{"id":"F2006B02540","name":"AD/AT 800/5 Amdt 1 - Aft Fuselage Structure Upper Longeron","slug":"ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41796,"registerId":"commonwealth-F2006B02540-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AT 800/5 Amdt 1 - Aft Fuselage Structure Upper Longeron","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\n![](image.001.png)  \n\nAirtractor 800 Series Aeroplanes\n\nAD/AT 800/5\n\nAmdt 1\n\n  \nAft Fuselage Structure Upper Longeron 10/2004\n\nApplicability: Model AT 802 and AT-802A aircraft, serial numbers 0001 through 0139. Requirement: 1. For Model AT-802 and AT-802A aircraft, serial numbers 0001 through 0004 and\n\n0012 through 0118:\n\nInspect the upper longeron on the left hand side of the fuselage frame, just forward of the vertical fin front spar attachment, for cracks in accordance with Snow Engineering Co. Service Letter (SL) No. 217A, dated 10 November 2003, as specified in SL No. 195, re-issued 10 November 2003.\n\n    2. For Model AT-802 and AT-802A aircraft, serial numbers 0005 through 0011:\n\nInspect the upper longeron on the left hand side of the fuselage frame, just forward of the vertical fin front spar attachment, for cracks in accordance with SL No. 217A, dated 10 November 2003, as specified in SL No. 195, re-issued 10 November 2003.\n\n    3. For Model AT-802 and AT-802A aircraft, serial numbers 0119 through 0139:\n\nInspect the upper longeron on the left hand side of the fuselage frame, just forward of the vertical fin front spar attachment, for cracks in accordance with SL No. 217A, dated 10 November 2003, as specified in SL No. 195, re-issued 10 November 2003.\n\nNote: FAA AD 2004-15-15 Amdt 39-13749 refers.\n\nCompliance: 1. Initially inspect upon the accumulation of 250 total hours time in service or within the next 100 hours time in service after the last inspection required by the original issue of this Directive, whichever occurs later. Inspect thereafter at intervals not to exceed 100 hours time in service, until the upper longeron is replaced and modified in accordance with SL No. 217B, revised 10 November 2003.\n\nAirtractor 800 Series Aeroplanes\n\nAD/AT 800/5 Amdt 1 (continued)\n\n    2. Initially inspect upon the accumulation of 900 total hours time in service or within the next 100 hours time in service after the last inspection required by the original issue of this Directive, whichever occurs later. Inspect thereafter at intervals not to exceed 100 hours time in service, until the upper longeron is replaced and modified in accordance with SL No. 217B, revised 10 November 2003.\n\n    3. Initially inspect upon the accumulation of 1,750 total hours time in service or within the next 100 hours time in service after the last inspection required by the original issue of this Directive, whichever occurs later. Inspect thereafter at intervals not to exceed 100 hours time in service, until the upper longeron is replaced and modified in accordance with SL No. 217B, revised 10 November 2003.\n\nThis Airworthiness Directive becomes effective on 30 September 2004.\n\nBackground: The FAA received reports of three occurrences of cracks found on the left hand upper longeron and upper diagonal support tubes where they intersect on the left side of the fuselage frame just forward of the vertical fin front spar attachment point, on Model AT-602 aircraft. The cracks were found by the pilot and/or ground crew when they noticed excessive movement of the empennage due to the loss of torsional rigidity.\n\nAmendment 1 is issued in response to a new FAA AD, which changes the compliance times, and incorporates new and revised manufacturer service information that contains a terminating action for the repetitive inspection requirement.\n\n![](image.002.png)  \n\nDavid Villiers\n\nDelegate of the Civil Aviation Safety Authority 20 August 2004\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 8 September 2004.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment alters the original AD by changing the compliance times for initial inspections and by incorporating revised manufacturer service information that provides a terminating action (replacement/modification per SL No. 217B) for the repetitive inspection requirement. In other words, the scope shifted from only mandating repeated inspections to specifying a permanent repair/modification that ends the inspection cycle (Amendment 1; Background)."},"complexity_factors":["Three serial‑number cohorts with different initial inspection hour triggers (250, 900, 1,750)","Uniform repetitive inspection interval (every 100 hours) until terminating action","Cross‑reference to multiple manufacturer service letters (SL No. 217A, SL No. 217B, SL No. 195)","Reference to an FAA AD for related context","Conditional timing language: \"upon accumulation of X total hours or within the next 100 hours after the last inspection required by the original issue, whichever occurs later\"","Termination of inspections only upon completion of a specified modification (SL No. 217B)"],"plain_english_summary":"**What this instrument does (mechanics)**\n\n- This Airworthiness Directive (AD) orders owners/operators of certain Airtractor 800-series aeroplanes to inspect a specific structural part of the fuselage — the left‑side upper longeron just forward of the vertical fin front spar attachment — for cracks. (Applicability; Requirement)\n\n- It divides affected aeroplanes into three serial‑number groups and sets different initial inspection trigger times for each group: 250, 900 and 1,750 total hours time‑in‑service respectively, or within the next 100 hours after the last inspection required by the original AD, whichever is later. After that initial check, inspections must be repeated at intervals not exceeding 100 hours time‑in‑service until the longeron has been replaced and modified according to the manufacturer’s service information (Service Letter SL No. 217B, revised 10 November 2003). (Applicability; Compliance)\n\n- The AD refers operators to Snow Engineering Company Service Letters SL No. 217A and SL No. 195 (re‑issued 10 November 2003) for the inspection procedure and to SL No. 217B for the terminating modification. It also notes an equivalent FAA AD. (Requirement; Background)\n\n**Who is affected**\n\n- Owners and operators of Airtractor Model AT‑802 and AT‑802A aircraft, serial numbers 0001 through 0139. The AD separates that range into three cohorts (0001–0004 & 0012–0118; 0005–0011; and 0119–0139) for timing of the initial inspection. (Applicability)\n\n- Maintenance organisations and mechanics who perform the inspection and the later replacement/modification required to terminate repetitive inspections. (Requirement; Compliance)\n\n**Why it matters (stated safety rationale)**\n\n- The FAA reported cracks in the same area on related Airtractor models. The cracks can reduce torsional rigidity of the empennage, causing excessive movement of the tail surfaces, which presents an in‑flight structural safety risk. The AD’s inspections seek to detect cracks early; the replacement/modification is the specified terminating action to remove the need for repetitive inspections. (Background; Requirement)\n\n**Who pays, who decides, and how behaviour changes**\n\n- Operators pay for the inspections, labour, any parts, and downtime. If a terminating modification is chosen, operators also pay for the replacement/repair specified in SL No. 217B. (Requirement; Compliance)\n\n- The Civil Aviation Safety Authority delegate issued the AD; operators must follow the inspection intervals and the referenced service letters. Maintenance providers decide how to schedule and carry out the inspections and modifications under the service letter instructions. (AD text; Requirement)\n\n- Behavioural change: operators must schedule periodic inspections every 100 hours (after the initial trigger) and must either continue inspections indefinitely or perform the replacement/modification that ends the inspection cycle. (Compliance)\n\n**Costs, incentives, trade‑offs and practical effects**\n\n- Direct costs: inspection labour, possible repair or replacement costs if cracks are found, and operational downtime while inspections or modifications are performed.\n\n- Incentives: operators have a clear incentive to perform the terminating modification (SL No. 217B) to stop the recurring inspection burden and reduce ongoing downtime and administrative cost.\n\n- Concentrated benefits and costs: the primary beneficiary is improved structural safety for affected aircraft; the concentrated cost falls on aircraft owners/operators in the serial number range and on the maintenance organisations that supply the work. The manufacturer and approved repair providers may receive concentrated revenue from parts and modification work.\n\n- Implementation risk and detection limits: the AD relies on visual/other inspection methods described in the service letters. If inspections fail to detect small or internal cracks, the safety objective may be compromised until the terminating modification is completed. The AD’s effectiveness therefore depends on proper compliance with the manufacturer’s inspection procedures. (Requirement; Background)\n\n- Effects on private choice and competition: the AD imposes a compliance standard that all affected operators must meet, reducing operational flexibility (inspection scheduling and potential temporary grounding). Independent maintenance businesses can perform the work under the service letters, so the measure does not restrict which approved maintenance provider may be engaged, but it does create demand for specialist parts/skills.\n\n**Source claim and testing against implementation costs**\n\n- The AD claims the inspections and modification respond to observed cracks on related models and that the revised compliance times plus SL No. 217B provide a terminating action. Testing that claim against costs: the terminating action likely reduces long‑term inspection costs but requires a near‑term capital and downtime outlay; the AD therefore shifts costs from recurring (inspections) to a one‑time modification expense for operators who choose the terminating action. (Background; Compliance; Requirement)"},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose — addressing structural cracks in the aft fuselage upper longeron of specific Air Tractor aircraft. The changes adjust compliance times and add a terminating action, but do not expand the directive to new aircraft models, new structural areas, or unrelated safety issues."},"complexity_factors":["Three distinct serial number ranges with different compliance thresholds (250, 900, and 1,750 hours)","Cross-reference to external manufacturer documents (Snow Engineering Service Letters 195, 217A, and 217B) which are not reproduced in the text","Conditional timing logic: 'whichever occurs later' clauses for initial inspections","Repetitive inspection requirement until terminating action completed","Reference to corresponding FAA AD (2004-15-15) without full incorporation"],"plain_english_summary":"This AD requires owners/operators of Air Tractor AT-802 and AT-802A aeroplanes (S/N 0001–0139) to inspect the left rear-fuselage upper longeron for cracks because failure could loosen the empennage and risk loss of control. Initial inspection timing varies by serial-number group, with repeats every 100 flight hours until the part is replaced and modified per the manufacturer’s Service Letter 217B. This amendment shortens some inspection deadlines and adds that terminating modification."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron","history":"/api/acts/ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron/history","analysis":"/api/acts/ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron/analysis","conflicts":"/api/acts/ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron/conflicts","importantCases":"/api/acts/ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron/important-cases","documents":"/api/acts/ad-at-800-5-amdt-1-aft-fuselage-structure-upper-longeron/documents"}}