{"id":"F2006B02744","name":"AD/B727/43 - Automatic Pilot Servo Engage Switches - Modification","slug":"ad-b727-43-automatic-pilot-servo-engage-switches-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42086,"registerId":"commonwealth-F2006B02744-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B727/43 - Automatic Pilot Servo Engage Switches - Modification","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/B727/43 Automatic Pilot Servo Engage Switches - Modification\n\nApplicability: All models fitted with Sperry SP50 automatic pilots.\n\n# 6/67\n\n \n\nRequirement: 1. Modify the servo engage switches in accordance with Sperry SB TA-697-104.\n\n \n\n2. Aircraft which are fitted with unmodified automatic pilot control panels or which have accumulated 1500 hours time in service shall have the following placard fitted in clear view of the pilot:\n\n \n\n“The auto pilot must be turned off when operating below 3000 feet above ground level in a terminal area. Verify by the position of the control panel engage lever”.\n\n \n\nCompliance: For Para. 1 - Before 1 December 1967. For Para. 2 - Forthwith.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific technical issue with a specific aircraft system. It has not expanded beyond its original purpose of mandating a safety modification for autopilot engage switches."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 substantive requirements with clear conditional logic","Single defined applicability criterion (Sperry SP50 autopilot)","No cross-references to other legislation or complex definitions","Simple compliance dates (single fixed date and 'forthwith')","Straightforward trigger condition for placard requirement (unmodified panels OR 1500 hours)"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for **Boeing 727 aircraft** fitted with a specific type of automatic pilot system (Sperry SP50).\n\n**What it does:**\n- **Requires a hardware fix**: Airlines must modify the servo engage switches (the controls that activate the autopilot's servo motors) following a specific manufacturer's service bulletin (Sperry SB TA-697-104).\n- **Requires a warning placard**: If the aircraft hasn't had the modification done OR has flown 1,500 hours, a visible warning must be placed in the cockpit stating: *\"The auto pilot must be turned off when operating below 3,000 feet above ground level in a terminal area. Verify by the position of the control panel engage lever.\"*\n\n**Who it affects:**\n- Operators of Boeing 727s with Sperry SP50 autopilot systems\n- Maintenance engineers responsible for implementing the modification\n\n**Why it matters:**\nThis directive addresses a safety risk where the autopilot could potentially remain engaged at low altitudes near airports (below 3,000 feet), which could interfere with manual control during critical phases of flight like takeoff and landing. The modification and placard ensure pilots are aware of the limitation and can manually verify autopilot disengagement."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive expressly applies to all Boeing 727s fitted with Sperry SP50 automatic pilots and prescribes either modification per the Sperry service bulletin or an interim placard; the text contains no indication that the scope was altered from what it states."},"complexity_factors":["Narrow technical applicability: applies only to Boeing 727 aircraft fitted with Sperry SP50 automatic pilots (simplifies population determination).","Dependency on an external technical document: requires compliance with Sperry SB TA-697-104 (operators must obtain and follow that service bulletin).","Dual compliance mechanism and timing: mandatory modification by a set date versus immediate interim placard requirement (creates scheduling and interim‑operation distinction).","Time‑in‑service threshold: placard requirement also applies to aircraft with 1,500 hours TIS, requiring operators to track and verify hours.","Operational specification: placard must be placed 'in clear view of the pilot' with exact text provided (small but specific human‑factor requirement).","Short/urgent compliance window (administrative burden to schedule maintenance promptly)."],"plain_english_summary":"Requires modification of the autopilot servo‑engage switches on Boeing 727s fitted with Sperry SP50 autopilots to the specification in Sperry SB TA‑697‑104, and—until modification—requires a cockpit placard directing pilots to turn the autopilot off below 3,000 feet AGL in terminal areas. Affects all operators of those 727s; it matters because operators must carry out the specified hardware change by the deadline or immediately fit and monitor the placard, creating maintenance, record‑keeping and operational checks."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b727-43-automatic-pilot-servo-engage-switches-modification","history":"/api/acts/ad-b727-43-automatic-pilot-servo-engage-switches-modification/history","analysis":"/api/acts/ad-b727-43-automatic-pilot-servo-engage-switches-modification/analysis","conflicts":"/api/acts/ad-b727-43-automatic-pilot-servo-engage-switches-modification/conflicts","importantCases":"/api/acts/ad-b727-43-automatic-pilot-servo-engage-switches-modification/important-cases","documents":"/api/acts/ad-b727-43-automatic-pilot-servo-engage-switches-modification/documents"}}