{"id":"F2006B02643","name":"AD/B727/121 - Takeoff Configuration Warning System","slug":"ad-b727-121-takeoff-configuration-warning-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41959,"registerId":"commonwealth-F2006B02643-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/121 - Takeoff Configuration Warning System","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 727 Series Aeroplanes\n\nAD/B727/121 Takeoff Configuration Warning System 9/90\n\nApplicability: All model Boeing 727 series aircraft not equipped with a system incorporating engine pressure ratio (EPR) logic for activation of the takeoff warning system.\n\nRequirement: 1. For 727 series aircraft with auto-speedbrakes operative: Modify the logic which enables the Takeoff Configuration Warning Systems (TOCWS) in accordance with Boeing Service Bulletin 727-31-29; 727-31-33; 727-31-35; or 727-31-36 as appropriate.\n\n    2. For 727 series aircraft not equipped with auto-speedbrakes or with the auto- speedbrakes deactivated:\n\n    Modify the logic which enables the Takeoff Configuration Warning System(TOCWS) in accordance with Boeing Service bulletin 727-31-29; 727- 31-33; 727-31-35; or 727-31-36 as appropriate; OR\n\n    b. Adjust the takeoff warning thrust lever actuated switches to operate at 19.5 degrees from the idle stop for takeoff configuration warning system arming in accordance with Boeing Service bulletin 727-31-30. Install a circuit breaker guard (cover) on the TOCWS circuit breaker, and safety wire the guard. Operation of the aircraft must be in accordance with the limitations of the TOCWS specified in Appendix 39 or 51 (as appropriate) of the aircraft Flight Manual.\n\nNote: FAA AD 90-03-18 refers.\n\nCompliance: Prior to 6 September 1992.\n\nBackground: Compliance with this AD is required in order to prevent takeoff configuration warning system nuisance warnings when taxi operations are conducted with the flaps intentionally retracted.","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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound airworthiness directive with a narrow, specific purpose: correcting a known technical fault in a particular aircraft system's logic. It has not expanded beyond its original safety intent."},"complexity_factors":["Short, single-purpose directive (approximately 250 words)","Only 4 defined technical terms (EPR, TOCWS, auto-speedbrakes, idle stop)","Simple conditional structure: two aircraft categories with distinct compliance paths","Clear cross-reference to FAA AD 90-03-18 for additional context","Specific Boeing Service Bulletin references provide unambiguous technical instructions","Single compliance deadline with no phased or graduated requirements"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of Boeing 727s lacking EPR-based takeoff-warning logic to modify the Takeoff Configuration Warning System to stop nuisance warnings during taxi. Depending on the aircraft’s speedbrake system, compliance involves either updated warning‑logic software or mechanical switch and circuit‑breaker safeguards. Work was required by 6 September 1992 to prevent alarm fatigue and ensure the warning only signals real takeoff hazards."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument itself does not state any change to its original scope. It prescribes mandatory modifications or adjustments for the identified fleet (727s without EPR logic) and sets a compliance deadline; no expansion or narrowing of applicability is indicated within the text."},"complexity_factors":["Applicability limited to Boeing 727 series aircraft lacking EPR logic (clear but narrowly targeted)","Two compliance pathways depending on auto-speedbrake status (Requirement 1 vs Requirement 2(a)/(b))","Multiple alternative Boeing Service Bulletins referenced (727-31-29; -31-33; -31-35; -31-36; -31-30) requiring correct selection","Technical specificity for the mechanical alternative (thrust-lever switches set to 19.5°) plus installation of circuit breaker guard and safety wiring","Operational constraint: must operate within TOCWS limitations in specified Flight Manual Appendices","Fixed compliance deadline (prior to 6 September 1992) creates scheduling and logistical pressure","Cross-reference to FAA AD 90-03-18 introduces potential for coordination or interpretation differences"],"plain_english_summary":"This Airworthiness Directive requires operators of Boeing 727 aircraft without an EPR-based takeoff warning system to either modify the takeoff-configuration warning logic using specified Boeing service bulletins, or (if auto-speedbrakes are absent or deactivated) adjust thrust-lever switches to 19.5° and fit a circuit-breaker guard with safety‑wiring, and comply with Flight Manual limitations. The Civil Aviation Safety Authority requires these changes to stop nuisance takeoff warnings during taxi. Operators pay for and arrange the work; compliance was required by 6 September 1992."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-121-takeoff-configuration-warning-system","history":"/api/acts/ad-b727-121-takeoff-configuration-warning-system/history","analysis":"/api/acts/ad-b727-121-takeoff-configuration-warning-system/analysis","conflicts":"/api/acts/ad-b727-121-takeoff-configuration-warning-system/conflicts","importantCases":"/api/acts/ad-b727-121-takeoff-configuration-warning-system/important-cases","documents":"/api/acts/ad-b727-121-takeoff-configuration-warning-system/documents"}}