{"id":"F2011L02807","name":"AD/TFE 731/33 Amdt 1 - LPT Stage 1 Nozzle and Disks","slug":"ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":126202,"registerId":"commonwealth-F2011L02807-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AlliedSignal (Garrett/AiResearch) Turbin","sectionType":"division","heading":"AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series","content":"### AlliedSignal (Garrett/AiResearch) Turbine Engines - TFE731 Series\n\n| AD/TFE 731/33 Amdt 1 | LPT Stage 1 Nozzle and Disks | 26/2011 |\n| -------------------- | ---------------------------- | ------- |\n\n| Applicability: | Honeywell International Inc. (formerly AlliedSignal Inc. and Garrett Turbine Engine Co.) TFE731-2 and -2C series, and TFE731-3, -3A, -3AR, -3B, -3BR, and -3R series turbofan engines, with low pressure turbine (LPT) stage 1 discs, part numbers (P/Ns) 3072070-All, 3072351-All, 3073013-All, 3073113-All, 3073497- All, and3074103-All, (where All denotes all dash numbers), installed.Note 1: These engines are installed on, but not limited to, the following aeroplanes:Avions Marcel Dassault Falcon 10 and Mystere Falcon 50 series Learjet 31, 35, 36, and 55 series Lockheed-Georgia 1329-25 series Israel Aircraft Industries 1124 series and 1125 Westwind series Cessna Model 650, Citations III and VI Raytheon British Aerospace HS-125 series Sabreliner NA-265-65. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. Initial Inspection for TFE731-2 and -2C Series EnginesFor TFE731-2 and -2C series engines with Low Pressure Turbine (LPT) stage 1 disc, Part Number (P/N) 3072070-All, or 3073013-All, installed, do the following:(a) Measure throat dimensions, air flow and determine serviceability of the LPT stage 1 nozzle assembly using paragraphs 2.A. (3) through 2.A. (5) of Honeywell International Inc. Service Bulletin (SB) No.TFE731-72-3369RWK, Revision 6, dated 26 June 2002; and(b) If necessary, adjust the LPT stage 1 nozzle assembly using paragraph 2.B of Honeywell International Inc. SB No. TFE731-72- 3369RWK, Revision 6, or replace with a serviceable LPT stage 1 nozzle assembly.2. Repetitive Inspections for TFE731-2 and -2C Series Engines.For TFE731-2 and -2C series engines, do the following:(a) Measure throat dimensions, air flow and determine serviceability of the LPT stage 1 nozzle assembly using paragraphs 2.A.(3) through 2.A.(5) of Honeywell International Inc. SB No. TFE731-72-3369RWK, Revision 6.(b) If necessary, adjust the LPT stage 1 nozzle assembly using paragraph 2.B of Honeywell International Inc. SB No. TFE731-72- 3369RWK, Revision 6, or replace with a serviceable LPT stage 1 nozzle assembly. |\n| | 3. Disc Replacement for TFE731-3, -3A, -3AR, and -3R Series Engines.For TFE731-3, -3A, - 3AR, and -3R series engines with LPT stage 1 disc, P/N 3072351-All, 3073113-All, or 3074103-All, installed, replace the LPT stage 1 disc with a serviceable disc.4. Disc Replacement for TFE731-3B and -3BR Series Engines.For TFE731-3B and -3BR series engines do the following:(a) Replace LPT stage 1 disc, P/N 3073497-All, with a serviceable LPT stage 1 disc.(b) Perform the actions specified in requirement (4) (a) of this Directive, by converting the TFE731-3B and -3BR series engines to a TFE731- 3C series engine. This conversion allows the installation of a serviceable LPT stage 1 disc.Optional Terminating ActionAs optional terminating action to the repetitive inspections required by this Directive, replace the applicable LPT stage 1 disc with a more robust serviceable disc. Information on installing a serviceable disc can be found in Honeywell International Inc. SB No. TFE731-72-3704, SB No. TFE731-72-3705 and SB No. TFE731-72-3706 all dated 15 September 2004.DefinitionsFor the purposes of this Directive:(a) Next access to the LPT stage 1 nozzle assembly is defined as when the low-pressure tie-shaft is unstretched.(b) A serviceable LPT stage 1 disc is defined as a disc having a part number not listed in this Directive.(c) A serviceable LPT stage 1 nozzle assembly is defined as an LPT stage 1 nozzle assembly that passes the acceptance referenced in requirements (1)(a) and (2)(a) of this Directive.Alternative Method of Compliance (AMOC)An Alternative Method of Compliance (AMOC) to FAA 2005-05-15 Amdt 39-14004, approved by the United States Federal Aviation Administration (FAA) and issued after the effective date of the original issue of this Airworthiness Directive, is considered acceptable for compliance with the equivalent requirements of this AD.An Alternative Method of Compliance (AMOC) to this Airworthiness Directive, approved by CASA and issued after the effective date of the original issue of this Airworthiness Directive, is considered acceptable for compliance with the equivalent requirements of this AD.Note 2: FAA AD 2005-05-15 Amdt 39-14004 refers. |\n| Compliance: | 1. Initial Inspection for TFE731-2 and -2C Series Engines.At the next major periodic inspection (MPI) or at next access to the LPT stage 1 nozzle assembly, after the effective date of this AD, whichever occurs first, but not to exceed 2,200 hours time-in-service (TIS) since the last LPT stage 1 nozzle assembly inspection.2. Repetitive Inspections for TFE731-2 and -2C Series Engines.Thereafter at every MPI, but not to exceed 2,200 hours TIS since the last LPT stage 1 nozzle assembly inspection.3. Disc Replacement for TFE731-3, -3A, -3AR, and -3R Series Engines.At the next MPI, or at next access to the LPT stage 1 nozzle assembly, after the effective date of this Directive, or before December 31, 2011, whichever occurs first.4. Disc Replacement for TFE731-3B and -3BR Series Engines.At the next MPI, or at next access to the LPT stage 1 nozzle assembly, after the effective date of this Directive, or before December 31, 2011, whichever occurs first. |\n| | This Amendment becomes effective on 23 December 2011.The original issue of this Airworthiness Directive became effective on 4 August 2005. |\n| Background: | This Directive results from a report of an uncontained failure of the LPT stage 1 disc installed in a TFE731-3-1H turbofan engine. The actions detailed in this Directive are intended to prevent additional uncontained failure of the LPT stage 1 disc, and possible damage to the aeroplane. |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n21 December 2011","sortOrder":0},{"sectionNumber":"AD/TFE 731/33 Amdt 1","sectionType":"part","heading":"AD/TFE 731/33 Amdt 1","content":"## AD/TFE 731/33 Amdt 1","sortOrder":1},{"sectionNumber":"LPT Stage 1 Nozzle and Disks","sectionType":"part","heading":"LPT Stage 1 Nozzle and Disks","content":"## LPT Stage 1 Nozzle and Disks","sortOrder":2},{"sectionNumber":"26/2011","sectionType":"part","heading":"26/2011","content":"## 26/2011","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"},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":false,"description":"This is an amendment (Amdt 1) to an existing AD, which is standard practice for aviation safety directives. The scope remains tightly focused on the original safety issue (LPT stage 1 disc failures) and does not appear to have expanded beyond the original intent of preventing uncontained engine failures. The amendment likely clarifies compliance dates, updates service bulletin references, or refines applicability."},"complexity_factors":["Multiple engine series with different requirements (-2/-2C vs -3 variants vs -3B/-3BR)","Cross-references to three specific Honeywell Service Bulletins with precise revision numbers and dates","Conditional compliance timelines using 'whichever occurs first' logic","Nested definitions section with three technical terms defined for AD purposes","Alternative compliance pathways (AMOC provisions) referencing both FAA and CASA approvals","Part number ranges using '-All' suffix notation requiring interpretation","Dual effective dates (original issue 2005, amendment 2011) with different compliance triggers"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections and/or replacement of low‑pressure turbine (LPT) stage‑1 discs and nozzles on certain Honeywell TFE731 engines that power business jets (Dassault Falcon, Learjet, Cessna Citation, etc.). \n\nIt responds to an uncontained engine failure and requires owners/operators of affected engines to carry out specified maintenance or install a more robust disc to eliminate the recurring inspection requirement — preventing potential catastrophic in‑flight damage."},"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"This amendment (effective 23 December 2011) updates the original AD (first issued 4 August 2005) by prescribing specific inspection procedures tied to Honeywell SB Revision 6, adding mandatory disc replacements for certain TFE731-3 series variants, setting a 2,200 hours TIS recurring-inspection limit and calendar deadlines (see Requirements and Compliance). It therefore refines and extends the original instrument's obligations by adding explicit replacement timing, procedural references, and an optional terminating action (see Optional Terminating Action and AMOC)."},"complexity_factors":["Wide applicability across many engine variants and multiple part numbers (Applicability).","Different mandated actions depending on engine series: nozzle inspection/adjustment for -2/-2C; mandatory disc replacement for -3 family variants (Requirements 1–4).","External normative references: inspection and adjustment procedures are tied to specific paragraphs of Honeywell Service Bulletin No. TFE731-72-3369RWK, Revision 6 (Requirements 1–2).","Multiple compliance triggers and timing rules: next major periodic inspection (MPI) or next access, and a separate 2,200 hours TIS limit for inspections (Compliance 1–2).","Hard calendar deadlines for disc replacement for some series (before 31 December 2011) in addition to MPI/next-access triggers (Compliance 3–4).","Optional terminating action that requires installing more robust serviceable discs via other specified Honeywell SBs (Optional Terminating Action).","Definitions that alter compliance scope (e.g., what counts as 'next access' and what is a 'serviceable' disc) can change when and how actions apply (Definitions).","Cross-jurisdictional AMOC mechanism referencing FAA approvals and CASA approvals introduces regulatory discretion and coordination (AMOC).","Amendment/effective-date layer: this is Amdt 1 with an effective date (23 December 2011) building on an original 2005 AD, creating versioning to track compliance obligations (Effective date / Background)."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Honeywell (AlliedSignal/Garrett) TFE731 turbofan engines to inspect and, if needed, adjust or replace low-pressure turbine (LPT) stage 1 nozzle assemblies, and to replace certain LPT stage 1 discs by set deadlines. It applies to listed engine models and part numbers and sets inspection intervals and mandatory replacement timing to reduce the risk of uncontained disc failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks","history":"/api/acts/ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks/history","analysis":"/api/acts/ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks/analysis","conflicts":"/api/acts/ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks/conflicts","importantCases":"/api/acts/ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks/important-cases","documents":"/api/acts/ad-tfe-731-33-amdt-1-lpt-stage-1-nozzle-and-disks/documents"}}