{"id":"F2008L02572","name":"AD/AT 600/8 - Overturn Skid Plate","slug":"ad-at-600-8-overturn-skid-plate","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74577,"registerId":"commonwealth-F2008L02572-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Airtractor 600 Series Aeroplanes","sectionType":"division","heading":"Airtractor 600 Series Aeroplanes","content":"### Airtractor 600 Series Aeroplanes\n\n| AD/AT 600/8 | Overturn Skid Plate | 8/2008 |\n| ----------- | ------------------- | ------ |\n\n| Applicability: | Air Tractor AT-602 with Serial Numbers -0337 through -1153. |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | If overturn skid plate kit part number (P/N) 11411-1-500 or an FAA-approved equivalent P/N is already installed, then install P/N 11411-1-501 modification kit.If there is no overturn skid plate installed, then install overturn skid plate kitP/N 11411-1-502 or an FAA approved equivalent part number.Note: FAA AD 2008-11-17 and Snow Engineering Service Letter #97, revised7 November 2007 refers. |\n| Compliance: | Within 180 days after the effective date of this AD. |\n| | This Airworthiness Directive becomes effective on 31 July 2008. |\n| Background: | The FAA received accident reports on Model AT-301 and AT-401 aircraft which indicate that the aircraft skids tail first during an overturn. As a result, the windshield and curved overturn tube act as a scoop, foreign material enters the cockpit if the canopy is damaged; and this foreign material then enters into the cabin area and possibly contributes to pilot deaths. The manufacturer installed an overturn skid plate which was intended to minimise the possibility of dirt or mud penetrating the cockpit during an overturn skid and causing pilot asphyxia or injury.There have subsequently been reports of the bolts that attach the forward end of the original design overturn skid plate breaking in an overturn accident. This allowed the skid plate to rotate around the rear attach point and the forward end of the plate to enter the cockpit area. This Airworthiness Directive is issued to ensure overturn skid plates are installed and, if already installed, prevent the front and rear connections of the overturn skid plate to the airframe breaking. |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n13 June 2008","sortOrder":0},{"sectionNumber":"AD/AT 600/8","sectionType":"part","heading":"AD/AT 600/8","content":"## AD/AT 600/8","sortOrder":1},{"sectionNumber":"Overturn Skid Plate","sectionType":"part","heading":"Overturn Skid Plate","content":"## Overturn Skid Plate","sortOrder":2},{"sectionNumber":"8/2008","sectionType":"part","heading":"8/2008","content":"## 8/2008","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":"This AD sticks to its original safety-focused purpose: to ensure an overturn skid plate is present and that its forward and rear attachments will not fail in an overturn. It does not expand the regulatory scope beyond that safety objective. The instrument applies to a specific model and serial number range and prescribes a narrowly defined corrective action (specified part numbers or FAA‑approved equivalents), consistent with the stated rationale and with the FAA AD and manufacturer service letter it cites."},"complexity_factors":["Short, single-topic directive (one aircraft model and defined serial‑number range).","Two conditional branches in the requirement: (a) upgrade if P/N 11411-1-500 is fitted; (b) install P/N 11411-1-502 if no plate is fitted.","References to external materials (FAA AD 2008-11-17 and manufacturer service letter) requiring cross-checking.","Allowance for FAA‑approved equivalent part numbers introduces conditional regulatory discretion.","Single fixed compliance period (180 days) — low temporal complexity.","No numerous defined terms or multi‑part exceptions; straightforward applicability and remedy."],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires owners/operators of Air Tractor AT-602 aeroplanes with serial numbers -0337 through -1153 to fit a specified overturn skid plate kit within 180 days. (Applicability; Requirement; Compliance)\n- If an older overturn skid plate with part number (P/N) 11411-1-500 or an FAA‑approved equivalent is already fitted, the owner/operator must install modification kit P/N 11411-1-501. (Requirement)\n- If no overturn skid plate is fitted, the owner/operator must install overturn skid plate kit P/N 11411-1-502 or an FAA‑approved equivalent. (Requirement)\n\n**Who this affects**\n\n- Aircraft owners and operators of Air Tractor AT-602 aeroplanes with serial numbers -0337 through -1153. (Applicability)\n- Maintenance organisations and parts suppliers who will supply and fit the specified kits or approved equivalents. (Requirement)\n\n**Why it matters (stated purpose and mechanical effect)**\n\n- The stated reason is to prevent a failure mode observed in overturn accidents where the forward attachments of the original skid plate break, allowing the plate to rotate and intrude into the cockpit and permitting foreign material to enter the cabin, which may contribute to serious injury or death. The instrument implements a mandatory retrofit or installation to ensure the skid plate is present and that its forward and rear attachments are strengthened or replaced. (Background; Requirement)\n\n**Practical consequences and implementation mechanics**\n\n- Who pays: aircraft owners/operators pay for parts, labour, and any downtime.\n- Who decides: the regulator’s delegate enforces the directive; the record refers to FAA AD 2008-11-17 and a manufacturer service letter as guidance for the corrective action and allows FAA‑approved equivalent part numbers (introducing some regulatory and manufacturer discretion). (Requirement; Background)\n- Timing: work must be completed within 180 days of the AD’s effective date. (Compliance)\n- Compliance burden: sourcing the specified kit or an FAA‑approved equivalent, scheduling maintenance, and aircraft out-of-service time while work is done.\n\n**Costs, incentives and trade-offs**\n\n- Concentrated costs fall on a defined group of owners/operators (those operating the specified serial-numbered AT-602s). The safety benefit accrues primarily to the same operators and their crews/passengers. (Applicability; Background)\n- The rule reduces operator choice about whether to accept the risk of operating without the retrofit; the allowed use of FAA‑approved equivalents maintains some flexibility in parts sourcing. (Requirement)\n- Potential supply-side effects: if many affected aircraft seek the same kit within 180 days, there is a risk of parts shortages or increased prices for parts and fitting services. That is an implementation risk, not stated as having occurred here. (Requirement; Compliance)\n- Administrative discretion: the instrument’s reference to FAA approval for equivalent parts means an external approval process determines acceptable alternatives; this creates a point of regulatory discretion. (Requirement)\n\n**Implementation risk, opportunity cost and likely operator responses**\n\n- Implementation risk includes parts availability and workshop capacity. Opportunity cost is aircraft downtime while the work is done.\n- Likely operator responses are to schedule the modification during planned maintenance or grounding, or to source FAA‑approved equivalent parts if original kits are unavailable or more expensive. (Requirement; Compliance)\n\n**Source claims vs. mechanical effect**\n\n- The instrument cites accident reports and prior field experience of bolt failures as the factual basis for the requirement. Mechanically, it mandates either upgrade of an existing skid plate (11411-1-500 → 11411-1-501) or installation of a specified plate (11411-1-502). The practical effect is to alter the aircraft structure at the skid plate forward and/or rear attachment points to reduce the chance that the skid plate will detach and intrude into the cockpit during an overturn. (Background; Requirement)\n\n**Reference notes**\n\n- Compliance window is 180 days after the effective date. (Compliance)\n- The AD references FAA AD 2008-11-17 and Snow Engineering Service Letter #97 (revised 7 Nov 2007) for related guidance. (Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a targeted safety directive addressing a specific mechanical defect in a specific aircraft model. The scope remains precisely limited to the overturn skid plate issue as originally identified."},"complexity_factors":["Very short document (approximately 250 words of substantive content)","Only 3 defined part numbers referenced","Simple conditional logic (two scenarios: plate installed vs. not installed)","No cross-references to other legislation or complex regulatory frameworks","Single compliance deadline with no exceptions or extensions mentioned","Narrow applicability (specific aircraft model and serial number range)"],"plain_english_summary":"This AD requires operators of Air Tractor AT-602 airplanes (S/N -0337 through -1153) to install or upgrade the overturn skid plate to a strengthened design so it cannot detach and intrude into the cockpit if the aircraft overturns. It addresses previous crash injuries from mud/objects entering the cockpit. Compliance is required within 180 days after July 31, 2008."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-600-8-overturn-skid-plate","history":"/api/acts/ad-at-600-8-overturn-skid-plate/history","analysis":"/api/acts/ad-at-600-8-overturn-skid-plate/analysis","conflicts":"/api/acts/ad-at-600-8-overturn-skid-plate/conflicts","importantCases":"/api/acts/ad-at-600-8-overturn-skid-plate/important-cases","documents":"/api/acts/ad-at-600-8-overturn-skid-plate/documents"}}