{"id":"F2005L02381","name":"AD/FSM/29 Amdt 4 - Precision Airmotive Corporation Carburettors","slug":"ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":36792,"registerId":"commonwealth-F2005L02381-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Fuel Supply and Metering Equipment","sectionType":"division","heading":"Fuel Supply and Metering Equipment","content":"### Fuel Supply and Metering Equipment\n\n| AD/FSM/29 Amdt 4 | Precision Airmotive Corporation Carburettors | 10/2005 |\n| ---------------- | -------------------------------------------- | ------- |\n\n| Applicability: | Precision Airmotive Corporation (PAC, formerly Facet Aerospace Products Corporation and Marvel-Schebler Corporation) Model MA-3, MA-3A, MA-3PA, MA-3SPA, MA-4SPA carburettors installed on but not limited to Textron Lycoming O-235, O-290, and O-320 series engines, and Teledyne Continental Motors (TCM) A-65, A-75, C-75, C-85, C-90, C-115, C-125, C-145, O-200, and O-300 series engines. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | Model MA-3A, MA-3PA, MA-3SPA, and MA4-SPA carburettors:1. Inspect the carburettor to determine if a two-piece venturi is installed. If a two-piece venturi is installed, inspect the carburettor to determine if the primary venturi is loose or missing.2. If a two-piece venturi is installed and the primary venturi is found loose or missing, repair the carburettor by installing a serviceable two-piece venturi or by installing a one-piece venturi as per provisions of Precision Airmotive Service Bulletin (SB) No. MSA-2, Revision 1, 2, 3 or later FAA approved revision.Note 1: Carburettors that have the letter \"V\" stamped or etched on the lower portion of the data plate, or that have a black, yellow, or blue data plate showing the Precision Airmotive Corporation (PAC) name and logo, or that have a black Facet Aerospace Products data plate with a serial number beginning with 750, are already equipped with a one-piece venturi and no further action is necessary provided the engine does not subsequently run rough or experience power loss.3. IF the carburettor is fitted with a one-piece venturi AND the engine runs rough or experiences power loss AND providing the rough running engine or power loss can be traced to the carburettor venturi or fuel nozzle THEN accomplish either of the following:3A Install a carburettor containing a two-piece venturi and resume the inspections as per requirement 1 and 2 of this AD; OR |\n\n| | 3B Modify the carburettor in accordance with paragraphs 3B-(a), 3B-(b), or 3B-(c) of this Directive, as applicable:(a) For PAC Model MA-3SPA series carburettors with part numbers (P/N) 10-4894 or 10-4115-1, installed on TCM Model O-200A series engines modified by installing a one-piece venturi, install a new fuel nozzle in accordance with PAC SB MSA-7, dated 30 September 1994.(b) For PAC Model MA-3SPA series carburettors with P/Ns 10-4895, 10-4439, or 10-3237, installed on TCM Model O-300 or C-145 series engines modified by installing a one-piece venturi, install a new fuel nozzle in accordance with PAC SB No. MSA-8, dated 10 July 1995.(c) For PAC Model MA-3SPA series carburettors with P/Ns 10-4240, 10-4252, 10-4252-1, or 10-4457, installed on TCM Model C-75, C-85, or C-90 series engines modified by installing a one-piece venturi, install a new fuel nozzle in accordance with PAC SB No. MSA-9, dated 10 October 1995.Note 2: Model MA-3A, MA-3PA, and MA4-SPA carburettors already utilize the type of nozzles referred to, in the modification requirement 3B hence no further mandatory modifications are available at present.Note 3: Installing a one-piece venturi constitutes terminating action for the repetitive inspection as per requirement 1 of this AD.Model MA-3 series carburettors:4. Inspect the carburettor to determine if the primary venturi is loose or missing.5. If the primary venturi is found loose or missing, repair the carburettor by installing a serviceable two-piece venturi, or replace the entire carburettor with a serviceable carburettor.Note 4: FAA AD 98-01-06 Amendment 39-10270 refers. |\n| ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | 1. Unless accomplished earlier, within 50 flight hours or 30 days from the effective date of this Directive, whichever comes first and repetitively thereafter, at each annual or 100-hourly inspection, whichever comes first.2. Before further flight, following inspection per requirement 1 of this Directive.3. Before further flight.Note 5: If necessary, an entry into the Maintenance Release may be made to facilitate compliance to the Requirement 3. |\n\n| | 4. Unless accomplished earlier, within 50 flight hours or 30 days from the effective date of this Directive, whichever comes first and repetitively thereafter, at each annual or 100-hourly inspection, whichever comes first.5. Before further flight, following inspection per requirement 4 of this Directive. |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 29 September 2005. |\n| Background: | Disruption of fuel flow to the engine may result in the failure to attain rated power, power loss in flight, and forced landings. This AD addresses the identified unsafe condition associated with the power loss in flight.The current Amendment provides further explanation on the AD Requirements.Amendment 3 of this Directive clarified the issue of fuel nozzle modifications for the Model MA-3A, MA-3PA, and MA4-SPA carburettors and became effective on 14 April 2005.Amendment 2 of this AD became effective on 17 February 2005 and reflected requirements of FAA AD 98-01-06.Amendment 1 of this AD became effective on 1 January 1998 and made reference to now superseded FAA AD 93-18-03.The original issue of this AD became effective on 6 January 1994. |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n15 August 2005","sortOrder":0},{"sectionNumber":"AD/FSM/29 Amdt 4","sectionType":"part","heading":"AD/FSM/29 Amdt 4","content":"## AD/FSM/29 Amdt 4","sortOrder":1},{"sectionNumber":"Precision Airmotive Corporation Carburet","sectionType":"part","heading":"Precision Airmotive Corporation Carburettors","content":"## Precision Airmotive Corporation Carburettors","sortOrder":2},{"sectionNumber":"10/2005","sectionType":"part","heading":"10/2005","content":"## 10/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"The directive has evolved since the original 1994 issue. Later amendments aligned the AD with FAA AD 98‑01‑06 (Amendment 2), clarified fuel‑nozzle modification requirements for specific P/N/engine combinations (Amendment 3), and the current amendment provides additional explanation of requirements. These changes refine corrective options (including a defined terminating action: installing a one‑piece venturi), specify different service‑bulletin fixes for particular carburettor P/Ns, and clarify compliance mechanics, while continuing to target the same PAC MA‑series carburettors (Background; Requirements; Notes)."},"complexity_factors":["Multiple conditional branches: different requirements depending on whether a two‑piece or one‑piece venturi is installed and whether engine roughness/power loss is traceable to the venturi (Requirements 1–5, 3A–3B).","Numerous affected carburettor models and many engine series across PAC, Lycoming and Teledyne Continental (Applicability table).","Specific part‑numbered instructions and different service bulletin references (PAC SB MSA‑2, MSA‑7, MSA‑8, MSA‑9) tied to particular P/Ns and engine models (Requirement 3B(a)–(c)).","Repetitive inspection regime with short compliance windows (within 50 flight hours or 30 days, and at each annual/100‑hour inspection) creating ongoing maintenance burden (Compliance).","A terminating action exists (installing a one‑piece venturi) that stops the repetitive inspection requirement, introducing a choice between recurring inspections and a one‑off modification (Note 3).","Exceptions and identification criteria based on data‑plate markings and serial numbers (Note 1), requiring record checks and possible physical verification.","Cross‑references to prior FAA ADs and earlier amendments, and evolution across amendments that affect interpretive clarity (Background).","Operational urgency: some corrective actions must be done before further flight, potentially grounding aircraft until maintenance is completed (Compliance requirements 'Before further flight').","Administrative requirement allowing Maintenance Release entries to facilitate compliance (Note 5), adding procedural discretion for maintainers/operators."],"plain_english_summary":"This directive requires owners/operators of aircraft fitted with specified Precision Airmotive (PAC) MA-series carburettors to inspect for two-piece venturis and, if the primary venturi is loose or missing, to repair by installing a serviceable two-piece venturi, replace the carburettor, or install a one-piece venturi. For particular part numbers and engine types the AD mandates specific fuel-nozzle modifications per Precision Airmotive service bulletins. Compliance includes short-term and repetitive inspection deadlines and before‑flight corrective actions; the obligations fall on operators and maintenance providers."},"kimi_summary":{"content_quality":"ok","complexity_score":7,"scope_assessment":{"changed":true,"description":"Originally issued in 1994 as a straightforward safety directive addressing loose venturis in specific carburettors, this AD has expanded significantly through four amendments. Amendment 2 incorporated FAA requirements, Amendment 3 added fuel nozzle modifications, and Amendment 4 introduced complex conditional pathways for aircraft already modified with one-piece venturis that still experience problems. The original scope was 'inspect and fix loose venturis'; it now encompasses multiple repair pathways, part-number-specific modifications, and ongoing airworthiness management for aircraft with both two-piece AND one-piece venturis."},"complexity_factors":["Multiple overlapping model categories with different requirements (MA-3 vs MA-3A/PA/SPA/MA-4SPA)","Nested conditional logic: Requirement 3 triggers only if three conditions are met simultaneously (one-piece venturi installed AND rough running/power loss AND traceable to carburettor)","Three alternative modification paths under Requirement 3B, each tied to specific part numbers and engine models","Cross-references to four different manufacturer service bulletins (MSA-2, MSA-7, MSA-8, MSA-9) and one FAA AD (98-01-06)","Exception clauses (Notes 1-5) that modify or exempt certain requirements based on physical markings (stamped 'V', data plate colors, serial number prefixes)","Different compliance timeframes for different requirements (50 hours/30 days vs before further flight)","Terminating action concept (installing one-piece venturi ends repetitive inspection obligation for some but not all scenarios)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of aircraft with certain Lycoming and Continental engines fitted with Precision Airmotive MA-3/MA-4 series carburettors to inspect for loose or missing two-piece venturis that can detach and cause in-flight power loss. \n\nInspections are due within 50 flight hours or 30 days and at each annual/100‑hour check; detected faults must be repaired before flight. Replacing the two-piece venturi with a one-piece unit eliminates the recurring inspection 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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors","history":"/api/acts/ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors/history","analysis":"/api/acts/ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors/analysis","conflicts":"/api/acts/ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors/conflicts","importantCases":"/api/acts/ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors/important-cases","documents":"/api/acts/ad-fsm-29-amdt-4-precision-airmotive-corporation-carburettors/documents"}}