{"id":"F2006B10912","name":"AD/JETSTREAM/43 - Flying Controls - Audible Warning","slug":"ad-jetstream-43-flying-controls-audible-warning","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56452,"registerId":"commonwealth-F2006B10912-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/JETSTREAM/43 - Flying Controls - Audible Warning","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  British Aerospace BAe 3100 (Jetstream) Series Aeroplanes\n\n \n\nAD/JETSTREAM/43 Flying Controls - Audible Warning 6/91 T\n\nApplicability: All Jetstream series 3100 aircraft.\n\n \n\nRequirement: Action in accordance with the British Aerospace Alert Service Bulletin 27-A-JA 910340.\n\n \n\nNote 1: This Alert SB is classified MANDATORY by the CAA (UK). Note 2: CAA (UK) Airworthiness Directive 017-03-91 also refers.\n\nCompliance: Prior to 15 April 1991.\n\n \n\nBackground:  Action in accordance with the requirement document is necessary in order to avoid the possibility of uncommanded nose-down pitching motion of the aircraft when conducting landings with the wing flaps extended to 50 degrees and with ice present on the tailplane.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive for a specific aircraft type. It has not expanded beyond its original purpose of addressing the specific icing-related pitch control issue."},"complexity_factors":["Single, specific aircraft type (Jetstream 3100 series)","One clear requirement: comply with referenced service bulletin","No defined terms section","No nested conditional logic or exceptions","Simple structure: Applicability → Requirement → Compliance → Background","Cross-references only to external documents (UK service bulletin and AD), not internal legislative provisions","Length: approximately 150 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive** — essentially a mandatory safety order issued by Australia's aviation safety regulator (CASA) for a specific type of aircraft.\n\n**What it does:**\nIt requires owners and operators of **British Aerospace Jetstream 3100 series aircraft** to carry out a specific safety modification. The work must follow instructions in a British Aerospace **Alert Service Bulletin** (a manufacturer's urgent technical notice).\n\n**Why it matters:**\nWithout this fix, there's a dangerous risk: when landing with the wing flaps fully extended (50 degrees) **and** ice on the tailplane, the aircraft could suddenly pitch nose-down unexpectedly. This \"uncommanded nose-down pitching motion\" could cause loss of control during landing — a critical phase of flight.\n\n**Who must comply:**\nAnyone operating these specific Jetstream aircraft in Australia.\n\n**When:**\nThe work had to be completed before **15 April 1991**.\n\n**Key point:** This directive references UK safety standards (the CAA UK classified the manufacturer's bulletin as mandatory), showing how Australia harmonises its aviation safety rules with international standards."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD’s scope remains a targeted, type-specific mandatory requirement: it applies to all BAe 3100 (Jetstream) series aircraft and requires implementation of British Aerospace Alert Service Bulletin 27-A-JA 910340 by the stated compliance date to address the specified nose-down pitching hazard when landing with flaps at 50° and tailplane ice present. There is no indication in the text that the AD changes that scope from the instrument’s stated purpose (Applicability; Requirement; Compliance; Background)."},"complexity_factors":["Single, clear technical requirement tied to a single manufacturer Alert Service Bulletin (Requirement)","Applicability covers an entire aircraft type class (all Jetstream series 3100) but does not require individual case assessment (Applicability)","External dependency on the Alert Service Bulletin for technical steps creates an implementation linkage but the AD does not contain technical detail (Requirement)","Fixed compliance deadline concentrates logistical and maintenance planning (Compliance)","Regulatory cross-reference to U.K. CAA mandatory classification and a U.K. AD adds interstate alignment but not procedural complexity (Note 1; Note 2)"],"plain_english_summary":"What this instrument does (mechanical change first)\n\n- It requires operators of British Aerospace BAe 3100 (Jetstream) series aeroplanes to carry out the work specified in British Aerospace Alert Service Bulletin 27-A-JA 910340. (Requirement)\n- The work must be completed before 15 April 1991. (Compliance)\n\nWho it affects\n\n- The AD applies to all Jetstream series 3100 aircraft. That means the owners/operators of every aircraft in that type class are the parties required to take the action set out in the Alert Service Bulletin. (Applicability; Requirement)\n\nWhy it matters (official claim and what that implies)\n\n- The document states the required action is necessary to avoid the possibility of an uncommanded nose-down pitching motion during landings when the wing flaps are set to 50 degrees and ice is present on the tailplane. This is the safety rationale provided for the mandated work. (Background)\n- The Alert Service Bulletin is also identified as MANDATORY by the U.K. Civil Aviation Authority, and a related U.K. AD is referenced. Those references indicate the requirement aligns with the U.K. regulator’s mandatory guidance. (Note 1; Note 2)\n\nWho pays, who decides, and what changes in behaviour\n\n- The AD places the obligation on the operator/owner of each affected Jetstream 3100 to arrange and fund whatever inspections, modifications or repairs are specified in the Alert Service Bulletin. (Applicability; Requirement)\n- Regulators (the Civil Aviation Safety Authority issuing the AD and the referenced U.K. CAA classification) decide the mandatory nature and timing of the action. (Requirement; Note 1)\n- Operators must schedule maintenance or modification work before the stated compliance date, and until the work is done they will face the operational safety constraint described (risk during landings with flaps at 50° and tailplane ice). (Compliance; Background)\n\nCosts, incentives, trade-offs and implementation risks (mechanical description, not judgement)\n\n- Direct costs and downtime: The AD forces operators to incur the costs of performing the service-bulletin work and any associated aircraft downtime. The AD does not quantify those costs. (Requirement)\n- Supply and skill constraints: Compliance may require parts, specialised labour, or tooling specified by the Alert Service Bulletin. The AD references that external document as the technical instruction to follow; the AD itself does not detail the steps. That creates dependency on the manufacturer’s bulletin for the precise compliance tasks. (Requirement)\n- Deadline risk: The fixed compliance date (prior to 15 April 1991) concentrates demand for maintenance resources ahead of that date and creates a risk that some operators may struggle to complete the work in time. (Compliance)\n- Regulatory alignment and duplication: The AD cites the U.K. CAA classification and a U.K. Airworthiness Directive. Operators dealing with multiple regulators will follow the technical instruction once, but the AD formalises the obligation under the Commonwealth instrument. (Note 1; Note 2)\n\nImplementation and compliance burden\n\n- The AD requires following an external technical document (the Alert Service Bulletin). That means compliance efforts consist of obtaining and implementing the bulletin’s instructions. The CSA AD does not itself describe the technical steps or costs. (Requirement)\n- Compliance is mandatory for all affected aircraft by the date given; failure to comply would leave the operator out of step with the AD’s legal obligation. (Applicability; Compliance)\n\nConcise restatement of purpose and mechanism\n\n- Mechanism: mandatory implementation of a manufacturer’s Alert Service Bulletin across the entire BAe 3100 fleet, to be completed by a fixed date. (Requirement; Applicability; Compliance)\n- Stated purpose: to prevent a possible uncommanded nose-down pitching motion on landing with flaps at 50° in the presence of tailplane ice. (Background)\n\nSource citations: Applicability; Requirement; Compliance; Background; Note 1; Note 2."}},"importantCases":[],"_links":{"self":"/api/acts/ad-jetstream-43-flying-controls-audible-warning","history":"/api/acts/ad-jetstream-43-flying-controls-audible-warning/history","analysis":"/api/acts/ad-jetstream-43-flying-controls-audible-warning/analysis","conflicts":"/api/acts/ad-jetstream-43-flying-controls-audible-warning/conflicts","importantCases":"/api/acts/ad-jetstream-43-flying-controls-audible-warning/important-cases","documents":"/api/acts/ad-jetstream-43-flying-controls-audible-warning/documents"}}