{"id":"F2006B09171","name":"AD/DHC-8/16 Amdt 1 - Engine Bleed Air","slug":"ad-dhc-8-16-amdt-1-engine-bleed-air","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52916,"registerId":"commonwealth-F2006B09171-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/16 Amdt 1 - Engine Bleed Air","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 (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\nAD/DHC-8/16\n\nAmdt 1\n\n  \n\nEngine Bleed Air 3/94 DM\n\nApplicability: DHC-8-100 series aircraft not incorporating de Havilland Inc. modifications #8/1155 and #8/1820.\n\nRequirement: This Directive requires the DHC-8-100 Series Aircraft Flight Manuals to be amended in accordance with Para 1(a) of Transport Canada AD CF-91-32R1 to prohibit the use of engine BLEEDS-ON during take-off and landing.\n\nNote 1: Later AFM amendments to those listed in Transport Canada AD CF-91- 32R1 meet the Requirement of this AD.\n\nNote 2: Incorporation of both de Havilland Inc. modifications #8/1155 (SB 8-21-29) and #8/1820 (SB 8-21-53) is terminating action for the requirements of this AD.\n\nNote 3: Upon incorporation of the respective modifications BLEEDS-ON take-off and landing operations may be conducted in accordance with Supplement 21, Issue 2 of the AFM.\n\nCompliance: Unless previously accomplished, prior to 20 January 1994.\n\nNote: Compliance with the original issue of this AD satisfies the requirements of this amendment.\n\nBackground: The requirement reflects advice from Transport Canada that failure of a L.H. engine during a BLEEDS-ON take-off may result in the remaining engine bleed system moving to maximum bleed position.\n\nThis condition will result in a reduction of uptrim power available to that engine.\n\nTerminating action for this AD is provided by incorporation of de Havilland Inc. modifications #8/1155 and #8/1820.","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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope unchanged from the existing AD: this amendment reiterates the AFM prohibition and compliance deadline rather than expanding applicability. The AD confirms that compliance with the original issue satisfies the amendment and that installing modifications #8/1155 and #8/1820 is the terminating action (Notes; Compliance)."},"complexity_factors":["Narrow applicability: affects only DHC-8-100 series aircraft lacking de Havilland modifications #8/1155 and #8/1820 (Applicability).","Prescriptive operational change: requires a specific AFM amendment prohibiting BLEEDS‑ON during take-off and landing (Requirement).","Fixed compliance deadline: imposes a hard date for operators to comply, creating scheduling and administrative burden (Compliance: prior to 20 January 1994).","Clear terminating action: incorporation of the two listed modifications removes the AFM restriction, providing a retrofit pathway (Notes 2–3).","Technical safety rationale: ties directly to a specific failure mode (LH engine failure with BLEEDS‑ON) that may reduce uptrim power on the remaining engine (Background).","Low regulator discretion: directive is prescriptive rather than discretionary, so implementation choices for regulators are limited (Requirement/Compliance)."],"plain_english_summary":"This airworthiness directive requires operators of Bombardier (De Havilland) DHC-8-100 aircraft that have not installed de Havilland modifications #8/1155 and #8/1820 to amend their Aircraft Flight Manual to prohibit using engine BLEEDS‑ON during take-off and landing. The change must be implemented by 20 January 1994. Transport Canada advised that a left‑engine failure with BLEEDS‑ON can drive the remaining engine bleed to maximum, reducing available uptrim power; installing the two modifications removes the restriction."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) to an existing Airworthiness Directive. The scope remains tightly focused on the original safety issue (engine bleed air management during critical flight phases). The amendment appears to update reference documents or clarify compliance pathways without expanding the substantive scope beyond the DHC-8-100 series and the specific bleed air prohibition."},"complexity_factors":["Single, specific aircraft type and series (DHC-8-100)","Clear applicability test (absence of two specific modifications)","Single requirement with straightforward compliance action (manual amendment)","Only 3 short notes and brief background section","No nested definitions, cross-references to other Australian legislation, or conditional logic chains","References to external Canadian aviation safety document (Transport Canada AD CF-91-32R1) but incorporates by reference rather than reproducing complex text"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Bombardier DHC-8-100 aircraft (without factory mods 8/1155 and 8/1820) to amend their Aircraft Flight Manuals to prohibit using engine bleed air during take‑off and landing. The ban addresses a safety risk: if the left engine fails with bleeds on, the remaining engine’s bleed system can surge and steal thrust when it’s most needed. Installing the two mods restores normal operations."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-16-amdt-1-engine-bleed-air","history":"/api/acts/ad-dhc-8-16-amdt-1-engine-bleed-air/history","analysis":"/api/acts/ad-dhc-8-16-amdt-1-engine-bleed-air/analysis","conflicts":"/api/acts/ad-dhc-8-16-amdt-1-engine-bleed-air/conflicts","importantCases":"/api/acts/ad-dhc-8-16-amdt-1-engine-bleed-air/important-cases","documents":"/api/acts/ad-dhc-8-16-amdt-1-engine-bleed-air/documents"}}