{"id":"F2006B08594","name":"AD/CL-600/33 - Overwing Emergency Exit Hatches","slug":"ad-cl-600-33-overwing-emergency-exit-hatches","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51474,"registerId":"commonwealth-F2006B08594-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CL-600/33 - Overwing Emergency Exit Hatches","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)  \nBombardier (Canadair) CL-600 (Challenger) Series Aeroplanes\n\nAD/CL-600/33 Overwing Emergency Exit Hatches 6/99\n\nApplicability: Bombardier Inc. (formerly Canadair) CL-600-2B19 ‘Regional Jet’ aircraft, serial numbers 7003 through 7292.\n\nRequirement: Remove the insulation blankets surrounding the overwing emergency exit hatches in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-25-152 dated 26 December 1998.\n\nNote: Transport Canada Airworthiness Directive CF-99-01 refers.\n\nCompliance: Unless already accomplished, before 17 July 1999.\n\nThis Airworthiness Directive becomes effective on 17 June 1999.\n\nBackground: During maintenance within one hour after the last flight of the day, an operator experienced problems removing the overwing emergency exit hatches on three RJ aircraft. Investigation showed that the problem was due to freezing of moisture in the fibreglass/foam insulation installed in the aircraft.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD's scope as presented (remove insulation blankets surrounding overwing exit hatches on Bombardier CL-600-2B19 aircraft serial numbers 7003–7292) matches the stated problem and required remedy in the text. The instrument does not indicate any expansion or narrowing of that scope beyond the listed applicability and requirement."},"complexity_factors":["Narrow applicability limited to specific serial numbers (7003–7292) reduces scope complexity (Applicability).","Single, well-defined required action (removal of insulation blankets) simplifies operational requirements (Requirement).","Mandatory reliance on an external document (Bombardier Alert Service Bulletin A601R-25-152) adds dependency complexity because detailed steps are outside the AD text (Requirement).","Short compliance window between effective date (17 June 1999) and due date (17 July 1999) creates scheduling pressure for operators (Compliance; Effective date).","Limited detail in the AD about follow-up measures (e.g., replacement or thermal consequences) means implementers must consult the service bulletin or other guidance (Requirement)."],"plain_english_summary":"What this instrument changes (mechanical effect)\n\n- Requires removal of the fibreglass/foam insulation blankets that sit around the overwing emergency exit hatches on certain Bombardier CL-600-2B19 ‘Regional Jet’ aeroplanes. The removal must be done in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A601R-25-152 dated 26 December 1998 (Requirement).\n- Applies only to aircraft with serial numbers 7003 through 7292 (Applicability).\n- Sets a compliance deadline: unless the action has already been completed, the removal must be done before 17 July 1999; the directive is effective from 17 June 1999 (Compliance; Effective date).\n- The AD cross-references a Transport Canada Airworthiness Directive (CF-99-01) but does not add other measures (Note).\n\nWhy the change was ordered (stated rationale)\n\n- The background given is that maintenance crews experienced difficulty removing overwing exit hatches on three of these aircraft during maintenance performed within one hour after the last flight of the day. An investigation attributed the problem to freezing of moisture in the fibreglass/foam insulation around the hatches (Background). The AD therefore directs removal of those insulation blankets as the prescribed mitigation (Requirement).\n\nWho must act, who decides, and who bears the burden\n\n- The affected parties are operators of Bombardier CL-600-2B19 aeroplanes with serial numbers 7003–7292; those operators must arrange for and carry out the removal as required (Applicability; Requirement).\n- The Civil Aviation Safety Authority issues the directive; compliance is mandatory for the named aircraft (Effective date; Compliance).\n- The operators incur the operational and maintenance effort and any associated costs of performing the removal and following the manufacturer’s Accomplishment Instructions (Requirement). The AD text does not specify compensation, replacements, or follow-up modifications.\n\nImplementation mechanics and immediate effects\n\n- Operators must follow the Bombardier Alert Service Bulletin A601R-25-152 (Requirement). The AD itself specifies the action (remove the insulation blankets) but relies on the referenced service bulletin for the detailed steps (Requirement).\n- The AD provides a short compliance window (about one month from the effective date), which concentrates scheduling and maintenance activity into that period unless already done (Compliance; Effective date).\n\nCompliance burden, discre­tion and risks\n\n- Compliance requires maintenance work of an operational nature (removal of insulation blankets) and adherence to the referenced manufacturer instructions; the AD text does not specify further discretionary options or alternative mitigations (Requirement).\n- The AD does not state whether removed insulation must be replaced, altered, or how thermal or acoustic effects are to be managed; those details would be in the referenced service bulletin or further airworthiness instructions (Requirement).\n- A short compliance window increases the need for operators to re-prioritise maintenance slots and to ensure record-keeping that the action has been completed before the prescribed date (Compliance).\n\nTrade-offs and opportunity costs (mechanical, not evaluative)\n\n- The directive imposes immediate maintenance work on a defined fleet subset, which consumes labour and time that could otherwise be used for other maintenance. The AD text does not quantify those costs or require compensating measures (Compliance; Requirement).\n\nReference notes\n\n- The AD expressly cites Bombardier Alert Service Bulletin A601R-25-152 (dated 26 December 1998) for how to perform the removal (Requirement), and notes Transport Canada AD CF-99-01 as a related document (Note).\n\nSource citations: applicability, requirement, compliance, note, effective date, and background language taken verbatim from the AD/CL-600/33 text provided."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect identified in a particular aircraft series. It has not expanded beyond its original purpose of ensuring emergency exit operability."},"complexity_factors":["Single, specific technical requirement (remove insulation blankets)","Narrow applicability (one aircraft model, specific serial number range)","No defined terms section — uses plain technical language","Single cross-reference to manufacturer service bulletin and Canadian directive","Clear, unconditional compliance deadline","Short document (under 200 words of substantive text)"],"plain_english_summary":"This is a **safety order** (called an \"Airworthiness Directive\") issued by Australia's aviation safety regulator for a specific type of aircraft.\n\n**What it does:**\n- Orders airlines and aircraft owners to **remove insulation blankets** from around the emergency exit hatches on certain Bombardier Regional Jet aircraft\n- The insulation can trap moisture, which freezes and **jams the emergency exits shut** — a serious danger if passengers need to evacuate quickly\n\n**Who it affects:**\n- Owners and operators of **Bombardier CL-600-2B19 'Regional Jet' aircraft** with serial numbers 7003 through 7292\n- This covers approximately 290 specific aircraft\n\n**Why it matters:**\n- Emergency exits must open instantly during an evacuation. Frozen insulation had already caused exits to stick on three aircraft during maintenance checks\n- The fix is mandatory — operators must comply by **17 July 1999** unless they've already done the work\n- The directive references a manufacturer service bulletin and a Canadian aviation directive, showing how safety regulators worldwide coordinate on aircraft issues\n\n**Key deadline:** The order takes effect on 17 June 1999, with full compliance required by 17 July 1999."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cl-600-33-overwing-emergency-exit-hatches","history":"/api/acts/ad-cl-600-33-overwing-emergency-exit-hatches/history","analysis":"/api/acts/ad-cl-600-33-overwing-emergency-exit-hatches/analysis","conflicts":"/api/acts/ad-cl-600-33-overwing-emergency-exit-hatches/conflicts","importantCases":"/api/acts/ad-cl-600-33-overwing-emergency-exit-hatches/important-cases","documents":"/api/acts/ad-cl-600-33-overwing-emergency-exit-hatches/documents"}}