{"id":"F2006B01983","name":"AD/A320/94 Amdt 1 - Reinforcement of Frame 35 between Stringers 30 and 31","slug":"ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41205,"registerId":"commonwealth-F2006B01983-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/A320/94 Amdt 1 - Reinforcement of Frame 35 between Stringers 30 and 31","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \n\nAIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/A320/94 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nAirbus Industrie A319, A320 and A321 Series Aeroplanes\n\nAD/A320/94\n\nAmdt 1\n\n  \n\nReinforcement of Frame 35 between Stringers 30 and 31\n\n  \n3/2002\n\nApplicability: All Model A320-111, -211, and -231 aircraft, except aircraft which have received Airbus Industrie modification 20903 in-production or Service Bulletin A320-53-1137 in-service.\n\nRequirement: Replace the affected fasteners after inspection of the fastener holes, in accordance with Airbus Industrie Service Bulletin A320-53-1137, Revision 2.\n\nNote: DGAC AD 2002-032(B) refers.\n\nCompliance: Before the accumulation of 18,400 flight cycles or within 3,500 flight cycles after 21 March 2002, whichever occurs later, without exceeding 20,000 total flight cycles; unless already accomplished.\n\nThis amendment becomes effective on 21 March 2002.\n\nBackground: During full-scale fatigue test, cracks were found at rivet holes located at FR35, between STGR30 and STRG31, left and right hand sides. This Directive provides reinforcement of the affected area.\n\nAmendment 1 is issued in response to a new DGAC AD which revises the threshold for accomplishment of the required modification. This action results from a survey of the A320 fleet, which highlighted some differences between the mission parameters of in-service aircraft and those originally considered.\n\nThe original issue of this Airworthiness Directive became effective on 16 July 1998.\n\n![](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 8 February 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 27 February 2002.\n\n  \nPage 1 of 1","sortOrder":0}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment maintains the original scope — reinforcing a specific structural area on specific Airbus models. The amendment only adjusts the compliance timeline based on updated fleet data; it does not expand the types of aircraft covered or introduce new categories of requirements."},"complexity_factors":["Multiple conditional compliance deadlines ('whichever occurs later', 'unless already accomplished')","Cross-reference to external technical document (Airbus Service Bulletin A320-53-1137 Revision 2) without reproducing its contents","Specific aircraft model numbers and modification status exceptions to applicability","Reference to foreign aviation authority directive (DGAC AD 2002-032(B))","Technical aviation terminology requiring domain knowledge (flight cycles, stringers, frames, fasteners)"],"plain_english_summary":"This safety order requires operators of Airbus A320-111, -211 and -231 aeroplanes to inspect and replace specified rivets between Frame 35 and Stringers 30/31 per Airbus Service Bulletin A320-53-1137 Rev 2. It responds to fatigue-test cracks found around rivet holes that could jeopardize structural integrity. Required action applies to unmodified aircraft and must be done by the specified flight-cycle deadlines (effectively before 20,000 total cycles)."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 1 does not expand the AD’s substantive scope (it still targets the same A320 sub-models and the same structural area). It adjusts the compliance threshold/timing in response to a DGAC AD and fleet survey — i.e. it changes when the mandated work must be done, not which aircraft or what action is required. The applicability, required technical action (per the Airbus service bulletin), and objective (reinforce Frame 35 between Stringers 30 and 31) remain the same."},"complexity_factors":["Short single-airworthiness-directive format (one-page AD)","Simple applicability clause with one clear exemption (aircraft with mod 20903 in-production or Service Bulletin A320-53-1137 already applied)","Single mandated action that defers to an external technical document (Airbus Service Bulletin A320-53-1137, Revision 2)","Two-part timing condition (before 18,400 flight cycles OR within 3,500 cycles after 21 March 2002, whichever is later) plus an absolute cap (do not exceed 20,000 total flight cycles)","Cross-reference to an external regulator’s AD (DGAC AD 2002-032(B))","Administrative elements: revocation of prior AD and effective date","No lengthy defined-terms section or multiple nested exceptions"],"plain_english_summary":"**What this directive does (mechanics)\n\n- Requires inspection of the fastener holes and replacement of the affected fasteners at Frame 35 between Stringers 30 and 31 on certain A320 family aeroplanes.  Work must be carried out in accordance with Airbus Industrie Service Bulletin A320-53-1137, Revision 2.  (See the “Requirement” section.)\n\n- Applies to all Airbus A320-111, -211 and -231 aircraft, except those that already received Airbus modification 20903 in production or that have already had Service Bulletin A320-53-1137 applied in service. (See the “Applicability” section.)\n\n- Sets the compliance timing: complete the work before the aircraft reaches 18,400 flight cycles, or within 3,500 flight cycles after 21 March 2002, whichever is later — but do not exceed 20,000 total flight cycles. (See the “Compliance” section.)\n\n- Becomes effective 21 March 2002. The earlier AD (AD/A320/94) is revoked and replaced by this Amendment 1.\n\n**Why the regulator issued it (stated rationale)\n\n- During full-scale fatigue testing, cracks were found at rivet holes at Frame 35 between Stringers 30 and 31 (both left and right sides). The directive requires reinforcement and replacement of affected fasteners to correct that unsafe condition. (See the “Background” and “Requirement” sections.)\n\n- Amendment 1 adjusts the compliance threshold in line with a new DGAC (French authority) AD and a fleet survey that showed in-service mission parameters differed from those previously assumed.\n\n**Who is affected and what they must do\n\n- Affected parties: operators/owners of A320-111, -211 and -231 aircraft that have not already had the in-production modification (mod 20903) or the service bulletin action completed.\n\n- Required action: follow the Airbus service bulletin: inspect the specified fastener holes and replace the fasteners as directed.\n\n- When to act: schedule the work so it is completed within the flight-cycle limits stated above. Keep maintenance records showing compliance.\n\n**Practical consequences, costs and trade-offs (implementation lens)\n\n- Direct cost and burden: operators pay for inspection labour, parts, and the aircraft downtime needed to perform the modification. The work follows a published Airbus service bulletin, so turn-key technical instructions are provided (reducing technical uncertainty). (Requirement section.)\n\n- Timing constraint trade-off: the AD prescribes a flight-cycle window rather than an immediate grounding; this lets operators plan maintenance but concentrates work as affected aircraft approach the threshold. That can create scheduling pressure and short-term demand for parts/maintenance resources.\n\n- Incentives and substitution effects: operators who have the in-production modification or already followed the service bulletin are exempt, creating an incentive to adopt the permanent modification sooner during routine maintenance schedules. Parts suppliers and maintenance providers will receive concentrated business from operators that must comply.\n\n- Risk and implementation issues: effectiveness depends on correct inspection and replacement per the service bulletin; variation in operator fleet usage (mission cycles) motivated the revised thresholds. Availability of parts or maintenance slots could delay compliance and increase operational disruption.\n\n- Regulatory discretion and record-keeping: CASA (via its delegate) revoked the prior AD and issued this amendment under the civil aviation regulations; compliance must be documented to avoid regulatory action.\n\n**Cross-references and external instructions\n\n- The AD mandates work performed in accordance with Airbus Service Bulletin A320-53-1137, Revision 2, and notes the related DGAC AD 2002-032(B). Operators must follow the service bulletin’s technical instructions to meet the AD’s legal requirements. (Requirement and Note.)\n\n**Bottom line (concise)**\n\nThis airworthiness directive compels certain A320-series aircraft operators to inspect and replace fasteners around Frame 35 between Stringers 30 and 31 per Airbus’s service instructions, within specified flight-cycle limits, because cracks were found in fatigue testing. The immediate effect is a maintenance cost and scheduling requirement for affected operators; the intended effect is to reduce the risk of structural cracking in that area. (Applicability; Requirement; Compliance; Background; Amendment 1.)"}},"importantCases":[],"_links":{"self":"/api/acts/ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31","history":"/api/acts/ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31/history","analysis":"/api/acts/ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31/analysis","conflicts":"/api/acts/ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31/conflicts","importantCases":"/api/acts/ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31/important-cases","documents":"/api/acts/ad-a320-94-amdt-1-reinforcement-of-frame-35-between-stringers-30-and-31/documents"}}