial numbers (3087–3119, with specific exclusions).\n\n**When it had to be done:**\nWithin 30 days of 19 January 2006.\n\n**Why it matters:**\nUncontrolled cabin pressure changes at high altitude can cause ear pain, hypoxia (lack of oxygen), or in extreme cases, structural stress. This directive closes a safety gap identified by German aviation authorities where manual mode switching could trigger a sudden depressurisation event."}},"importantCases":[],"_links":{"self":"/api/acts/ad-do-328-33-cabin-pressure-control-system","history":"/api/acts/ad-do-328-33-cabin-pressure-control-system/history","analysis":"/api/acts/ad-do-328-33-cabin-pressure-control-system/analysis","conflicts":"/api/acts/ad-do-328-33-cabin-pressure-control-system/conflicts","importantCases":"/api/acts/ad-do-328-33-cabin-pressure-control-system/important-cases","documents":"/api/acts/ad-do-328-33-cabin-pressure-control-system/documents"}}