{"id":"F2008L03769","name":"AD/PREMIER/5 - Cabin Altitude and Barometric Pressure Switches","slug":"ad-premier-5-cabin-altitude-and-barometric-pressure-switches","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":75515,"registerId":"commonwealth-F2008L03769-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Hawker Beechcraft (Raytheon) 390 Series ","sectionType":"division","heading":"Hawker Beechcraft (Raytheon) 390 Series Aeroplanes","content":"### Hawker Beechcraft (Raytheon) 390 Series Aeroplanes\n\n| AD/PREMIER/5 | Cabin Altitude and BarometricPressure Switches | 12/2008 DM |\n| ------------ | ---------------------------------------------- | ---------- |\n\n| Applicability: | Model 390 aeroplanes, serial numbers RB-1 and RB-4 through RB-238 inclusive.                                                                                                                                                                                                                                     |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. If not previously accomplished, modify the cabin barometric pressure switch and cabin altitude high switch installations in accordance with Hawker Beechcraft Mandatory Service Bulletin SB 21-3899, original issue, dated May 2008.                                                                          |\n|                | 2 Perform a functional test of the switches and related systems in accordance with Part I - Ground Test Method in Paragraph 3 of the Accomplishment Instructions of SB 21-3899, original issue.                                                                                                                  |\n|                | Note 1: If, before the effective date of this Directive, the flight test method in Part II of the Accomplishment Instructions of SB 21-3899, original issue, was carried out, then the Requirement 2 functional test is not required provided it was done after the Requirement 1 modification was accomplished. |\n|                | 3. The flight test method described in Part II of the Accomplishment Instructions of SB 21-3899, original issue, is prohibited.                                                                                                                                                                                  |\n|                | Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2008-21-04, are considered acceptable for compliance with the equivalent Requirements of this Directive.                                              |\n|                | Note 2: FAA AD 2008-21-04 Amdt 39-15688 refers.                                                                                                                                                                                                                                                                  |\n| Compliance:    | For Requirement 1 - Within 25 hours time-in-service (TIS) after 20 October 2008 (the effective date of this Directive) or within 30 days after 20 October 2008, whichever occurs first.                                                                                                                          |\n|                | For Requirement 2 - Before further flight after the Requirement 1 modification of the cabin barometric pressure switch and cabin altitude high switch installations is accomplished.                                                                                                                             |\n|                | For Requirement 3 - After the effective date of this Directive.                                                                                                                                                                                                                                                  |\n|                | This Airworthiness Directive becomes effective on 20 October 2008.                                                                                                                                                                                                                                               |\n\n| Background: | The FAA has received reports of occurrences of incorrectly connected barometric switches. Additionally, the terminal used on the switches may be inadvertently dislodged while performing aeroplane maintenance in the pedestal area.                                                                                                                                                                                                            |\n| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n|             | This Directive requires the modification of the cabin barometric pressure switch and cabin altitude high switch to prevent them from becoming incorrectly connected or inadvertently disconnected, which may result in no CABIN ALT HI annunciation in the cockpit and no automatic deployment of the cabin oxygen masks. This failure could lead to incapacitation of the crew due to hypoxia with possible inability to control the aeroplane. |\n\n![](image.001.png)  \nCharles Lenarcic  \nDelegate of the Civil Aviation Safety Authority\n\n10 October 2008","sortOrder":0},{"sectionNumber":"AD/PREMIER/5","sectionType":"part","heading":"AD/PREMIER/5","content":"## AD/PREMIER/5","sortOrder":1},{"sectionNumber":"Cabin Altitude and BarometricPressure Sw","sectionType":"part","heading":"Cabin Altitude and BarometricPressure Switches","content":"## Cabin Altitude and Barometric  \nPressure Switches","sortOrder":2},{"sectionNumber":"12/2008 DM","sectionType":"part","heading":"12/2008 DM","content":"## 12/2008 DM","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":false,"description":"The Directive aligns with the FAA AD and the manufacturer Service Bulletin: it targets specified Model 390 serial numbers for a hardware modification and testing regimen to prevent switch misconnection/disconnection. It does not broaden applicability beyond the referenced SB/FAA AD; it adds a prohibition of the flight‑test method and allows FAA‑approved AMOCs, preserving the original safety‑focused scope."},"complexity_factors":["Narrow applicability: specific model and serial numbers reduce administrative complexity.","Technical modification requirement referencing Hawker Beechcraft Mandatory Service Bulletin SB 21-3899 (requires access to the SB to implement).","Testing protocol: requires a specific ground functional test (Part I) and expressly prohibits the SB's flight‑test method (Part II).","Interplay with FAA: later SB revisions are acceptable only if approved by FAA as an AMOC to FAA AD 2008-21-04, creating a cross‑jurisdictional compliance dependency.","Compliance timing: short mandatory windows (25 flight hours or 30 days for modification; test before next flight) create operational scheduling pressure.","Exception clause: Note 1 allows omission of Requirement 2 in limited circumstances, adding a conditional compliance path."],"plain_english_summary":"This Directive requires owners/operators of Hawker Beechcraft Model 390 aeroplanes (serial RB‑1 and RB‑4–RB‑238) to modify the cabin barometric pressure switch and cabin altitude high switch per Manufacturer Service Bulletin SB 21‑3899 and perform a ground functional test. CASA bans the flight‑test method in that SB but accepts FAA‑approved alternate methods. The rule aims to stop incorrect connections or dislodged switch terminals that could prevent CABIN ALT HI warnings and automatic oxygen‑mask deployment; owners/operators pay for and must schedule the work within short time limits."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific wiring/installation defect in specific aircraft models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Short, single-purpose directive with only 3 requirements","Clear cross-reference to external technical document (Service Bulletin SB 21-3899) rather than embedding complex technical specifications","Simple conditional logic (Note 1 exemption for prior flight testing)","Straightforward compliance timeline with binary choice (25 hours TIS vs 30 days)","Limited defined terms (only standard aviation terms like 'time-in-service' and 'TIS')","No nested exceptions or complex definitional sections"],"plain_english_summary":"This AD mandates a modification and functional test of the cabin barometric pressure switch and cabin altitude high switch on Hawker Beechcraft 390 jets (serial RB-1 and RB-4–RB-238), following Service Bulletin 21-3899, and prohibits using the SB’s \"flight test method\" to verify the repair. \n\nIt affects anyone operating those aircraft and must be done within 25 flight hours or 30 days after 20 Oct 2008 to prevent loss of cabin-altitude warnings and automatic oxygen deployment, which could cause crew hypoxia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-premier-5-cabin-altitude-and-barometric-pressure-switches","history":"/api/acts/ad-premier-5-cabin-altitude-and-barometric-pressure-switches/history","analysis":"/api/acts/ad-premier-5-cabin-altitude-and-barometric-pressure-switches/analysis","conflicts":"/api/acts/ad-premier-5-cabin-altitude-and-barometric-pressure-switches/conflicts","importantCases":"/api/acts/ad-premier-5-cabin-altitude-and-barometric-pressure-switches/important-cases","documents":"/api/acts/ad-premier-5-cabin-altitude-and-barometric-pressure-switches/documents"}}