{"id":"F2006B05709","name":"AD/PA-31/121 Amdt 1 - Elevator Control System","slug":"ad-pa-31-121-amdt-1-elevator-control-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135508,"registerId":"commonwealth-F2006B05709-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/121 Amdt 1 - Elevator Control 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)  \nPiper PA-31 Series Aeroplanes\n\nAD/PA-31/121\n\nAmdt 1\n\n  \nElevator Control System 5/94 DM\n\nApplicability: Model PA31, PA31P, and PA31T series aircraft. Requirement: Accomplish the following inspections and procedures:\n\n    Gain access to the elevator controls in the tail by removing the bottom half of the tailcone and the fuselage side panels.\n\n    2. Remove the long pushrod that connects the bellcrank and the elevator horn.\n\n    3. Secure the aft end of the bungee link to the elevator horn with safety wire for removal and installation of the bungee attach bolt.\n\n    4. Inspect, using a magnetic particle procedure, the rod end shank and threads for cracks. If found cracked, replace the rod end with a part number 49261-02 or 452- 658 rod end.\n\n    5. Visually inspect the bearing in the rod end for wear and free movement. If wear is found or the bearing will not move, replace the rod end with a part number 49261- 02 or 452-658 rod end.\n\n    6. Inspect, using a 10x magnifying glass, the forward attach holes in the pushrod for cracks, corrosion, or elongation. If cracks, corrosion, or elongation is found, replace the pushrod with a part number 40847-00, 40847-04, or 40847-07 pushrod, as applicable.\n\n    7. Visually inspect the forward and aft attach area to ensure that both a forward bolt, part number 402 311 (AN174-12A), and an aft bolt, part number 402 317 (AN174- 11A), are installed. If either one of these bolts is not installed, install the applicable bolt or replace the existing bolt with one of the applicable part number.\n\n    8. Remove the safety wire, reinstall the pushrod, check to ensure that the elevator rigging is correct, and reinstall the bottom half of the tailcone and the fuselage side panels.\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.002.png)  \n\nNote 1: Figure 1 of this Directive illustrates the elevator assembly and the specific areas that are to be inspected.\n\nNote 2: FAA AD 93-24-02 Rev 1 Amdt 39-8810 refers.\n\nCompliance: Within 30 hours time in service after 9 March 1994.\n\nBackground: The FAA received a report of an incident where a Piper PA31T series aircraft experienced a complete loss of elevator control while in flight. An investigation disclosed that the aft control rod end bearing had separated into two pieces. Further investigation revealed a fatigue crack at the thread root, which extended through the rod end cross section.\n\nAmendment 1 is issued in response to a revision of the relevant FAA AD, which corrects the figure (contained in the AD) to reflect the correct installation, and provides an alternate rod end part number.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 1 does not change the applicability (still Model PA31, PA31P, PA31T) or the safety objective, but it modifies the instrument by correcting the installation figure and adding an alternate rod‑end part number, altering allowable replacement parts and clarifying the illustration (Amendment 1; Note 1; Note 2)."},"complexity_factors":["Technical inspection methods required (magnetic particle testing and 10× visual inspection) — requires specialised tooling/skills (Requirement steps 4 and 6).","Specific hardware and part‑number mandates (multiple part numbers listed for rod ends, pushrods and bolts) — enforces particular replacements (Requirement steps 4, 5, 6, 7).","Access and disassembly actions (removal of tailcone lower half and fuselage side panels; removal/reinstallation of pushrod and safety‑wiring) — increases labour/time (Requirement step 1, 2, 3, 8).","Short compliance window (within 30 hours time in service after 9 March 1994) — compresses scheduling for operators/maintenance providers (Compliance).","Clear cause and corrective focus (responds to an aft rod‑end fatigue failure and in‑flight loss of elevator control) — narrows scope to specific failure mode (Background).","Amendment is limited to a corrected figure and an alternate rod‑end part number — does not broaden applicability but changes allowable components (Amendment 1).","Cross‑reference to FAA AD (FAA AD 93‑24‑02 Rev 1 Amdt 39‑8810) — requires alignment with overseas directive and its illustration (Note 2).","Low regulatory discretion — prescriptive steps and pass/fail replacement criteria leave little administrative flexibility (Requirement steps 4–7)."],"plain_english_summary":"Requires operators and maintenance personnel of Piper PA‑31, PA31P and PA31T aeroplanes to open the tailcone, inspect the elevator control linkages with specified techniques (including magnetic‑particle and 10× visual inspection), and replace worn or cracked rod ends, bearings or pushrods using listed part numbers within 30 hours’ time in service. The rule responds to an in‑flight loss of elevator control and, in this amendment, corrects an installation figure and adds an alternate rod‑end part number."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose — preventing elevator control system failures in Piper PA-31 aircraft. Amendment 1 makes only minor technical corrections (fixing a figure and adding an alternate part number) without expanding the scope beyond the specific safety issue addressed in the original directive."},"complexity_factors":["Highly specific technical procedures requiring aviation maintenance expertise","Precise part number references (8 different part numbers specified)","Specific inspection methods mandated (magnetic particle procedure, 10x magnifying glass)","Conditional logic ('If found cracked...', 'If wear is found...')","Cross-reference to FAA AD 93-24-02 Rev 1 Amdt 39-8810","Time-based compliance deadline (30 hours time in service after specific date)"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Piper PA‑31 series aircraft to inspect and repair the elevator control system after an FAA investigation found a control‑rod metal‑fatigue failure that resulted in loss of elevator control. Inspections, replacement of cracked or worn components, and verification of correct bolt installation must be completed within 30 flight hours after 9 March 1994.\n\nAmendment 1 corrects a diagram error and adds an alternative approved replacement part number."},"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-121-amdt-1-elevator-control-system","history":"/api/acts/ad-pa-31-121-amdt-1-elevator-control-system/history","analysis":"/api/acts/ad-pa-31-121-amdt-1-elevator-control-system/analysis","conflicts":"/api/acts/ad-pa-31-121-amdt-1-elevator-control-system/conflicts","importantCases":"/api/acts/ad-pa-31-121-amdt-1-elevator-control-system/important-cases","documents":"/api/acts/ad-pa-31-121-amdt-1-elevator-control-system/documents"}}