{"id":"F2006B02538","name":"AD/AT 800/2 Amdt 4 - Airframe Life Limits","slug":"ad-at-800-2-amdt-4-airframe-life-limits","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41794,"registerId":"commonwealth-F2006B02538-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AT 800/2 Amdt 4 - Airframe Life Limits","content":"![](image.001.png)\n\n![](image.002.png) \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AT 800/2 Amdt 3 and issues the following AD under subregulation 39.1 (1) of CAR 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 800/2\n\nAmdt 4\n\n \n\nAirframe Life Limits 8/2001 DM\n\nApplicability: All models AT-802 and AT-802A aeroplanes.\n\nRequirement: Retire from service the airframe components listed in the Retirement Schedule below.\n\n```html\n

RETIREMENT SCHEDULE

Component

Part No.

Aircraft S/N

Retirement Life (Flight Hours)

Wing Attach Block on Lower Cap

20602-1

All

6500 (See Note 1)

Wing Attach Block on Lower Cap

20602-2

All

6500 (See Note 1)

Plate Assembly – Fin Front Spar Attach

30511-1

0001 thru 0041

4000 (See Note 2)

0042 and up

20000

Spar Assembly – Fin Rear

30505-1

0001 thru 0041

4000 (See Note 2)

0042 and up

20000

Spring - Main Landing Gear Leg (including the forward and aft main gear clamp block bolts and the inboard main gear large bolt).

40091-2

All

1000 hours or 2500 landings, whichever occurs first.

Spring - Main Landing Gear Leg (including the forward and aft main gear clamp block bolts and the inboard main gear large bolt).

40091-3

All

3000 hours or 8000 landings, whichever occurs first.

Spring – Tail Landing Gear

40092-5

All

2500 hours or 7000 landings, whichever occurs first.

Spring – Tail Landing Gear

40092-6

All

3000 hours or 8000 landings, whichever occurs first.

\n```\n\nWhere the total number of landings during a period of service has not been recorded, three landings per one hour time in service must be assumed.\n\nCompliance: Retire prior to exceeding the applicable time in service listed in the Retirement Schedule.\n\nNote 1: Splice block lives may be extended to 10000 hours on incorporation of Snow SL # 185 revised issue dated 9/3/99.\n\nAirtractor 800 Series Aeroplanes\n\nAD/AT 800/2 Amdt 4 (Continued)\n\nNote 2: Fin spar and attach plate lives may be extended to 20000 hours on incorporation of Snow SL # 187.\n\nNote 3: The Type Certificate Data Sheet states that the lives are listed in the Maintenance Manual; however they are in fact listed in the Owners Manual.\n\nThis Amendment becomes effective on 27 June 2001.\n\nBackground: Airframe component life limitations determined by the manufacturer have been published in the Airworthiness Limitations section of the Owners Manual.\n\nAmendment 1 included new and revised lives for some landing gear components. Amendment 2 implemented extended lives for wing and fin spar components and expressed tail gear spring lives in landings as well as hours, as for the MLG spring leg lives. This Amendment follows further information received from the manufacturer, and clarifies aircraft serial number applicability for the fin component lives. A part number error has also been corrected.\n\nAmendment 4 is issued to delete the wing spar cap retirement lives from the retirement schedule; as the retirement lives are now contained in AD/AT 800/3.\n\nAmendment 3 of this Airworthiness Directive became effective on 10 August 2000\\. Amendment 2 of this Airworthiness Directive became effective on 13 July 2000.\n\nThe original issue of this Directive became applicable on 15 August 1996.\n\n![](image.003.png) \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 21 June 2001\n\n![](image.002.png) \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 June 2001.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"Yes. Amendment 4 alters the AD’s scope relative to prior issues by deleting the wing spar cap retirement lives from this directive (those lives are now in AD/AT 800/3), clarifying serial-number applicability for fin component lives, and correcting a part number error. It also preserves conditional life-extension paths via specific Snow service letters and changes how certain gear lives are expressed (hours and/or landings) (Background; Notes 1–3)."},"complexity_factors":["Multiple retirement metrics: some components retire by flight hours, others by landings, and many by “hours or landings, whichever occurs first” (Retirement Schedule).","Serial-number differentiation: fin plate and spar assemblies have different lives depending on aircraft S/N ranges (0001–0041 vs 0042 and up).","Conditional life extensions: splice block and fin spar/attach plate lives may be extended only on incorporation of Snow SL #185 and Snow SL #187 respectively (Notes 1 & 2).","Counting assumption for missing data: where total landings aren’t recorded, operators must assume three landings per hour (Requirement text).","Cross-reference to other ADs: wing spar cap lives were deleted here because they are now contained in AD/AT 800/3 (Background), requiring operators to consult multiple instruments.","Amendment history and corrections: the AD revokes the previous amendment, corrects a part number error and clarifies applicability (Background), increasing record‑checking burden.","Mixed component scope: the schedule covers a variety of hardware (spars, attach plates, spring legs and associated bolts) which affects inspection, part-tracking and maintenance planning.","Dual counting units for landing gear springs (hours and landings) with different thresholds (e.g. 1000 hours or 2500 landings vs 3000 hours or 8000 landings).","Mandatory pre-exceedance retirement: operators must remove parts before exceeding listed lives, imposing operational and logistical planning requirements (Compliance)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Airtractor AT-802 and AT-802A aeroplanes to remove specified airframe parts from service once they reach the flight-hour or landing limits in the Retirement Schedule. It also sets a rule for counting landings (assume three landings per flight hour if landings aren’t recorded) and allows certain life extensions only if specified Snow service letters are incorporated. The AD shifts wing spar cap lives to a different AD and clarifies serial-number applicability for some fin components."},"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":4,"scope_assessment":{"changed":true,"description":"The original directive (August 1996) appears to have covered wing spar caps. Amendment 4 explicitly removes wing spar cap retirement lives from this schedule, transferring them to a separate directive (AD/AT 800/3). This represents a narrowing of scope for this particular AD, but an expansion of the overall regulatory framework. The amendment also refined serial number applicability for fin components and corrected part number errors, suggesting iterative refinement of the regulatory scope based on manufacturer data and operational experience."},"complexity_factors":["Multiple part numbers with different life limits for the same component type (e.g., two different main landing gear springs with different limits)","Serial number-dependent applicability creating a split in retirement limits (aircraft 0001-0041 vs 0042+ for fin components)","Dual-metric compliance triggers (flight hours OR landings, whichever occurs first)","Assumption rule for missing data (3 landings per hour when records are incomplete)","Cross-references to external documents (Snow Service Letters #185 and #187 for life extensions)","Reference to a separate AD (AD/AT 800/3) for wing spar caps, indicating distributed regulatory coverage","Amendment history tracking (this is Amendment 4, with references to previous amendments and their changes)"],"plain_english_summary":"This CASA Airworthiness Directive mandates retirement limits for critical structural and landing-gear parts on Air Tractor AT-802/AT-802A aeroplanes, requiring operators and maintenance engineers to remove and replace components once they reach specified hours or landings. It affects owners, maintainers and indirectly pilots, including rules for counting landings (assume 3 per flight hour) and limited life extensions via manufacturer service bulletins. The AD prevents metal-fatigue failures in demanding low-level, heavy-load operations, preserving safety and regulatory compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-800-2-amdt-4-airframe-life-limits","history":"/api/acts/ad-at-800-2-amdt-4-airframe-life-limits/history","analysis":"/api/acts/ad-at-800-2-amdt-4-airframe-life-limits/analysis","conflicts":"/api/acts/ad-at-800-2-amdt-4-airframe-life-limits/conflicts","importantCases":"/api/acts/ad-at-800-2-amdt-4-airframe-life-limits/important-cases","documents":"/api/acts/ad-at-800-2-amdt-4-airframe-life-limits/documents"}}