{"id":"F2006B02630","name":"AD/B727/107Amdt 2 - MLG Wheel Well Pressure Floor","slug":"ad-b727-107amdt-2-mlg-wheel-well-pressure-floor","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41946,"registerId":"commonwealth-F2006B02630-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/107Amdt 2 - MLG Wheel Well Pressure Floor","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Boeing 727 Series Aeroplanes\n\n \n\n# AD/B727/107\n\nAmdt 2\n\nApplicability: All Models.\n\n# MLG Wheel Well Pressure Floor 3/93\n\n \n\nRequirement: Inspect and repair the pressure floor of the MLG wheel well in accordance with FAA AD 92-19-11.\n\n \n\nNote: Boeing Service Bulletin 727-53-0149 Revision 4 refers.\n\n \n\nCompliance: For BS 880, 890, 930 and 940, inspect before 20000 flights, or within 4000 flights since the last visual or dye penetrant inspection, or within 5000 flights since the last eddy current inspection, or within 2500 flights after 7 January 1993, whichever occurs last.\n\n \n\nFor BS 950, inspect before 20000 flights, or within 2500 flights after 4 March 1993, whichever occurs later.\n\n \n\nFor all areas, re-inspect at intervals no longer than 4000 flights after each visual or dye penetrant inspection, or no longer than 5000 flights after each eddy current inspection, until repaired or modified in accordance with paragraph (h) of FAA AD 92-19-11. Inspect cracked and repaired structure and replace blind rivets at the times shown in paragraphs (e), (f) and (g) of FAA AD 92-19-11.\n\n \n\nBackground: This Directive was originally issued in response to overseas reports of cracking of the MLG wheel well pressure floor which resulted in loss of cabin pressurisation.\n\nAmendment 1 reduced the initial inspection threshold, introduced a requirement for further repeat inspections on aircraft previously modified, and limited the life of interim repairs accomplished using blind fasteners. This amendment has been raised in response to reports of cracking at BS 950 and expands the inspection area to include this location. Incorporation of the terminating modification is recommended for aging Boeing 727 Aeroplanes.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"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"},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"Yes. The Directive's scope and compliance burden have been tightened since the original issue: Amendment 1 reduced initial inspection thresholds, added repeat inspections for previously modified aircraft and limited the life of interim repairs using blind fasteners; the current amendment expands the inspection area to include BS 950. Practically, more operators (owners of BS 950 aeroplanes) are covered and all affected operators must perform more frequent or earlier inspections, repairs, blind‑rivet replacements and may be recommended to adopt the terminating modification. The Civil Aviation Safety Authority issues the directive; aircraft owners/operators bear the cost and must change maintenance planning and recordkeeping to comply."},"complexity_factors":["Cross‑reference dependency on FAA AD 92‑19‑11 for detailed inspection, repair, rivet replacement and terminating modification requirements (paragraphs e, f, g, h referenced).","Multiple aircraft build series (BS 880, 890, 930, 940, 950) with distinct initial compliance thresholds and dates.","Different inspection methods (visual, dye‑penetrant, eddy‑current) carry different inspection intervals and trigger points.","Repeat inspection regime: recurring inspections at method‑dependent intervals until repair or modification is accomplished.","Historical amendments altered thresholds and introduced life limits for interim repairs, requiring attention to amendment history when determining current obligations.","Reference to Boeing Service Bulletin 727‑53‑0149 Revision 4 as a related source increases documentation that operators must consult.","Operational compliance requires tracking flight counts per aeroplane and maintenance history to establish which deadline applies."],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 727 aeroplanes to inspect and repair the main landing gear (MLG) wheel‑well pressure floor in line with FAA AD 92‑19‑11. It sets different initial and repeat inspection deadlines depending on aircraft build series (BS 880/890/930/940/950) and inspection method (visual, dye‑penetrant, eddy‑current). \n\nIt affects aircraft owners/operators, who must fund inspections, repairs, blind‑rivet replacements and any recommended terminating modification to prevent loss of cabin pressurisation."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"The original directive addressed cracking at specific body stations (880, 890, 930, 940). Amendment 1 expanded this by reducing inspection thresholds, adding repeat inspection requirements for previously modified aircraft, and limiting interim repair lifespans. Amendment 2 further expands the scope to cover an additional location (BS 950) where new cracking reports emerged. The directive has evolved from a targeted response to specific reported cracks into a broader, ongoing airworthiness management program for aging Boeing 727 aircraft, with recommendations for permanent modifications to terminate the inspection cycle entirely."},"complexity_factors":["Multiple compliance pathways with 'whichever occurs last/later' conditional logic","Different inspection thresholds for different structural locations (BS 880/890/930/940 vs BS 950)","Three different inspection methods with different repeat intervals (visual/dye penetrant = 4000 flights, eddy current = 5000 flights)","Cross-reference to external US FAA directive (AD 92-19-11) and Boeing Service Bulletin for technical details","Nested timing requirements: initial inspection deadlines vs ongoing repeat inspection intervals vs terminating action","Technical aviation terminology requiring domain knowledge (body stations, eddy current, dye penetrant, blind rivets)"],"plain_english_summary":"This mandatory CASA airworthiness directive requires operators and maintenance engineers of Boeing 727s in Australia to inspect and repair the pressure floor in the main landing gear wheel well to prevent cabin depressurisation. Inspections (visual, dye‑penetrant or eddy‑current) must be performed at prescribed intervals and repeated until a permanent terminating modification is installed. The amendment expands inspected areas to include BS 950 after new cracking reports."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-107amdt-2-mlg-wheel-well-pressure-floor","history":"/api/acts/ad-b727-107amdt-2-mlg-wheel-well-pressure-floor/history","analysis":"/api/acts/ad-b727-107amdt-2-mlg-wheel-well-pressure-floor/analysis","conflicts":"/api/acts/ad-b727-107amdt-2-mlg-wheel-well-pressure-floor/conflicts","importantCases":"/api/acts/ad-b727-107amdt-2-mlg-wheel-well-pressure-floor/important-cases","documents":"/api/acts/ad-b727-107amdt-2-mlg-wheel-well-pressure-floor/documents"}}