AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Robinson R44 Series Helicopters
AD/R44/19 Main Rotor Clutch Drive Shafts 1/2004
DM
Applicability: R44 helicopters that have had the main rotor part number (P/N) C166 clutch drive shaft disconnected from the P/N C907 yoke since assembly by the Robinson Helicopter Company, regardless of the reason for disconnecting the C166 clutch shaft.
Requirement: Requirement 1:
Disassemble the main rotor C907 yoke to C166 clutch shaft joint and:
- Inspect the C907 yoke to C166 clutch shaft joint for evidence of major fretting in the yoke to shaft joint bolt holes. For the purpose of this directive, major fretting is defined as any evidence of the machining marks in any of the bolt holes being partly or fully obliterated. Remove from service C907 yokes and C166 shafts exhibiting evidence of major fretting in any hole, before further flight.
b. Inspect the C907 yoke to C166 clutch shaft joint assembly bolts for evidence of fretting. Remove from service any C907 yoke to C166 clutch shaft joint assembly bolt exhibiting evidence of fretting, before further flight.
c. Inspect the C166 clutch shaft for evidence of cracking in the area of the yoke to shaft joint bolt holes. Remove from service C166 clutch shafts exhibiting evidence of cracking, before further flight.
d. Inspect the C907 yoke for evidence of paint in the area where the yoke to clutch shaft joint block plates contact the yoke. Remove any evidence of paint in the area where the yoke to clutch shaft joint block plates contact the yoke, before further flight.
e. Inspect the C907 yoke to C166 clutch shaft joint for evidence of a non Robinson Helicopter Company approved jointing compound in the mating surfaces. Remove all evidence of an unapproved jointing compound in the mating surfaces, before further flight.
Note: The Robinson Helicopter Company does not approve the use of a jointing compound such as Mastinox or Duralac during the assembly of the clutch drive shaft.
Robinson R44 Series Helicopters
AD/R44/19 (continued)
Requirement 2:
- In accordance with a magnetic particle inspection (MPI) procedure approved either by the Robinson Helicopter Company or a Civil Aviation Regulation (1988) CAR 2A(4) delegate; carry out a MPI of C907 yokes removed from service in accordance with Requirement 1 of this directive.
b. In accordance with a MPI procedure approved by the Robinson Helicopter Company or a CAR (1988) 2A(4) delegate; carry out a MPI of C166 clutch shafts removed from service in accordance with Requirement 1 of this directive.
Compliance: 1. Unless previously accomplished; within 10 hours time in service from the effective date of this directive.
2. Before installation in a helicopter.
This Airworthiness Directive becomes effective on 3 December 2003.
Background: Airworthiness Directive AD/R22/51 was issued 12 November 2003 in response to the preliminary findings of the investigation of a fatal R22 accident. That investigation has disclosed evidence of fatigue in a fractured main rotor clutch drive shaft. The failed shaft had been assembled with the yoke painted in the area of the yoke to shaft assembly bolts and a non-approved jointing compound was found in the area of the joint mating surfaces. A combination of the two discrepancies probably resulted in a loss of assembly torque and movement of the joint in service.
This directive has been issued to address R44 helicopter clutch shafts that may have been installed using maintenance practices similar to those that contributed to a fatal R22 accident.
Neville Probert
Delegate of the Civil Aviation Safety Authority 28 November 2003
The above AD is notified in the Commonwealth of Australia Gazette on 3 December 2003.
Overview
The Airworthiness Directive (AD) AD/R44/19 was issued by the Civil Aviation Safety Authority (CASA) in 2003 to address safety concerns associated with the Robinson R44 series helicopters, specifically relating to the main rotor clutch drive shafts. The AD was enacted under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 (CASR 1998) and was prompted by preliminary findings of a fatal accident involving the R22 helicopter model, which indicated fatigue in a fractured main rotor clutch drive shaft. The policy objective of this directive is to prevent similar incidents by ensuring that any R44 helicopters with specified main rotor parts undergo necessary inspections and repairs to correct unsafe conditions. This directive applies to all R44 helicopters that have had the main rotor part number (P/N) C166 clutch drive shaft disconnected from the P/N C907 yoke since assembly, irrespective of the reason for the disconnection.
Scope and Application
The Airworthiness Directive (AD) AD/R44/19 pertains to Robinson R44 Series Helicopters that have had the main rotor part number (P/N) C166 clutch drive shaft disconnected from the P/N C907 yoke since their assembly by the Robinson Helicopter Company, irrespective of the reason for such disconnection. This AD applies to all such helicopters, regardless of their geographical location within Australia. The AD is issued under the Civil Aviation Safety Regulations 1998 (CASR) by a delegate of the Civil Aviation Safety Authority (CASA) and is intended to address potential safety issues identified in the main rotor clutch drive shafts of the mentioned helicopters. The directive mandates specific actions to be taken in relation to the inspection and maintenance of the main rotor components, ensuring that any identified issues are rectified to maintain the airworthiness of the helicopters. The AD also includes a compliance timeline, requiring that the specified actions be completed within 10 hours of time in service from the effective date of the directive and before the helicopter is installed in service. The directive is applicable to all helicopters fitting the described criteria and does not specify any exclusions or exemptions within the provided text.
Key Provisions
The Airworthiness Directive AD/R44/19 issued by the Civil Aviation Safety Authority (CASA) under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998, requires specific actions to be taken in relation to Robinson R44 Series Helicopters to address safety concerns identified in the main rotor clutch drive shaft. Section 1 of the AD applies to all R44 helicopters where the main rotor part number (P/N) C166 clutch drive shaft has been disconnected from the P/N C907 yoke since assembly by the Robinson Helicopter Company. The directive mandates inspections and corrective actions to ensure the safety of these components, including the removal from service of any parts exhibiting signs of major fretting, cracking, or improper assembly practices.
The obligations under this directive are clear and detailed. Operators of affected helicopters must disassemble the main rotor C907 yoke to C166 clutch shaft joint to inspect for evidence of major fretting in the yoke to shaft joint bolt holes, fretting in the assembly bolts, and cracking in the clutch shaft. Any yokes or shafts exhibiting these issues must be removed from service before further flight. Additionally, any evidence of paint in the yoke area where the yoke to clutch shaft joint block plates contact the yoke must be removed, as must any non-approved jointing compound in the mating surfaces. The directive also requires magnetic particle inspections (MPI) of removed yokes and shafts according to approved procedures.
Failure to comply with the requirements of this Airworthiness Directive may result in serious safety issues, potentially leading to aircraft accidents. The AD outlines specific penalties and consequences for non-compliance, although the exact penalties are not specified within the text of this directive. Generally, non-compliance with CASA directives can lead to enforcement actions, fines, or other civil or criminal penalties under the Civil Aviation Act 1988. In the most severe cases, non-compliance could result in the grounding of the aircraft, which could have significant operational and financial impacts for the operators.
In summary, Airworthiness Directive AD/R44/19 mandates detailed inspections and corrective actions on Robinson R44 Series Helicopters to ensure the safety of the main rotor clutch drive shaft. Operators must adhere to these requirements to prevent potential safety issues, with potential consequences including fines, enforcement actions, or grounding of the aircraft if the directive is not followed.