{"id":"F2006B03413","name":"AD/B767/6 - Flying Controls Self Locking Nuts","slug":"ad-b767-6-flying-controls-self-locking-nuts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42954,"registerId":"commonwealth-F2006B03413-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B767/6 - Flying Controls Self Locking Nuts","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 767 Series Aeroplanes\n\nAD/B767/6 Flying Controls Self Locking Nuts 12/85\n\nTX\n\nApplicability: All Model 767 with line position 2 to 121, and 124 to 126\\. Requirement: Action in accordance with:\n\n    Boeing Alert Service Bulletin 767-27A0064.\n\n    2. (FAA ADT85-21-51 Paras. A and B refer). Compliance: As detailed in Requirement Document No. 2.\n\nBackground: The manufacturer has advised that two incidents of defective self-locking nuts found in the primary flight control system (horizontal stabilizer) have been reported. The same type of nut is also used in the secondary flight control system \\- trailing edge flap and spoiler.\n\nThese reports indicate that the self-locking nuts have backed off which could cause the disconnection of actuators from control surfaces and result in complete or partial loss of control of the aircraft.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"The AD applies to the specified subset of Boeing 767 aeroplanes and directs action to address defective self‑locking nuts in flight control systems. The text contains no indication that the scope was broadened or narrowed from the original technical problem; it targets the airframes (line positions 2–121, 124–126) and the identified hardware (self‑locking nuts) as described in the Background and Applicability sections."},"complexity_factors":["Cross-references to multiple external technical documents (Boeing Alert Service Bulletin 767-27A0064; FAA ADT85-21-51; Requirement Document No. 2) — procedural detail is not in the AD itself","Applicability limited to specified line positions (2–121, 124–126), requiring operators to check serial/line position records","Safety-critical subject matter (flight control hardware) raises operational and regulatory stakes","Enforcement and compliance depend on interpreting and implementing external service instructions","Potential for operational disruption (aircraft downtime) and parts/labour costs for affected operators"],"plain_english_summary":"This airworthiness directive from CASA requires operators of specified Boeing 767s (line positions 2–121 and 124–126) to carry out inspections and corrective actions for certain self‑locking nuts in flight‑control systems, following Boeing Alert Service Bulletin 767-27A0064, FAA ADT85‑21‑51 and the referenced Requirement Document No. 2. It responds to reports of nuts backing off that could disconnect actuators and cause partial or total loss of control; operators bear costs and must obtain the external technical documents to comply."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific aircraft serial numbers. It has not expanded beyond its original purpose of mandating inspection/replacement of defective self-locking nuts."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined applicability criteria (line position ranges)","Single cross-reference to Boeing Service Bulletin and FAA AD","No nested exceptions or conditional logic","Straightforward command structure: identify aircraft → apply bulletin → comply by date","No interpretation section with defined terms"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it as a \"recall notice\" for aircraft, but legally binding.\n\n**What it does:** It requires owners and operators of specific Boeing 767 aeroplanes to inspect and fix a dangerous problem with self-locking nuts in the flight control systems.\n\n**Who it affects:** All Boeing 767 aircraft with serial numbers (\"line positions\") 2 through 121, and 124 through 126.\n\n**The safety problem:** The manufacturer reported two incidents where nuts in the primary flight control system (the horizontal stabilizer — the part that controls the plane's pitch) came loose. These same nuts are also used in secondary controls (flaps and spoilers). If these nuts back off completely, the actuators (the mechanisms that move the control surfaces) could disconnect, causing partial or complete loss of aircraft control.\n\n**What must be done:** Operators must follow the instructions in **Boeing Alert Service Bulletin 767-27A0064** and the referenced **FAA AD 85-21-51** (sections A and B). Compliance timing is set out in \"Requirement Document No. 2\" (not fully detailed here).\n\n**Why it matters:** This is a critical safety issue. Loose nuts in flight controls can lead to catastrophic loss of control. The directive makes the fix mandatory — operators cannot legally fly these aircraft until they comply."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b767-6-flying-controls-self-locking-nuts","history":"/api/acts/ad-b767-6-flying-controls-self-locking-nuts/history","analysis":"/api/acts/ad-b767-6-flying-controls-self-locking-nuts/analysis","conflicts":"/api/acts/ad-b767-6-flying-controls-self-locking-nuts/conflicts","importantCases":"/api/acts/ad-b767-6-flying-controls-self-locking-nuts/important-cases","documents":"/api/acts/ad-b767-6-flying-controls-self-locking-nuts/documents"}}