{"id":"F2005L01351","name":"AD/B747/281 Amdt 1 - Upper Deck Floor Beam Upper Chord and Web","slug":"ad-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":35141,"registerId":"commonwealth-F2005L01351-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 747 Series Aeroplanes","sectionType":"division","heading":"Boeing 747 Series Aeroplanes","content":"### Boeing 747 Series Aeroplanes\n\n| AD/B747/281 Amdt 1 | Upper Deck Floor Beam Upper Chord and Web | 7/2005 |\n| ------------------ | ----------------------------------------- | ------ |\n\n| Applicability: | Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR series aircraft, line numbers 1 through 810; and not equipped with a nose cargo door.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with the technical requirements of FAA AD 2005-06-12 Amdt 39-14020.Note: Boeing Alert Service Bulletins 747-53A2459 original issue, 747-53A2459 Revision 1, or a later FAA approved revision, refer.                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |\n| Compliance:    | As specified in the Requirement document, with a revised effective date of 7 July 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |\n|                | This Amendment becomes effective on 7 July 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| Background:    | The manufacturer received several reports of cracked upper deck floor beam upper chords on two aircraft. The upper deck floor beams connect to the body frames in the flat sided area of the upper body, and cracking in the floor beams could extend and sever floor beams adjacent to the body frame and result in rapid decompression of the aircraft.Amendment 1 is issued in response to a new FAA AD, which expands the existing inspection area and requires inspecting fastener holes in certain areas of aircraft modified previously, and taking corrective action if necessary. The AD was prompted by reports of fatigue cracking of the upper chord of certain upper deck floor beams. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n26 May 2005","sortOrder":0},{"sectionNumber":"AD/B747/281 Amdt 1","sectionType":"part","heading":"AD/B747/281 Amdt 1","content":"## AD/B747/281 Amdt 1","sortOrder":1},{"sectionNumber":"Upper Deck Floor Beam Upper Chord and We","sectionType":"part","heading":"Upper Deck Floor Beam Upper Chord and Web","content":"## Upper Deck Floor Beam Upper Chord and Web","sortOrder":2},{"sectionNumber":"7/2005","sectionType":"part","heading":"7/2005","content":"## 7/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"Yes. Amendment 1 increases the scope relative to the original AD by expanding the inspection area and adding a requirement to inspect fastener holes in certain previously modified areas, as reported in the Background. That expands the set of structural locations and potentially the number of aircraft/parts requiring inspection and corrective action compared with the earlier directive."},"complexity_factors":["Cross-reference to FAA AD 2005-06-12 (external normative document) rather than full technical steps included in the instrument","Reference to Boeing Alert Service Bulletin 747-53A2459 and any later FAA-approved revisions (dependency on multiple document revisions)","Applicability limited by model types, line number range (1–810) and equipment exclusion (not equipped with a nose cargo door)","Amendment expands inspection area and adds inspection of fastener holes in previously modified areas (additional conditional inspection locations)","Technical specificity (exact inspection intervals, methods, and corrective actions) delegated to the referenced FAA/SB documents rather than stated in the AD"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Orders operators of certain older Boeing 747 models to carry out inspections and corrective action on the upper deck floor beam upper chord and web in accordance with FAA Airworthiness Directive (AD) 2005-06-12 and the Boeing Alert Service Bulletin 747-53A2459 (original, Revision 1, or later FAA-approved revisions). (See \"Requirement\".)\n- Sets the compliance timing to follow the referenced FAA AD, with this Australian amendment effective from 7 July 2005. (See \"Compliance\".)\n\n**Which aeroplanes are affected**\n\n- Applies to Boeing 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP and 747SR series aircraft, line numbers 1–810, that are not fitted with a nose cargo door. (See \"Applicability\".)\n\n**Why it matters (safety risk and trigger)**\n\n- The manufacturer reported multiple instances of fatigue cracking in the upper chord of upper deck floor beams. Those beams tie into the fuselage frames; cracks can propagate, potentially sever floor beams adjacent to body frames and lead to rapid decompression. The Background section says Amendment 1 was issued because the FAA AD expanded the inspection area and added inspection of fastener holes in some previously modified areas.\n\n**Who pays and who decides**\n\n- Aircraft owners/operators are responsible for performing the inspections and any corrective actions (repairs, replacements) required by the FAA AD and the referenced Boeing service documents. Approved maintenance organisations perform the physical work and must document compliance. The Civil Aviation Safety Authority enforces the AD in Australia. (See \"Requirement\" and \"Compliance\".)\n\n**How it changes operator behaviour (mechanics and incentives)**\n\n- Operators must schedule and perform the mandated inspections and repairs; that creates direct costs (labour, spare parts, potential structural repair) and aircraft downtime. Those costs fall on the aircraft operator or lessee.\n- Where inspections reveal cracking or other defects, operators must carry out corrective action to meet the AD. That may include repetitive inspections, structural repair, or parts replacement as specified by the FAA AD/service bulletin.\n- Operators have an incentive either to comply promptly or to ground/withdraw affected aircraft pending repair; non-compliance risks regulatory enforcement and airworthiness restrictions.\n\n**Implementation, compliance burden and risks**\n\n- The AD delegates the technical detail to FAA AD 2005-06-12 and Boeing Alert Service Bulletin 747-53A2459 (including later FAA-approved revisions). That reduces the need for technical specification within the Australian instrument but creates cross-jurisdictional dependency: the exact inspection procedures, thresholds and repair instructions are in external documents.\n- Compliance burden includes familiar regulatory paperwork, inspections to the specified areas (now expanded under Amendment 1), potential repeat inspections, and corrective actions where cracks or fastener issues are found.\n- Operational costs include labour, parts, inspection tooling, and aircraft out-of-service time. Smaller operators of vintage 747s may feel these costs more acutely; larger operators may scale inspections across fleets.\n- There is a practical implementation risk in ensuring that maintenance organisations use the FAA-approved revision of the Boeing service bulletin cited by the AD.\n\n**Trade-offs and opportunity costs**\n\n- The safety objective is to detect and correct fatigue cracking before catastrophic structural failure or rapid decompression can occur. The trade-off is higher maintenance cost, inspection scheduling complexity and potential short-term removal of aircraft from service.\n- Some operators may elect longer-term options (for example, expensive structural modification, retirement, or transfer of affected airframes) rather than repeated inspections and repairs.\n\n**Where the instrument expanded scope compared with the earlier AD**\n\n- The Background states that Amendment 1 responds to a new FAA AD that \"expands the existing inspection area and requires inspecting fastener holes in certain areas of aircraft modified previously.\" That increases the number of locations to be inspected and may capture aircraft that were previously considered compliant under the original AD. (See \"Background\".)\n\n**Primary references in the instrument**\n\n- Applicability (which models and line numbers).\n- Requirement (FAA AD 2005-06-12 and Boeing Alert Service Bulletin 747-53A2459 or later FAA-approved revisions).\n- Compliance (follow the Requirement document; effective date 7 July 2005).\n- Background (reason for amendment: reports of fatigue cracking and the FAA's expanded inspection scope).\n\nIn short: this Australian amendment requires older, non-nose-cargo-door Boeing 747s (line numbers 1–810) to follow the FAA AD and Boeing service bulletin inspection and repair regime for upper deck floor beam upper chord and web fatigue cracking. Operators bear inspection and repair costs, and the amendment widens inspection scope compared with the earlier AD to include additional areas and fastener holes identified by the FAA."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"This Amendment 1 expands the scope beyond the original directive. The background explicitly states it 'expands the existing inspection area and requires inspecting fastener holes in certain areas of aircraft modified previously.' The original likely covered only initial inspections; this version adds follow-up inspections for already-modified aircraft and broadens the physical inspection area based on new FAA data about where cracks occur."},"complexity_factors":["Short, single-purpose document (1 page)","Only 4 defined elements: applicability criteria, requirement reference, compliance date, and background","Heavy reliance on external technical documents (FAA AD 2005-06-12 and Boeing Service Bulletins) rather than spelling out requirements in full","Simple conditional logic: applies to specific model numbers AND excludes nose cargo door variants","No nested exceptions or cross-references to other Australian legislation"],"plain_english_summary":"This is an **airworthiness directive** (a mandatory safety order) for certain Boeing 747 aircraft. It requires airlines and aircraft operators to inspect specific parts of the upper deck floor beams—the metal supports beneath the upper floor of the plane—for cracks.\n\n**What happened:** The manufacturer found cracks in the upper chords (top horizontal supports) of floor beams on two aircraft. These beams connect to the aircraft's body frames, and if cracks spread, they could sever multiple beams and cause **rapid decompression** (sudden loss of cabin pressure at altitude).\n\n**What this directive does:**\n- **Expands inspection areas** compared to the previous version\n- Requires checking fastener holes in aircraft that were already modified under earlier rules\n- Mandates repairs if cracks are found\n- Applies to specific 747 models (100, 200B, 300, SP, and SR series, line numbers 1–810) that don't have a nose cargo door\n\n**Who must comply:** Airlines and operators flying these specific Boeing 747 models.\n\n**Why it matters:** Fatigue cracking in structural components can lead to catastrophic failure. This directive prevents potential accidents by catching cracks before they spread."},"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-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web","history":"/api/acts/ad-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web/history","analysis":"/api/acts/ad-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web/analysis","conflicts":"/api/acts/ad-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web/conflicts","importantCases":"/api/acts/ad-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web/important-cases","documents":"/api/acts/ad-b747-281-amdt-1-upper-deck-floor-beam-upper-chord-and-web/documents"}}