{"id":"F2008L04175","name":"AD/A320/11 Amdt 2 - Engine Rear Mount Barrel Nuts","slug":"ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":76114,"registerId":"commonwealth-F2008L04175-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Airbus Industrie A319, A320 and A321 Ser","sectionType":"division","heading":"Airbus Industrie A319, A320 and A321 Series Aeroplanes","content":"### Airbus Industrie A319, A320 and A321 Series Aeroplanes\n\n| AD/A320/11 Amdt 2 | Engine Rear Mount Barrel Nuts | 13/2008 DM |\n| ----------------- | ----------------------------- | ---------- |\n\n| Applicability: | AIRBUS A319-131, A319-132, A319-133, A320-231, A320-232, A320-233,A321-131, A321-231 and A321-232 aircraft models, all serial numbers with IAE V2500-A1 or V2500-A5 engines installed.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. For aircraft with IAE V2500-A1 engines installed:a. Carry out the applicable documentation checks and establish if barrel nut part number (P/N) 83644-1612 may be installed, in accordance with paragraph 5.1 of Airbus All Operator Telex (AOT) A320-71A1045, dated17 October 2008 or later.b. For aircraft on which the correct standard of installation cannot be established by data records, or where data records indicate the affected part may be installed - carry out the visual inspections in accordance with paragraph 5.2 of Airbus AOT A320-71A1045, dated 17 October 2008 or later, and:(i) if one or more barrel nuts are found broken contact Airbus for corrective actions and embody these, or(ii) if two or more barrel nuts P/N 83644-1612 are found installed, correct the installation in accordance with paragraph 5.2 of Airbus AOTA320-71A1045, dated 17 October 2008 or later, or(iii) if only one barrel nut P/N 83644-1612 is found installed, remove and replace in accordance with paragraph 5.2 of Airbus AOTA320-71A1045, dated 17 October 2008 or later.c. Do not install engine mount barrel nuts P/N 83644-1612 on an aircraft.2. For aircraft with IAE V2500-A5 engines installed:a. Carry out the applicable documentation checks and establish if barrel nut part number (P/N) 83644-1612 may be installed, in accordance with paragraph 4.1 of Airbus AOT A320-71A1045, dated 17 October 2008 or later. |\n\n|             | b. For aircraft on which the correct standard of installation cannot be established by data records, or where data records indicate the incorrect part may be installed - carry out the visual inspections in accordance with paragraph 4.2 of Airbus AOT A320-71A1045, dated 17 October 2008 or later, and(i) if one or more barrel nuts are found broken contact Airbus for corrective actions and embody these, or(ii) if two or more barrel nuts P/N 83644-1612 are found installed, correct the installation in accordance with paragraph 4.2 of Airbus AOTA320-71A1045, dated 17 October 2008 or later, or(iii) if only one barrel nut P/N 83644-1612 is found installed, remove and replace in accordance with paragraph 4.2 of Airbus AOTA320-71A1045, dated 17 October 2008 or later.c. Do not install engine mount barrel nuts P/N 83644-1612 on an aircraft.Note: EASA AD 2008-0191-E dated 20 October 2008 refers. This AD supersedes DGAC AD 90-079-009(B) R1 dated 6 July 1991. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | For Requirement 1.a. - Within 7 days after the effective date of this AD, unless previously accomplished.For Requirement 1.b. - Within 7 days after the effective date of this AD, unless previously accomplished.For Requirement 1.b.(i) and 1.b.(ii) - Before further flight.For Requirement 1.b.(iii) - Within 1,200 Flight Hours or 960 Flight Cycles since installation of the part, whichever occurs first.For Requirement 1.c. - After the effective date of this AD.For Requirement 2.a. - Within 7 days after the effective date of this AD, unless previously accomplished.For Requirement 2.b. - Within 7 days after the effective date of this AD, unless previously accomplished.For Requirement 2.b.(i) and 2.b.(ii) - Before further flight.For Requirement 2.b.(iii) - Within 1,200 Flight Hours or 960 Flight Cycles since installation of the part, whichever occurs first.For Requirement 2.c. - After the effective date of this AD.                                      |\n\n|             | This Amendment becomes effective on 29 October 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Background: | Cracking of the engine rear mount barrel nuts has been reported.Amendment 2 is in response to advice that Airbus has incorporated an incorrect part number in the Illustrated Parts Catalogue, (reference 71-22-11 Figure 80B item 180) for the rear engine mount barrel nut. This problem affects Airbus A319, A320 and A321 models with IAE V2500-A5 engines.The part number introduced in error is not certificated for the IAE V2500-A5 engine installation and, if installed, may fail in service. This amendment mandates the inspections required to determine the standard of barrel nut installed and the corrective actions, as necessary, for the aircraft with V2500-A1 or -A5 engines installed.Amendment 1 changed the applicability to only include those aircraft not modified or incorporating a certain service bulletin.Amendment 1 of this AD became effective on 28 October 2004.The original issue of this Directive became effective on 12 July 1990. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n24 October 2008","sortOrder":0},{"sectionNumber":"AD/A320/11 Amdt 2","sectionType":"part","heading":"AD/A320/11 Amdt 2","content":"## AD/A320/11 Amdt 2","sortOrder":1},{"sectionNumber":"Engine Rear Mount Barrel Nuts","sectionType":"part","heading":"Engine Rear Mount Barrel Nuts","content":"## Engine Rear Mount Barrel Nuts","sortOrder":2},{"sectionNumber":"13/2008 DM","sectionType":"part","heading":"13/2008 DM","content":"## 13/2008 DM","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The AD's scope has been modified from earlier versions. The Background states Amendment 2 was issued in response to an incorrect part number in the Illustrated Parts Catalogue affecting V2500-A5 installations and mandates inspections and corrective actions for aircraft with V2500-A1 or -A5 engines. It also states Amendment 1 previously changed applicability to only include aircraft not modified or incorporating a certain service bulletin. The current amendment therefore adjusts the affected part identification and the set of aircraft to which the directive applies compared with the original 1990 issue and earlier amendments (Background)."},"complexity_factors":["Multiple conditional branches depending on engine model (IAE V2500-A1 vs V2500-A5) with largely parallel requirements (Requirement 1 vs 2).","Initial reliance on documentation checks, with fallback to visual inspection when records are incomplete (Requirement 1.a/1.b and 2.a/2.b).","Different corrective timelines: immediate (before further flight) for some findings vs deferred replacement limits (1,200 flight hours or 960 flight cycles) for single-part findings (Compliance).","Dependency on external technical document (Airbus AOT A320-71A1045 dated 17 October 2008 or later) for inspection and corrective-action details, which requires operators to consult and follow manufacturer procedures (Requirement references).","Prohibition on future installation of a specific part number, requiring supply-chain and maintenance-process changes (Requirement 1.c and 2.c).","References to prior and superseded directives and amendments, requiring attention to amendment history for applicability (Background)."],"plain_english_summary":"### What this directive does\n\nThis airworthiness directive (AD) requires operators of certain Airbus A319, A320 and A321 aeroplanes fitted with International Aero Engines (IAE) V2500-A1 or V2500-A5 engines to check whether a specific engine rear mount barrel nut (part number 83644-1612) is installed, and to inspect and correct the installation if necessary. The directive also bans installing that barrel nut on these aircraft (see Requirement 1.c and 2.c).\n\nMechanically, the AD works like this:\n- Operators must check maintenance records to see whether barrel nut P/N 83644-1612 may be fitted (Requirement 1.a and 2.a).\n- If records do not establish the correct part, or if records indicate the affected part may be present, operators must carry out visual inspections following the procedures and timing set out in Airbus All Operator Telex (AOT) A320-71A1045 dated 17 October 2008 or later (Requirement 1.b and 2.b).\n- If broken barrel nuts are found, operators must contact Airbus and carry out Airbus’s corrective action (Requirement 1.b(i) and 2.b(i)).\n- If two or more of the affected barrel nuts are installed, the installation must be corrected before further flight (Requirement 1.b(ii) and 2.b(ii)).\n- If only one affected barrel nut is installed, it must be removed and replaced within 1,200 flight hours or 960 flight cycles since the part’s installation, whichever comes first (Requirement 1.b(iii) and 2.b(iii)).\n- The AD prohibits installing P/N 83644-1612 on the affected aircraft (Requirement 1.c and 2.c).\n\nWhy the rule was made (stated reason):\n- The background states that cracking of engine rear mount barrel nuts has been reported and that an incorrect part number was put in an Illustrated Parts Catalogue. The incorrect part number is not certificated for the V2500-A5 engine installation and, if installed, may fail in service. The AD therefore mandates checks, inspections and corrective actions to determine and correct the barrel nut standard (Background).\n\nWho is affected and who pays\n- Affected parties: operators/owners of AIRBUS A319-131/132/133, A320-231/232/233 and A321-131/231/232 aircraft with IAE V2500-A1 or V2500-A5 engines (Applicability).\n- Who decides/makes required technical choices: the AD requires operators to follow the Airbus AOT procedures; if broken nuts are found, operators must contact Airbus for corrective action (Requirement 1.b(i) and 2.b(i)). The AD itself is issued by the Civil Aviation Safety Authority (CASA) (signed by the Delegate) and references Airbus AOT A320-71A1045 dated 17 October 2008 or later.\n- Who pays: the operator/owner will bear the direct costs of checking records, performing visual inspections, removing or replacing parts and any induced aircraft downtime (implied by the inspection and before-further-flight corrective-action requirements in the Compliance section).\n\nTiming and enforcement mechanics\n- Most document checks and initial inspections must be done within 7 days after the AD’s effective date unless already done (Compliance: Requirements 1.a, 1.b, 2.a, 2.b).\n- Where corrective action is required because multiple affected nuts are fitted or broken nuts are found, that corrective action must be completed before the next flight in certain cases (Compliance: 1.b(i)/1.b(ii)/2.b(i)/2.b(ii)).\n- Where only one affected nut is installed, replacement may be deferred up to 1,200 flight hours or 960 flight cycles from installation, whichever occurs first (Compliance: 1.b(iii) and 2.b(iii)).\n\nCompliance burdens, incentives and implementation risks (mechanical assessment)\n- Record-dependence: The AD prioritises documentation checks first; where records are incomplete, operators must perform visual inspections per Airbus AOT paragraphs (Requirement 1.a/1.b and 2.a/2.b). This creates operational cost for record review and possible additional maintenance work where records do not provide a clear answer.\n- Inspection and labour costs: Visual inspections and any removals/replacements impose labour and parts cost and may put aircraft temporarily out of service (Compliance timing and corrective-action requirements).\n- Grounding/operational impact: In cases where two or more affected nuts are found or nuts are broken, the AD requires correction before further flight, which can cause immediate grounding until corrective action is completed (Requirement 1.b(ii)/2.b(ii) and 1.b(i)/2.b(i); Compliance: before further flight).\n- Reliance on manufacturer instructions: The AD requires operators to follow Airbus AOT A320-71A1045 (dated 17 October 2008 or later) for inspection details and corrective actions (Requirements reference that AOT). Operators therefore must implement Airbus-prescribed procedures and incorporate any later revisions of that AOT that are applicable under the AD’s wording.\n- Ban on future installation: The prohibition on installing the specified P/N (Requirement 1.c and 2.c) changes future parts-supply and maintenance choices; operators and parts suppliers must ensure the banned part is not used on these engine installations.\n\nTrade-offs and opportunity costs\n- The AD reduces the risk of in-service failure of an uncerta in barrel nut by requiring checks and correction, at the cost of inspections, replacements and potential aircraft downtime. The directive shifts the immediate compliance costs to operators and places technical instruction authority for corrective actions with Airbus (Requirement 1.b(i)/2.b(i)).\n\nReference to administrative history\n- The AD supersedes earlier directives (it supersedes DGAC AD 90-079-009(B) R1) and notes earlier amendments (Background). The amendment responds to an incorrect part number inclusion in an Airbus catalogue for V2500-A5 installations (Background). The AD became effective 29 October 2008 (Compliance/Effectivity).\n\nKey cited sections: Applicability; Requirement 1 and 2 (and subparagraphs); Compliance timings; Background; Effectivity and signature by CASA delegate."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original 1990 directive addressed cracking of engine rear mount barrel nuts generally. Amendment 1 in 2004 narrowed applicability to exclude modified aircraft. Amendment 2 significantly expanded the scope again by adding a new problem: an incorrect part number had been introduced into Airbus's official parts catalogue for V2500-A5 engines. This transformed the AD from a simple cracking inspection into a dual-purpose directive covering both material fatigue (original) and parts catalogue errors (new). The directive now covers two distinct engine variants (A1 and A5) with different inspection paragraphs, whereas earlier versions may have been more limited."},"complexity_factors":["Multiple parallel requirement streams for two different engine variants (V2500-A1 vs V2500-A5) with nearly identical but separately numbered paragraphs","Nested conditional logic: documentation checks trigger visual inspections, which trigger three different corrective action pathways based on findings","Multiple compliance timeframes: immediate (before further flight), 7-day window, and flight hours/cycles-based deadlines","Cross-references to external Airbus technical documents (AOT A320-71A1045) and prior regulatory versions (EASA AD 2008-0191-E, DGAC AD 90-079-009(B) R1)","Amendment history tracking (original 1990 issue, Amendment 1 in 2004, Amendment 2 in 2008) indicating evolving scope","Specific part number tracking (P/N 83644-1612) requiring precise technical identification"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires airlines and aircraft operators to inspect and fix a specific mechanical problem on certain Airbus passenger jets.\n\n**What the problem is:**\nThe engine rear mount barrel nuts (metal fasteners that help hold the engine to the wing) on some Airbus A319, A320, and A321 aircraft have been cracking. Worse, Airbus accidentally listed the wrong part number in its parts catalogue for some engine types. If the wrong barrel nut is installed, it could fail in flight — potentially causing the engine to detach or cause serious damage.\n\n**Which aircraft are affected:**\n- Airbus A319, A320, and A321 models with **IAE V2500-A1 or V2500-A5 engines**\n- All serial numbers of these specific models\n\n**What operators must do:**\n1. **Check the paperwork** within 7 days to see if the wrong part (P/N 83644-1612) might be installed\n2. **Visually inspect** the aircraft if records are unclear or suggest the wrong part is present:\n   - If any barrel nuts are **broken**: Contact Airbus immediately for repair instructions and fix before flying again\n   - If **two or more** wrong parts are found: Fix the installation before flying again\n   - If only **one** wrong part is found: Replace it within 1,200 flight hours or 960 flight cycles (whichever comes first)\n3. **Never install** the wrong part number on any aircraft going forward\n\n**Why this matters:**\nThis is a critical safety issue. The engine mount is what keeps the engine attached to the aircraft. A failed barrel nut could lead to catastrophic engine separation. The directive ensures potentially dangerous parts are identified and replaced before they fail."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts","history":"/api/acts/ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts/history","analysis":"/api/acts/ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts/analysis","conflicts":"/api/acts/ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts/conflicts","importantCases":"/api/acts/ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts/important-cases","documents":"/api/acts/ad-a320-11-amdt-2-engine-rear-mount-barrel-nuts/documents"}}