{"id":"F2006B02683","name":"AD/B727/160 Amdt 2 - Lower Skin Panel at the Lower Row of Fasteners of Fuselage Lap Joints","slug":"ad-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41999,"registerId":"commonwealth-F2006B02683-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/160 Amdt 2 - Lower Skin Panel at the Lower Row of Fasteners of Fuselage Lap Joints","content":"![](image.001.png)\n\n![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\nFor the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B767/160 Amdt 1 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\n![](image.001.png)\n\nBoeing 727 Series Aeroplanes\n\nAD/B727/160\n\nAmdt 2\n\n  \n\nLower Skin Panel at the Lower Row of Fasteners of Fuselage Lap Joints\n\n  \n8/2002\n\nApplicability: Model Boeing 727 series aircraft, as listed in Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A, dated 15 March 2001.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 2002-07-09, Correction, Amdt 39-12703.\n\nCompliance: As specified in the Requirement Document, with a revised effective date of 11 July 2002.\n\nThe revised effective date remains unchanged by this issue. This amendment becomes effective on 8 August 2002.\n\nBackground: The FAA received a report of a 20- inch fatigue crack in the lower skin panel of the fuselage, between BS 540 and BS 560 common to stringer S26L, at the lower row of fasteners in the lap joint. Further investigation revealed multiple site fatigue damage (approximately 80 cracks) in the stringer S-4R lap joint of the lower fastener row of the lower skin panel. Three out of four aircraft inspected were found with such damage at the stringer S-4L joint. Preliminary results of the investigation revealed that the cracking had initiated at approximately 40,000 total flight cycles.\n\nAmendment 1 was prompted by reports of additional crack findings; and limited the applicability, added certain repetitive inspections, revised certain compliance times, and required certain modifications of the fuselage lap joints.\n\nAmendment 2 is issued in response to a Correction of the related FAA AD which corrects a typographical error in the STC number specified in paragraph (i) of the FAA AD. The FAA retained the effective date of the original AD issue, and therefore the revised effective date of Amendment 1 of this Directive is retained. This amendment requires no additional work.\n\nBoeing 727 Series Aeroplanes\n\nAD/B727/160 Amdt 2 (continued)\n\nThe original issue of this Airworthiness Directive became effective on 3 March 1999\\. Amendment 1 to this Airworthiness Directive became effective on 11 July 2002.\n\n![Signature of David Villiers, Delegate of the Civil Aviation Safety Authority.](image.002.jpeg)\n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 28 June 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 17 July 2002.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment makes no substantive change to the scope. It is purely administrative — correcting a typo in an STC number in the referenced FAA document. The applicability (Boeing 727 series), the safety issue (fatigue cracking in lap joints), and the required actions (inspections and modifications per Amendment 1) remain identical to Amendment 1."},"complexity_factors":["Heavy reliance on external documents: The actual technical requirements are not contained in this directive but are incorporated by reference to FAA AD 2002-07-09 and Boeing Service Bulletin 727-53A0222","Multiple amendment layers: References Amendment 1, original issue dates, and a correction to the FAA AD, creating a chain of referenced versions","Technical aviation terminology: Uses specific engineering terms (fuselage lap joints, stringer S26L, BS 540/560, Supplemental Type Certificate) without explanation","Dual effective dates: Distinguishes between the compliance effective date (11 July 2002) and the amendment effective date (8 August 2002)","Cross-regulatory dependency: Operates under CAR 1998 subregulation 39.1(1) and mirrors FAA regulatory action"],"plain_english_summary":"This CASA Airworthiness Directive mandates operators of Boeing 727s listed in Boeing Service Bulletin 727-53A0222 Rev 1 to follow FAA AD 2002-07-09: repetitive inspections and required repairs/modifications for fatigue cracking in lower skin panels at fuselage lap‑joint lower fasteners. The cracking (found after ~40,000 cycles) threatens fuselage integrity. Amendment 2 only corrects a typographical error in an STC number from the prior amendment and imposes no new work or compliance changes."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Amendment 2 did not materially change the scope of the AD. It only implements a Correction to the related FAA AD to fix a typographical error in the STC number and states that no additional work is required (Background and Amendment 2 text).  Note: Amendment 1 (prior to this amendment) did change scope earlier by limiting applicability, adding repetitive inspections and requiring certain modifications (Background), but Amendment 2 preserves the scope established by Amendment 1 rather than expanding it further."},"complexity_factors":["Short AD text (single-page style document)","Relies primarily on external technical documents: FAA AD 2002-07-09 and Boeing Service Bulletin 727-53A0222 Rev 1 (creates cross-reference complexity)","Three historical versions referenced (original AD, Amendment 1, Amendment 2) with Amendment 2 only correcting a typographical error","Applicability limited to aircraft listed in a specific service bulletin (narrow scope but requires checking external list)","Compliance timing delegated to the Requirement Document (conditional logic lives in the FAA AD rather than in this AD)","Background contains operational data (fatigue initiation at ~40,000 cycles) but no additional prescriptive detail in the AD itself"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- This is an Airworthiness Directive (AD) that applies to certain Boeing 727 series aeroplanes listed in Boeing Service Bulletin 727-53A0222, Revision 1, including Appendix A (Applicability section).\n- It requires operators to carry out the inspections, repetitive inspections, repairs and any required modifications that are set out in the referenced FAA Airworthiness Directive (FAA AD 2002-07-09, Correction, Amdt 39-12703) (Requirement section).\n- The timing for when those actions must be done is governed by the referenced Requirement Document; the AD states the revised effective date is retained and gives an effective date for this Australian amendment (Compliance section).  Amendment 2 itself corrects a typographical error in the FAA AD’s STC (supplemental type certificate) number and does not add new work (Background and Amendment 2 text).\n\n**Who this affects**\n\n- Owners and operators of Boeing 727 series aircraft that are listed in the Boeing Service Bulletin referenced in the Applicability section.  Those operators must follow the inspection and repair schedule in the FAA AD (Requirement section).\n- Maintenance organisations and engineers who perform the inspections, repairs and any required structural modifications on those aircraft.\n\n**Why it matters (stated safety concern and mechanical effect)**\n\n- The FAA investigation found fatigue cracking in the lower skin panel at the lower row of fasteners in fuselage lap joints, including a report of a 20‑inch crack and many smaller cracks; cracking appeared to start at about 40,000 total flight cycles (Background).  Cracks of this type can reduce structural integrity of the fuselage in the affected area.\n- The AD mandates inspections and corrective action to detect and repair that fatigue cracking, and in some cases to require modification or repetitive inspection intervals to manage recurrence (Requirement; Amendment 1 description in Background).\n\n**Who pays, who decides, and what behaviour changes**\n\n- Operators/owners pay: the cost of additional inspections, potential repairs, and any modifications required by the FAA AD (Requirement; Compliance).\n- The regulator (CASA, acting through its delegate) decides the AD is necessary and enforces compliance under the Civil Aviation Regulations powers (preamble text referring to subregulation 39.1(1) of CAR 1998).\n- Behaviour change: affected operators must schedule and perform the specified inspections and corrective actions per the FAA AD schedule and keep records to show compliance. Repetitive inspections or modifications may create ongoing maintenance obligations (Requirement; Compliance).\n\n**Implementation, incentives and trade-offs**\n\n- Implementation relies on an external, prescriptive technical document (the FAA AD and Boeing Service Bulletin). That centralises technical detail outside the AD itself (Requirement; Applicability).  This reduces duplication but requires operators to obtain and follow the external documents.\n- Cost concentration: the direct financial burden falls on the relatively small, identifiable group of Boeing 727 operators listed in the Service Bulletin (Applicability).  Costs include labour, parts and downtime for inspections/repairs.\n- Compliance risk and enforcement: failure to comply with an AD risks regulatory enforcement and may ground affected aircraft. The AD does not itself specify inspection procedures in full — it mandates following the FAA AD — so variation in how maintenance providers execute the work is possible (Requirement).\n- Opportunity cost: resources devoted to these inspections and repairs are diverted from other maintenance or operation uses. If modifications are required, owners may also face longer-term maintenance or performance implications.\n- Implementation burden: Amendment 1 (described in the Background) added repetitive inspections and certain modifications; Amendment 2 only corrects a typographical error and imposes no further work (Background).\n\n**Net practical effect**\n\n- For the operators listed, the AD preserves aircraft safety by requiring detection and repair of fatigue cracking in a specific fuselage area. The paperwork is concise; the substantive technical burden is in the FAA AD and Boeing Service Bulletin that the AD references (Requirement; Applicability)."},"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-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints","history":"/api/acts/ad-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints/history","analysis":"/api/acts/ad-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints/analysis","conflicts":"/api/acts/ad-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints/conflicts","importantCases":"/api/acts/ad-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints/important-cases","documents":"/api/acts/ad-b727-160-amdt-2-lower-skin-panel-at-the-lower-row-of-fasteners-of-fuselage-lap-joints/documents"}}