{"id":"F2009L03771","name":"AD/AT 800/9 Amdt 4 - Engine Mount","slug":"ad-at-800-9-amdt-4-engine-mount","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":141660,"registerId":"commonwealth-F2009L03771-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Airtractor 800 Series Aeroplanes","sectionType":"division","heading":"Airtractor 800 Series Aeroplanes","content":"### Airtractor 800 Series Aeroplanes\n\n| AD/AT 800/9 Amdt 4 | Engine Mount | 11/2009 |\n| ------------------ | ------------ | ------- |\n\n| Applicability: | Model AT-802 and AT-802A aircraft, serial numbers 0001 through 0227. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. For engine mounts without gussets installed, inspect the engine mount in accordance with Snow Engineering Co. SL No. 253 Revision C, dated17 April 2008:a. For aircraft with less than 5,000 hours time in service; at the initial and repetitive times specified in the Compliance section.b. For aircraft with 5,000 hours time in service or more; at the initial and repetitive times specified in the Compliance section.2. For engine mounts with gussets installed, inspect the engine mount in accordance with Snow Engineering Co. SL No. 253 Revision C, dated17 April 2008:a. For aircraft with less than 5,000 hours time in service; at the initial and repetitive times specified in the Compliance section.b. For aircraft with 5,000 hours time in service or more; at the initial and repetitive times specified in the Compliance section.Note: FAA AD 2009-11-05 Amdt 39-15915 refers. |\n| Compliance: | 1. a. Initially, upon accumulating 1,300 hours time in service or within the next 100 hours time in service after 30 August 2007, whichever occurs later. Repetitively thereafter at intervals not to exceed 300 hours time in service.1. b. Initially, upon accumulating 5,000 hours time in service or within the next10 hours time in service after 30 July 2009, or within the next 100 hours time in service from the last inspection performed, whichever occurs later. Repetitively thereafter at intervals not to exceed 100 hours time in service.2. a. Initially, upon accumulating 1,300 hours time in service or within the next 100 hours time in service after 30 July 2009, whichever occurs later. Repetitively thereafter at intervals not to exceed 300 hours time in service. |\n\n| | 2. b. Initially, upon accumulating 5,000 hours time in service or within the next10 hours time in service after 30 July 2009, or within the next 100 hours time in service from the last inspection performed, whichever occurs later. Repetitively thereafter at intervals not to exceed 100 hours time in service.The compliance times remain unchanged by this issue of the Directive. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 22 October 2009. |\n| Background: | The FAA received reports of cracked engine mounts. Such cracking, unless detected and corrected, could result in failure of the engine mount and possible separation of the engine from the aircraft.Amendment 1 was prompted by reports received by the FAA of two Model AT-802A aircraft with cracked engine mounts below the initial compliance time. The FAA determined that the initial inspection is required when the aircraft reaches a total of 1,300 hours time in service.Amendment 2 retained the inspection actions of FAA AD 2007-13-17 and required incorporation of engine mount gussets as a mandatory terminating action for the repetitive inspection requirement.Amendment 3 was prompted by a report of a Model AT-602 aircraft with a crack completely through the gusset that was installed as required in FAA AD 2008-10-12. Consequently, this Directive requires repetitive inspections of engine mounts of all previously affected aircraft with or without gussets installed.Amendment 4 is issued to correct minor typographical errors in Compliance section paragraphs 1.b. and 2.b. There is no change to the technical requirements. |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n4 September 2009","sortOrder":0},{"sectionNumber":"AD/AT 800/9 Amdt 4","sectionType":"part","heading":"AD/AT 800/9 Amdt 4","content":"## AD/AT 800/9 Amdt 4","sortOrder":1},{"sectionNumber":"Engine Mount","sectionType":"part","heading":"Engine Mount","content":"## Engine Mount","sortOrder":2},{"sectionNumber":"11/2009","sectionType":"part","heading":"11/2009","content":"## 11/2009","sortOrder":3}],"analysis":{"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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Amendment 4 makes typographical corrections to Compliance paragraph 1.b and 2.b only and explicitly states there is no change to the technical requirements; compliance times remain unchanged (Background). Earlier amendments had altered inspection timing and gusset requirements, but this amendment does not change scope."},"complexity_factors":["Applicability limited to specific models and a serial-number range (Model AT-802 and AT-802A, s/n 0001–0227) — operators must check eligibility.","Inspection procedure is external: requires following Snow Engineering Co. SL No. 253 Revision C (Requirement).","Multiple timing branches: initial inspections triggered at either ~1,300 hours or at a 5,000-hour threshold, with differing repetitive intervals (300 h vs 100 h) depending on hours and gusset status (Compliance paragraphs 1.a, 1.b, 2.a, 2.b).","Different treatment for mounts with and without gussets; past amendments made gusset installation a terminating action but current text requires repetitive inspections in both cases (Background).","Cross-reference to FAA AD 2009-11-05 and prior FAA ADs increases traceability and administrative steps (Requirement/Note; Background).","Amendment history and corrected typos (Amendment 4) create minor administrative/record-keeping complexity without altering technical obligations (Background).","Operational compliance burden: recurring inspections require tracking hours-in-service, scheduling downtime, and funding inspections/repairs (Compliance)."],"plain_english_summary":"This directive requires owners/operators of Airtractor AT-802 and AT-802A aircraft (serial numbers 0001–0227) to inspect engine mounts using Snow Engineering SL No. 253 Revision C. Inspection timing depends on whether gussets are fitted and on total hours in service, with specified initial inspections (1,300 h and 5,000 h thresholds) and repeat intervals (300 h or 100 h). Operators must schedule, perform and pay for inspections and any repairs. Amendment 4 corrects typographical errors only and does not change the technical inspection requirements."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is Amendment 4 of an existing Airworthiness Directive. The amendment explicitly states it only corrects 'minor typographical errors' in paragraphs 1.b. and 2.b. of the Compliance section, with no change to technical requirements. The scope remains limited to engine mount inspections for the specified Air Tractor aircraft models."},"complexity_factors":["Multiple nested conditions based on two variables: presence of gussets (yes/no) and flight hours (under/over 5,000)","Complex compliance timing with multiple 'whichever occurs later' triggers","Cross-reference to external technical document (Snow Engineering SL No. 253 Rev C) and US FAA AD 2009-11-05","Four amendment history references creating contextual dependency","Repetitive inspection intervals create ongoing compliance obligations"],"plain_english_summary":"This AD mandates mandatory inspections of engine mounts on Air Tractor AT-802/AT-802A (S/N 0001–0227) to detect cracks that could allow in-flight engine separation. Inspection timing and frequency depend on airframe hours and whether reinforcing gussets are fitted — lower-hour aircraft start inspections later and less often, high-hour aircraft require earlier and more frequent checks. Amendment 4 only corrects typos; requirements are unchanged."}},"importantCases":[],"_links":{"self":"/api/acts/ad-at-800-9-amdt-4-engine-mount","history":"/api/acts/ad-at-800-9-amdt-4-engine-mount/history","analysis":"/api/acts/ad-at-800-9-amdt-4-engine-mount/analysis","conflicts":"/api/acts/ad-at-800-9-amdt-4-engine-mount/conflicts","importantCases":"/api/acts/ad-at-800-9-amdt-4-engine-mount/important-cases","documents":"/api/acts/ad-at-800-9-amdt-4-engine-mount/documents"}}