COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Robinson R44 Series Helicopters
AD/R44/13 Rotor Drive Yoke 10/99 DM
Applicability: All Model R44 helicopters.
Requirement: 1. Determine, by inspection, if the yoke assembly, part number (P/N) C908-1C, from Lot No. 36B, 37, or 38 is installed.
Note 1: Yoke assemblies, P/N C908-1C, from Lot Nos. 36B, 37, and 38 were installed as original equipment in R44 helicopters, Serial Numbers 0219 and 0535 through 0608 (except numbers 0565, 0582, and 0592).
2. Replace any yoke assembly, P/N C908-1C, from Lot No. 36B, 37, or 38, with a serviceable yoke assembly from a lot other than 36B, 37, or 38 in accordance with the compliance procedure, steps 2 through 12, of Robinson Helicopter Company R44 Service Bulletin SB-35, dated July 26, 1999.
Note 2: Priority Letter FAA AD 99-17-17 refers.
Compliance: Before further flight after 25 August 1999, unless already accomplished.
This Airworthiness Directive becomes effective on 25 August 1999.
Background: The FAA received a report of an incident in which, during cruise flight, the pilot heard a loud bang and noticed no tail rotor effectiveness after entering autorotation. An investigation revealed that the yoke assembly P/N C908-1C, which connects the main rotor gearbox pinion shaft to the forward flexplate, had failed at a weld joint due to a crack. The cause of the crack is unknown, but still under investigation.
Robinson Helicopter Company has identified the manufacturing lots associated with the failed yoke. Failure of the yoke assembly could result in loss of main and tail rotor drive and subsequent loss of control of the helicopter.
Overview
The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, provide a comprehensive framework for ensuring the safety of civil aviation within Australia. Part 39 of these regulations specifically addresses airworthiness directives, which are critical in managing and mitigating risks associated with aircraft operation. One such directive, AD/R44/13, pertains to the Robinson R44 Series Helicopters and was introduced to address the specific problem of potential failure in the rotor drive yoke of certain helicopters. This directive was issued in response to an incident where a yoke assembly failed during flight, leading to a loss of tail rotor effectiveness. The policy objective of this directive is to enhance flight safety by ensuring that all affected helicopters are inspected and, if necessary, the problematic yoke assemblies are replaced to prevent future occurrences of such failures.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Model R44 helicopters, mandating strict compliance with the Airworthiness Directive AD/R44/13 concerning the rotor drive yoke. This legislation targets helicopter operators and owners who must ensure the safety and airworthiness of their aircraft by adhering to the outlined directives. The directive is applicable nationally and requires an inspection to determine if the yoke assembly, part number C908-1C, from specified lots (36B, 37, or 38) is installed. If such an assembly is found, it must be replaced with a yoke from a different lot in accordance with the compliance procedure detailed in Robinson Helicopter Company's Service Bulletin SB-35 dated July 26, 1999. This directive becomes effective from 25 August 1999, and compliance is mandatory before any further flight after this date, unless the required actions have already been taken. The directive's aim is to prevent potential catastrophic failures that could lead to loss of control of the helicopter, ensuring the safety of all personnel on board.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, include a schedule of airworthiness directives pertaining to Robinson R44 Series Helicopters. One such directive, AD/R44/13, concerns the rotor drive yoke. This directive applies to all Model R44 helicopters. The primary requirement (Section 1) is to inspect the yoke assembly, specifically part number (P/N) C908-1C from lot numbers 36B, 37, or 38, to determine if it is installed. These specific yoke assemblies were installed as original equipment in certain serial numbers of R44 helicopters. If any yoke assembly from these lots is found to be installed, it must be replaced with a serviceable yoke assembly from a different lot, as outlined in the compliance procedure steps 2 through 12 of Robinson Helicopter Company R44 Service Bulletin SB-35 dated July 26, 1999.
The obligations imposed by this directive (Section 2) are clear: helicopter owners and operators must ensure that the specified yoke assemblies are inspected and replaced if necessary. This directive requires adherence to the detailed steps provided in the aforementioned service bulletin. The compliance procedure must be completed before further flight after 25 August 1999, unless the inspection and replacement have already been accomplished. Failure to comply with this directive could compromise the safety and airworthiness of the helicopter, potentially leading to severe operational issues and safety risks.
Violating the requirements of this airworthiness directive (Section 3) can lead to serious consequences. Civil Aviation Regulations may impose penalties for non-compliance, and the operation of a non-compliant helicopter could result in significant safety risks, including potential loss of control during flight. The specific penalties for non-compliance are not detailed in the directive but could include fines, suspension of the helicopter's airworthiness certificate, or other regulatory actions. The maximum penalties would depend on the severity of the non-compliance and any additional breaches of civil aviation laws.