{"id":"F2006B03401","name":"AD/B767/47 - Hydraulic Power Transfer Unit System","slug":"ad-b767-47-hydraulic-power-transfer-unit-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42942,"registerId":"commonwealth-F2006B03401-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B767/47 - Hydraulic Power Transfer Unit 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 767 Series Aeroplanes\n\nAD/B767/47 Hydraulic Power Transfer Unit System 12/90\n\nApplicability: All model B767-200 and B767-300 series aeroplanes on which Production Revision Record (PRR) B-11777 has not been incorporated.\n\nRequirement: 1. Aeroplanes identified in Boeing Alert Service Bulletin 767-29A0039, dated 11 May 1989, shall be modified in accordance with this Service Bulletin, and\n\n2. All other aeroplanes, in accordance with Boeing Alert Service Bulletin 767- 29A0039, Revision 1, dated 2 November 1989.\n\nNote: FAA AD 90-18-04 Amendment 39-6714 also refers.\n\nCompliance: Prior to 9 April 1992.\n\nBackground: Boeing has advised, analysis indicates that if both left and centre hydraulic systems of applicable aircraft become inoperative, and with adverse centre-of-gravity and gross weight combination, pitch control during approach and landing is marginal. The addition of the power transfer unit (PTU) system will provide stabiliser pitch control and additional landing flare capacity in the event of such a situation.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a narrow, specific purpose. It has not expanded beyond its original intent of mandating a specific hydraulic system modification for flight safety."},"complexity_factors":["Very short document (approximately 200 words)","Only 1 defined term (PTU - explained in background)","No cross-references to other legislation beyond a single note about a related FAA directive","Simple conditional structure: applicability based on single production revision status, with two alternative compliance paths","Single deadline with no exceptions or extensions mentioned","Technical content limited to referencing external Boeing service bulletins rather than prescribing detailed technical specifications"],"plain_english_summary":"This AD mandates fitting a Hydraulic Power Transfer Unit (PTU) on affected Boeing 767‑200/300s that weren’t already modified per Boeing’s production change, to restore stabiliser pitch control if both left and centre hydraulic systems fail. It addresses a discovered landing‑critical loss‑of‑control scenario and requires compliance via the specified Boeing Alert Service Bulletin by the stated compliance date, or the aircraft cannot meet the required safety standard."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope aligns with the AD’s stated safety fix: it targets B767-200/-300 aeroplanes lacking PRR B-11777 and requires a specified modification to mitigate marginal pitch control if left and centre hydraulic systems are lost (Applicability, Requirement, Background). There is no expansion beyond that technical population or remedy in the text."},"complexity_factors":["Narrow technical applicability: applies only to B767-200 and B767-300 aircraft that have not incorporated PRR B-11777 (Applicability).","Mandated technical modification: requires installation of a PTU following a specific Boeing Alert Service Bulletin (Requirement).","Multiple document references: two versions of the Boeing service bulletin are cited (Requirement) and an FAA AD is noted (Note), requiring cross-checking.","Fixed compliance deadline: a single calendar cut-off (9 April 1992) creates scheduling and parts/service capacity pressures for operators (Compliance).","Safety justification depends on a specific failure analysis (loss of left and centre hydraulic systems) and a stated performance benefit (Background), so verification relies on engineering assessment.","Operational/maintenance burden: modification is an airworthiness action with associated costs, downtime and required certified maintenance work (Requirement/Compliance)."],"plain_english_summary":"Mandates operators of Boeing 767-200/-300 aircraft without Production Revision Record B-11777 to install a power transfer unit (PTU) per Boeing Alert Service Bulletin 767-29A0039 (or Revision 1) by 9 April 1992. Boeing advised that loss of both left and centre hydraulic systems can leave pitch control marginal; the PTU restores stabiliser pitch control and increases landing flare capacity. Owners/operators must fund and schedule the modification under the Civil Aviation Safety Authority directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b767-47-hydraulic-power-transfer-unit-system","history":"/api/acts/ad-b767-47-hydraulic-power-transfer-unit-system/history","analysis":"/api/acts/ad-b767-47-hydraulic-power-transfer-unit-system/analysis","conflicts":"/api/acts/ad-b767-47-hydraulic-power-transfer-unit-system/conflicts","importantCases":"/api/acts/ad-b767-47-hydraulic-power-transfer-unit-system/important-cases","documents":"/api/acts/ad-b767-47-hydraulic-power-transfer-unit-system/documents"}}