{"id":"F2016L00389","name":"AD/B737/16 Amdt 4 - Engine Flameouts – Revised Operating Technique and Modifications","slug":"ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":94387,"registerId":"commonwealth-F2016L00389-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 737 Series Aeroplanes","sectionType":"division","heading":"Boeing 737 Series Aeroplanes","content":"### Boeing 737 Series Aeroplanes\n\n| AD/B737/16 Amdt 4 | Engine Flameouts – Revised Operating Technique and Modifications | 7/2016 |\n| ----------------- | ---------------------------------------------------------------- | ------ |\n\n| Applicability: | All Boeing Model 737-300, 737-400 and 737-500 series aeroplanes fitted with CFM International CFM56-3 series engines.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | For Model 737-300 series aeroplanes:a. Perform the actions specified in paragraphs (a) (1), (a) (2), and (a) (3) of FAA AD 93-05-05.b. Perform the actions specified in paragraph (b) of FAA AD 93-05-05 by accomplishing the engine modification given in Boeing Service Bulletin 737‑77-1031, Revision 1.Incorporation of this modification constitutes terminating action for Requirement 1.a. of this AD. The associated Flight Manual revision, the Minimum Equipment List (MEL) configuration requirement, and the N1 placard may be removed concurrently.2. For Model 737-400 and 737-500 series aeroplanes:-a. Perform the actions specified in paragraph (c) of FAA AD 93-05-05 by accomplishing the engine modification given in Boeing Service Bulletin 737-77-1031, Revision 1.Upon incorporation of this modification, Flight Manual limitations pertaining to ”OPERATION IN MODERATE TO HEAVY RAIN, HAIL, OR SLEET” may be removed, as well as the related flight compartment instrument panel placard, related MEL configuration requirements, and any related 45% N1 idle indication/control limitations.Note 1: Compliance with the requirements of Amendment 3 to this AD constitutes compliance with the equivalent actions of this directive, AD/B737/16 Amdt 4.Note 2: FAA AD 93-05-05 Amdt 39-8510 refers. |\n\n| Compliance: | For Requirement 1.a. – Compliance times for equivalent actions taken in accordance with Amendment 3 to this Directive remain unchanged; For FAA AD 93-05-05 Para. (a) (1) and (a) (3): Prior to further flight after16 January 1989. For FAA AD 93-05-05 Para. (a) (2): Prior to further flight after 23 January 1989.For Requirement 1.b. and 2.a. – If not previously accomplished, before further flight from the commencement date of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This AD commences on 5 April 2016.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |\n| Background: | The FAA issued Telegraphic Airworthiness Directive (AD) T88-11-51 on May 27, 1988, establishing a minimum engine fan speed (N1) when 737 aircraft equipped with CFM56 engines were operated during flight in or near heavy precipitation. That AD was subsequently superseded by AD T88-13-51, Initial Issue and Revision 1 which raised the minimum N1 limitation to ensure that the engine would continue to operate in the presence of heavy concentrations of rain and hail. CFM developed engine modifications designed to improve the rain and hail ingestion capability of the CFM56, thus permitting the engine to operate in heavy rain and hail at flight idle speed without losing power. As a result, in 1993, AD T88-13-51R1 was superseded by AD 93-05-05, which mandated the incorporation of the engine modification and eliminated the N1 limitation.This Amendment makes editorial changes throughout the text to align the previously stated Requirements with FAA AD 93-05-05, which superseded AD 88-13-51R1. |\n\n![DAVID_W](image.001.png)\n\nWilliam M. David  \nDelegate of the Civil Aviation Safety Authority\n\n23 March 2016","sortOrder":0},{"sectionNumber":"AD/B737/16 Amdt 4","sectionType":"part","heading":"AD/B737/16 Amdt 4","content":"## AD/B737/16 Amdt 4","sortOrder":1},{"sectionNumber":"Engine Flameouts — Revised Operating Tec","sectionType":"part","heading":"Engine Flameouts — Revised Operating Technique and Modifications","content":"## Engine Flameouts – Revised Operating Technique and Modifications","sortOrder":2},{"sectionNumber":"7/2016","sectionType":"part","heading":"7/2016","content":"## 7/2016","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The Amendment makes editorial changes to align the Australian AD with FAA AD 93-05-05 and confirms the requirement to incorporate Boeing Service Bulletin 737-77-1031 Rev 1. It does not expand applicability beyond Boeing 737-300/400/500 with CFM56-3 engines or add new technical mandates; compliance obligations and the terminating-action mechanism remain as previously set."},"complexity_factors":["Cross-reference dependency on FAA AD 93-05-05 and prior Australian amendments (requires reading multiple instruments to confirm obligations).","Model-specific requirements: different actions for 737-300 versus 737-400/500 (adds conditional branches for compliance).","Terminating action structure: installing Boeing SB 737-77-1031 Rev 1 both mandates a hardware change and removes prior operational/placard/MEL limits.","Compliance timing variations: some actions required ‘prior to further flight’ with differing historical dates for earlier amendments.","Reliance on Boeing Service Bulletin for the technical modification (requires coordination with manufacturer maintenance data and approved embodiment).","Editorial alignment only: amendment adjusts wording rather than introducing new technical measures, so legal interpretation focuses on equivalence with FAA phrasing."],"plain_english_summary":"This airworthiness directive requires operators of Boeing 737-300/400/500 aeroplanes with CFM56-3 engines to follow specified FAA AD 93-05-05 operating actions and, for most aircraft, install the engine modification in Boeing Service Bulletin 737-77-1031 Revision 1. Once the modification is fitted, previous minimum N1 and weather-related flight limitations and associated MEL/placard requirements may be removed.\n\nAircraft owners/operators pay for the modification and manual/MEL updates; maintenance organisations perform the work. Compliance deadlines are model-specific and include ‘prior to further flight’ for some actions. This Amendment edits wording to align with FAA AD 93-05-05."},"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":false,"description":"This legislation maintains its original scope. The Background section explicitly states this Amendment makes only \"editorial changes\" to align with the FAA directive. The core purpose — preventing engine flameouts in precipitation through operational procedures and/or physical modifications — remains unchanged from the original 1988/1993 intent. The document notes that compliance with Amendment 3 already satisfies the equivalent actions, indicating continuity rather than expansion."},"complexity_factors":["Heavy reliance on external references: The directive incorporates by reference FAA AD 93-05-05 and Boeing Service Bulletin 737-77-1031, meaning the full requirements are not contained in this document alone","Multiple aircraft variants with different requirements: The directive splits requirements between 737-300 series (Requirements 1.a and 1.b) and 737-400/500 series (Requirement 2.a), with slightly different compliance outcomes for each","Nested compliance timelines: Different deadlines for different paragraphs of the referenced FAA AD (January 16, 1989 vs January 23, 1989) plus a general \"before further flight\" requirement for the modifications","Conditional terminating actions: The modification constitutes \"terminating action\" for certain requirements, triggering concurrent removal of multiple associated documents (Flight Manual revisions, MEL configurations, placards)","Amendment tracking: References to Amendment 3 and Amendment 4 create a version history that operators must track to determine if previous compliance counts"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of Boeing 737-300/-400/-500 \"Classic\" aircraft with CFM56-3 engines in Australia to address engine flameout risk in heavy rain, hail or sleet—either by following legacy operational limits or by installing manufacturer airframe/engine modifications.  \n\nIt matters because the fixes eliminate a long‑standing precipitation-induced shutdown hazard and allow removal of previous flight manual restrictions and cockpit placards once completed."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications","history":"/api/acts/ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications/history","analysis":"/api/acts/ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications/analysis","conflicts":"/api/acts/ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications/conflicts","importantCases":"/api/acts/ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications/important-cases","documents":"/api/acts/ad-b737-16-amdt-4-engine-flameouts-revised-operating-technique-and-modifications/documents"}}