{"id":"F2006B02803","name":"AD/B737/1 Amdt 2 - Cockpit Side Window - F-N Window Post","slug":"ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42145,"registerId":"commonwealth-F2006B02803-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/1 Amdt 2 - Cockpit Side Window - F-N Window Post","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)  \nBoeing 737 Series Aeroplanes\n\nAD/B737/1\n\nAmdt 2\n\n  \nCockpit Side Window \\- “F-N” Window Post 7/95\n\nApplicability: Boeing 737 serial numbers 1 to 447.\n\nRequirement: Inspect visually, by eddy current and by X-ray, as applicable, the “F-N” window post in accordance with Boeing Service Bulletin (SB) 737-53-1023, Revision 11.\n\nNote: FAA AD 93-05-17 refers.\n\nCompliance: Inspect at the thresholds and intervals specified in Tables I and II of Boeing SB 737- 53-1023, Revision 11.\n\nBackground: One hundred and sixty two cracks have been experienced on 707, 727 and 737 aircraft in the subject region, including aircraft that have been modified and repaired to earlier issues of the SB. This SB has been identified by the B737 Ageing Aircraft Structures Working Group as a safety of flight item and requires the area to be modified; Directive AD/B737/40 refers. Amendment 1 extended the inspection area to structure above the cockpit window.\n\nAmendment 2 revises the Applicability.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"This is Amendment 2 to an existing directive originally issued in July 1995. The original directive required inspections of the F-N window post. Amendment 1 expanded the inspection area to include structure above the cockpit window. Amendment 2 (this version) revises the applicability — changing which specific aircraft serial numbers are covered. The scope has evolved through amendments but remains tightly focused on the single safety issue of cockpit window post cracking."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 1 defined term implicitly used ('F-N window post' — explained via reference to Boeing documentation)","Heavy reliance on external technical documents (Boeing Service Bulletin 737-53-1023, Revision 11) — the actual inspection procedures are not reproduced in the legislation","Simple conditional structure: if you operate these specific aircraft, you must do these specific inspections","Cross-reference to related Australian directive (AD/B737/40) and US FAA directive (93-05-17) for context","No nested exceptions or complex logical operators"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific inspections or repairs on aircraft.\n\n**What it does:**\nThis directive orders owners and operators of early-model **Boeing 737 aircraft** (serial numbers 1 to 447) to inspect a specific structural part called the **\"F-N\" window post** — a metal frame component next to the cockpit side windows.\n\n**Why it matters:**\nCracks have been found in this area on Boeing 707, 727, and 737 aircraft. These cracks are serious because they affect the structural integrity of the cockpit area. The directive requires three types of inspection:\n- **Visual inspection** (looking for visible cracks)\n- **Eddy current inspection** (using electromagnetic sensors to detect hidden cracks)\n- **X-ray inspection** (using radiography to see inside the metal)\n\n**Who must comply:**\nAnyone operating Boeing 737 aircraft with serial numbers 1 through 447 — essentially the oldest 737s in service.\n\n**What must be done:**\nOperators must follow the exact procedures in **Boeing Service Bulletin 737-53-1023, Revision 11**, including how often to inspect (the \"thresholds and intervals\" in Tables I and II).\n\n**Key context:**\n- This is **Amendment 2** — it updates an existing directive\n- The main change in this amendment: it revises which aircraft are covered (the \"Applicability\")\n- A related directive (AD/B737/40) requires permanent modification of this area, while this one requires ongoing inspections until that modification is done\n- The US Federal Aviation Administration has a matching rule (FAA AD 93-05-17)"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 2 revises the Applicability of the directive: it now applies to Boeing 737 serial numbers 1–447. Earlier amendments extended the inspection area above the cockpit window; Amendment 2 changes which airframes are covered but does not itself change the inspection methods or the SB referenced for intervals and procedures (Requirement; Compliance; Background)."},"complexity_factors":["Requires multiple specialised inspection methods (visual, eddy current, X‑ray) — technical skill and equipment needed.","Relies on an external document (Boeing SB 737‑53‑1023 Rev 11) for detailed procedures, thresholds and inspection intervals (dependency increases compliance complexity).","Mandated recurring inspections per Tables I and II in the SB — creates ongoing compliance burden and scheduling requirements.","Applicability covers a broad serial‑number range (1–447), requiring fleet‑level assessment by operators.","Cross‑references other directives (AD/B737/40) and FAA AD 93‑05‑17, creating coordination and potential overlapping obligations.","Amendment changes applicability, obliging operators to reassess which airframes fall within scope."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Boeing 737 aeroplanes (serial numbers 1–447) to inspect the cockpit “F‑N” window post using visual, eddy‑current and X‑ray methods in accordance with Boeing Service Bulletin 737‑53‑1023 Revision 11, at the thresholds and intervals given in that SB (Requirement; Compliance). It responds to repeated cracking in the region on 707/727/737 airframes and places inspection, repair and modification obligations and costs on affected operators (Background; AD/B737/40 reference)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post","history":"/api/acts/ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post/history","analysis":"/api/acts/ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post/analysis","conflicts":"/api/acts/ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post/conflicts","importantCases":"/api/acts/ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post/important-cases","documents":"/api/acts/ad-b737-1-amdt-2-cockpit-side-window-f-n-window-post/documents"}}