COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Schweizer (Hughes) 269 Series Helicopters
AD/HU 269/106 Main Transmission Pinion Assembly and Ring Gear
2/98
Applicability: All model 269A, 269A-1, 269B, 269C and TH-55A helicopters incorporating main rotor transmissions containing the following pinion assemblies and ring gears, which are installed individually or as a set.
P/N 269A5103-31 or -41 pinion assembly identified by the letters EGR, ACR or the manufacturer code number 23751 (EGR) or 57152 (ACR).
P/N 269A5104-5 ring gear identified by the letters EGR, ACR or the manufacturer code number 23751 (EGR) or 57152 (ACR).
Requirement: Unless previously carried out, inspect the pinion and ring gear teeth in accordance with Schweizer Service Bulletin B-244.2 dated 19 February 1996. Pinion assemblies and ring gears removed from service as a result of this directive shall be permanently retired from service.
Note: FAA AD 97-23-06 Amdt 39-10194 refers.
Compliance: Before further flight from the effective date should a clicking or tapping sound or other unusual noise or vibration be noted while operating the helicopter or, if a metal particle is found on the magnetic drain plug during routine maintenance.
Within the next 50 hours time in service from the effective date. Thereafter, re inspect at intervals not exceeding 50 hours time in service until ring gear P/N 269A5104-5 has been replaced with ring gear P/N 269A5104-7, S/N S2100 or higher.
Note Installation of the P/N 269A5104-7 ring gear with S/N S2100 or higher provides terminating action for this directive.
This airworthiness directive becomes effective on 29 January 1998.
Background: Failure of a gear tooth from the main rotor transmission ring gear have been reported.
Overview
The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, establish the regulatory framework for civil aviation within Australia. This legislation aims to ensure the safety and efficiency of civil aviation operations. The Civil Aviation Regulations 1998 were introduced to address the need for comprehensive safety standards and regulations governing all aspects of civil aviation in Australia. One part of these regulations is the Schedule of Airworthiness Directives, which includes directives such as AD/HU 269/106, aimed at ensuring the continued airworthiness of specific aircraft types. The policy objective of these regulations is to maintain the highest standards of safety in the Australian civil aviation industry, protecting both the public and aviation personnel.
The specific airworthiness directive AD/HU 269/106 pertains to Schweizer (Hughes) 269 Series Helicopters, requiring inspections of the main transmission pinion assembly and ring gear to address reported failures in the gear teeth of the main rotor transmission. This directive ensures that affected helicopters are inspected and maintained to prevent potential in-flight failures, thereby enhancing aviation safety. The directive became effective on 29 January 1998, requiring compliance by operators of the specified helicopter models.
Scope and Application
The Civil Aviation Regulations 1998, specifically under Part 39, imposes stringent airworthiness directives that apply to all Schweizer (Hughes) 269 Series Helicopters, including models 269A, 269A-1, 269B, 269C, and TH-55A, if they contain certain identified main rotor transmission pinion assemblies and ring gears. This directive mandates inspections to ensure safety, particularly focusing on the prevention of gear tooth failure which has been reported in the past. The requirement applies to helicopters with specific part numbers and serial numbers of the pinion assemblies and ring gears, necessitating a thorough inspection procedure as outlined in Schweizer Service Bulletin B-244.2. Non-compliant parts must be retired from service permanently. Compliance with these directives is critical, with immediate action needed if unusual sounds or vibrations are detected during operation or if metal particles are found during maintenance. The directive becomes effective from 29 January 1998, and inspections must be carried out within the first 50 hours of operation post-directive, with subsequent inspections occurring at intervals not exceeding 50 hours until the specified ring gear replacement is made.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 105, includes an airworthiness directive (AD) concerning Schweizer (Hughes) 269 Series helicopters (AD/HU 269/106). This directive pertains to the main transmission pinion assembly and ring gear, particularly for models 269A, 269A-1, 269B, 269C, and TH-55A helicopters equipped with certain pinion assemblies and ring gears (section 2). The directive mandates an inspection of the pinion and ring gear teeth in accordance with Schweizer Service Bulletin B-244.2 dated 19 February 1996 (section 3). Any pinion assemblies or ring gears removed from service as a result of this directive must be permanently retired from service (section 3).
This AD imposes several obligations on the operators of affected helicopters. Firstly, operators must ensure that a specific inspection is carried out unless it has already been performed. The inspection must be conducted before further flight if a clicking or tapping sound or other unusual noise or vibration is detected during operation, or if metal particles are found on the magnetic drain plug during routine maintenance (section 4). Secondly, the inspection must be completed within the next 50 hours of service from the directive's effective date and then at intervals not exceeding 50 hours of service until the specified ring gear is replaced (section 4). The directive also references FAA AD 97-23-06 Amdt 39-10194, which provides additional context and guidance.
The directive outlines serious consequences for non-compliance. Failure to adhere to the requirements set forth in this airworthiness directive may result in operational hazards, potentially leading to gear tooth failure in the main rotor transmission. The directive became effective on 29 January 1998, and operators are expected to comply with the specified inspection and replacement intervals to ensure continued airworthiness and safety of the aircraft (section 2). The directive underscores the importance of timely inspections and the replacement of specified components to mitigate risks associated with gear tooth failure.