{"id":"F2006B02949","name":"AD/B737/5 - Wing-To-Body Drag Angle","slug":"ad-b737-5-wing-to-body-drag-angle","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42291,"registerId":"commonwealth-F2006B02949-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B737/5 - Wing-To-Body Drag Angle","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 737 Series Aeroplanes\n\n \n\nAD/B737/5 Wing-To-Body Drag Angle 8/85\n\nApplicability: All model 737 aircraft, Line Numbers 1 to 316.\n\n \n\nRequirement: 1. FAA AD 85-03-06, Amendment 39-4998, up to and including Section C.\n\n \n\n2. Boeing SB 737-53-1031 Revision 3. Compliance: As detailed in Requirement Document No 1.\n\nBackground: There have been numerous reports of cracking in the wing-to-body drag angles.\n\nContinued operation with failed angles could lead to progressive cracking of adjacent structure and rapid decompression.\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\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":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument does not indicate any change of scope from its stated applicability. It applies to all model 737 aircraft, Line Numbers 1 to 316 (Applicability), and mandates compliance with FAA AD 85-03-06 up to Section C and Boeing SB 737-53-1031 Revision 3 (Requirement 1; Requirement 2). No alternate or expanded scope is provided in the text."},"complexity_factors":["References to external technical and regulatory documents (FAA AD 85-03-06 and Boeing SB 737-53-1031 Revision 3) which must be obtained and followed (Requirement 1; Requirement 2).","Safety-critical technical subject matter (wing-to-body drag angle cracking) requiring specialised inspection and repair procedures (Background).","Narrow applicability by aircraft line numbers (all model 737, Line Numbers 1 to 316) which requires operators to determine whether each airframe falls within scope (Applicability).","Compliance phrased by cross-reference (“As detailed in Requirement Document No 1”), increasing administrative steps to confirm exact obligations (Compliance).","Potential operational impacts (aircraft downtime, repair costs) implied but not quantified in the text, creating implementation planning complexity (Background; Compliance)."],"plain_english_summary":"This instrument requires owners and operators of Boeing 737s (Line Nos. 1–316) to carry out inspections and corrective action on wing-to-body drag angles following FAA AD 85-03-06 (up to Section C) and Boeing Service Bulletin 737-53-1031 Rev 3, with maintenance organisations obliged to perform work to those documents. It responds to reported cracking that could progress into adjacent structure and risk rapid decompression; operators bear the inspection, repair and downtime costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific structural defect in early-model Boeing 737 aircraft. It has not expanded beyond its original purpose of mandating inspection and repair of wing-to-body drag angle cracking."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined requirements, both referencing external documents rather than setting out detailed technical specifications","No nested conditional logic or exceptions within the directive itself","Simple applicability test (Line Numbers 1-316)","Single compliance pathway with no alternative methods of compliance (AMOCs) stated in this excerpt","No cross-references to other Australian legislation beyond the enabling Civil Aviation Regulations 1998"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of specific Boeing 737 aircraft to inspect and fix a structural problem in the \"wing-to-body drag angles\" — these are metal brackets or fittings where the wing connects to the fuselage (the main body of the plane).\n\n**Who it affects:**\nAll Boeing 737 aircraft with \"Line Numbers\" (manufacturing serial numbers) 1 through 316 — these are the earliest 737s built.\n\n**Why it matters:**\nThere have been multiple reports of **cracking** in these drag angles. If these brackets fail completely, it can cause:\n- Cracking to spread to nearby structure\n- **Rapid decompression** — a dangerous situation where the cabin suddenly loses pressure at altitude\n\n**What must be done:**\nOperators must follow two specific technical documents:\n- **FAA AD 85-03-06** (an American safety order, Section C) — the US Federal Aviation Administration had already identified this problem\n- **Boeing Service Bulletin 737-53-1031 Revision 3** — Boeing's official repair instructions\n\n**Compliance:**\nAircraft must be fixed according to the timeline and methods set out in the FAA document.\n\nThis is a **retroactive safety fix** — it applies to existing aircraft already in service, not just new ones."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b737-5-wing-to-body-drag-angle","history":"/api/acts/ad-b737-5-wing-to-body-drag-angle/history","analysis":"/api/acts/ad-b737-5-wing-to-body-drag-angle/analysis","conflicts":"/api/acts/ad-b737-5-wing-to-body-drag-angle/conflicts","importantCases":"/api/acts/ad-b737-5-wing-to-body-drag-angle/important-cases","documents":"/api/acts/ad-b737-5-wing-to-body-drag-angle/documents"}}