{"id":"F2006B10579","name":"AD/HU 269/103 - Lower Coupling Drive Shaft","slug":"ad-hu-269-103-lower-coupling-drive-shaft","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":116421,"registerId":"commonwealth-F2006B10579-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/HU 269/103 - Lower Coupling Drive Shaft","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)  \nSchweizer (Hughes) 269 Series Helicopters\n\nAD/HU 269/103 Lower Coupling Drive Shaft 1/94\n\nApplicability: Model 269A, TH55A, 269A-1, 269B and 269C helicopters.\n\nNote: Model 269C helicopters S/N 1628 and subsequent were delivered from the factory with Part I of the Requirement document incorporated.\n\nRequirement: Unless previously carried out action in accordance with Schweizer SB B-257-1.\n\nNote: FAA AD 93-17-13 Amdt 39-8684 refers.\n\nCompliance: Within 100 hours time in service from 15 January 1994 or by 15 April 1994, whichever occurs first. Thereafter, at intervals not exceeding 300 hours time in service reinspect the drive shaft for cracking in accordance with Part I of the requirement document.\n\nBackground: Damage has occurred to the lower coupling drive shaft due to engine overspeed during start up.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1710},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope addressing a specific safety defect (lower coupling drive shaft damage from engine overspeed) in the Schweizer 269 helicopter series. No evidence of expanded regulatory reach, additional aircraft models, or supplementary requirements beyond the initial airworthiness correction."},"complexity_factors":["Single, clearly defined mechanical issue with straightforward remedy","Limited applicability to specific helicopter models only","References external technical standard (Schweizer Service Bulletin B-257-1) rather than embedding complex technical specifications","Simple compliance structure with one initial deadline and one recurring interval","Single exemption clause for specific factory-delivered serial numbers"],"plain_english_summary":"**What this does:** This is a mandatory safety order (an Airworthiness Directive) requiring owners and operators of specific Schweizer (Hughes) 269 series helicopters to inspect and potentially replace the lower coupling drive shaft.\n\n**Who it affects:** Owners and operators of Model 269A, TH55A, 269A-1, 269B, and 269C helicopters. If you have a Model 269C with serial number 1628 or higher, you're already compliant because the factory installed the fix before delivery.\n\n**What you must do:**\n* **Initial inspection:** Check the drive shaft for damage and carry out any required replacement according to the manufacturer's Service Bulletin B-257-1. You must complete this by **whichever comes first**: 15 April 1994, or within 100 hours of flight time after 15 January 1994.\n* **Ongoing checks:** After the initial inspection, you must re-inspect the drive shaft for cracks every 300 hours of flight time.\n\n**Why it matters:** Engine overspeed during startup has been damaging these drive shafts. If a cracked shaft fails in flight, the helicopter could lose rotor power or control."},"summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"The instrument is an original airworthiness directive; no amendments are indicated."},"complexity_factors":["Narrow technical scope limited to a single aircraft component","Prescribes a straightforward recurring inspection schedule","No legal interpretation or policy change"],"plain_english_summary":"This AD requires mandatory inspections of the lower coupling drive shaft on certain Schweizer (Hughes) 269 series helicopters to detect cracking caused by engine overspeed during start‑up. Affected owners, operators and maintenance providers must perform initial and recurring inspections (or comply if already done per Schweizer Service Bulletin B‑257‑1). It mirrors the FAA AD and is intended to prevent in‑flight failure."}},"importantCases":[],"_links":{"self":"/api/acts/ad-hu-269-103-lower-coupling-drive-shaft","history":"/api/acts/ad-hu-269-103-lower-coupling-drive-shaft/history","analysis":"/api/acts/ad-hu-269-103-lower-coupling-drive-shaft/analysis","conflicts":"/api/acts/ad-hu-269-103-lower-coupling-drive-shaft/conflicts","importantCases":"/api/acts/ad-hu-269-103-lower-coupling-drive-shaft/important-cases","documents":"/api/acts/ad-hu-269-103-lower-coupling-drive-shaft/documents"}}