{"id":"F2006B09249","name":"AD/DHC-8/9 - Flap Track No.5 Fail Safe Straps","slug":"ad-dhc-8-9-flap-track-no-5-fail-safe-straps","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53176,"registerId":"commonwealth-F2006B09249-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/9 - Flap Track No.5 Fail Safe Straps","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)  Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\n \n\nAD/DHC-8/9 Flap Track No.5 Fail Safe Straps 10/89\n\nApplicability: Serial number 1 through 119.\n\n \n\nRequirement: Action in accordance with Boeing Canada DHC-8 Service Bulletin No. 8-57-10 dated 31 March 1989.\n\n \n\nNote: Transport Canada AD CF-89-02 refers.\n\n \n\nCompliance: Within 500 hours time in service after 5 October 1989, or prior to 5 January 1990, whichever occurs first.\n\n \n\nBackground: Some fatigue failures have occurred on subject straps because of incorrect installation.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text of the directive specifies the affected population (serial numbers 1–119), the required action (follow the named service bulletin), the compliance window, and the stated reason (fatigue failures from incorrect installation). It does not indicate any amendment, extension, narrowing, or other alteration of an earlier scope within the document itself, so there is no evidence here that the scope has changed from the instrument’s stated intent."},"complexity_factors":["Narrow applicability limited to aircraft serial numbers 1–119 (reduces scope complexity)","Mandates following an external technical document (Boeing Canada Service Bulletin No. 8-57-10), requiring operators to obtain and apply technical instructions","Dual compliance deadline (within 500 flight hours after a trigger date OR by a fixed calendar date) which requires scheduling and tracking","Technical nature of the corrective action (fatigue-related strap installation), requiring qualified maintenance capability","Cross-reference to a foreign regulator’s AD (Transport Canada AD CF-89-02) which may require checking multiple documents"],"plain_english_summary":"What this directive does (mechanically)\n\n- This is an Airworthiness Directive (AD) that requires operators of certain Bombardier (Boeing Canada/De Havilland) DHC-8 aeroplanes to carry out a specific maintenance action. (Requirement)\n- The maintenance must be done in accordance with Boeing Canada DHC-8 Service Bulletin No. 8-57-10 dated 31 March 1989. (Requirement)\n- It applies only to aeroplanes with serial numbers 1 through 119. (Applicability)\n- The work must be completed within 500 hours time in service after 5 October 1989, or before 5 January 1990, whichever comes first. (Compliance)\n\nWho is affected\n\n- Owners and operators of DHC-8 aircraft with serial numbers 1–119 are required to perform the specified action. (Applicability, Requirement)\n\nWhy the rule was issued (stated purpose)\n\n- The AD cites fatigue failures on the subject straps caused by incorrect installation and directs corrective action as described in the manufacturer’s service bulletin. (Background, Requirement)\n\nHow this changes behaviour and who pays\n\n- Operators must schedule and perform the maintenance procedures defined in the referenced service bulletin; the AD does not state who pays, so the practical burden (labour, parts, aircraft downtime) falls on the aircraft owner/operator who must comply. (Requirement, Compliance)\n\nCompliance burden, timing and operational effects\n\n- The directive creates a firm compliance window: either within a specified flight-hours limit after a trigger date, or by an absolute calendar date, whichever occurs first. Operators must plan maintenance slots and may incur downtime or need to adjust operational schedules. (Compliance)\n- The action is technical and requires following the external service bulletin, so compliance requires access to that technical document and appropriately qualified maintenance personnel. (Requirement)\n\nRegulatory design, discretion and cross‑references\n\n- The AD prescribes a specific external technical document to be followed, leaving little discretion about how to comply beyond doing what the service bulletin requires. (Requirement)\n- The AD notes a related Transport Canada AD (CF-89-02), indicating cross-reference to an overseas regulator’s action. (Note)\n\nTrade-offs, risks and implementation considerations\n\n- The stated safety benefit is reduced risk of strap fatigue failure by correcting incorrect installation. (Background)\n- The likely trade-offs are direct maintenance costs and aircraft downtime for the operators of the affected serial numbers. (Requirement, Compliance)\n- Because the applicability is narrowly defined (serials 1–119), the cost and operational impact are concentrated on those operators. (Applicability)\n- Implementation risk is primarily operational (scheduling, ensuring technicians follow the service bulletin) rather than regulatory discretion, since the AD prescribes the remedial document. (Requirement)\n\nSource references within the instrument: Applicability; Requirement (Boeing Canada DHC-8 Service Bulletin No. 8-57-10 dated 31 March 1989); Compliance; Background; Note (Transport Canada AD CF-89-02)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive targeting a specific mechanical defect in a defined aircraft population. It has not expanded beyond its original purpose of mandating a one-time inspection/repair."},"complexity_factors":["Very short document (under 200 words)","Only 4 operative provisions: applicability, requirement, note, and compliance","Single cross-reference to an external technical document (Service Bulletin 8-57-10)","No defined terms section — all language is technical aviation terminology but used in standard industry sense","Simple temporal compliance condition ('whichever occurs first') with only two variables","No nested exceptions, conditional logic, or interpretive provisions"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific Bombardier DHC-8 aircraft (serial numbers 1 through 119) to inspect and fix a safety problem with **Flap Track No. 5 fail-safe straps**. These are structural components that help secure the aircraft's flaps (the movable surfaces on the wings that help with takeoff and landing).\n\n**The problem:** Some of these straps have developed **fatigue cracks** (tiny cracks caused by repeated stress) because they were installed incorrectly. This could lead to structural failure.\n\n**What must be done:** Aircraft operators must follow the repair instructions in **Boeing Canada Service Bulletin 8-57-10** (dated 31 March 1989). This is a technical manual that tells mechanics exactly how to inspect and fix the straps.\n\n**Who it affects:** Anyone operating DHC-8 aircraft with serial numbers 1–119 — mainly regional airlines and charter operators flying these turboprop planes.\n\n**When it had to be done:** By the earlier of either:\n- 500 flight hours after 5 October 1989, **or**\n- 5 January 1990\n\n**Why it matters:** Fatigue failures in flight control structures can be catastrophic. This AD prevents potential accidents by forcing a one-time safety fix before the straps could fail in service.\n\n**Note:** This references a Canadian safety order (Transport Canada AD CF-89-02), showing how aviation safety regulators share information across borders."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-9-flap-track-no-5-fail-safe-straps","history":"/api/acts/ad-dhc-8-9-flap-track-no-5-fail-safe-straps/history","analysis":"/api/acts/ad-dhc-8-9-flap-track-no-5-fail-safe-straps/analysis","conflicts":"/api/acts/ad-dhc-8-9-flap-track-no-5-fail-safe-straps/conflicts","importantCases":"/api/acts/ad-dhc-8-9-flap-track-no-5-fail-safe-straps/important-cases","documents":"/api/acts/ad-dhc-8-9-flap-track-no-5-fail-safe-straps/documents"}}