AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AS 355/50 Amdt 3 and issues the following AD under subregulation 39.1 (1) of CAR 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.
Eurocopter AS 355 (Twin Ecureuil) Series Helicopters
AD/AS 355/50
Amdt 4
Tail Rotor Hub Pitch Change Bearings 13/2002
Applicability: AS 355 helicopters versions E, F, F1, F2, and N fitted with tail rotor hub pitch change plate, P/N’s 350A33-2004-00/-01/-02/-03/-05 and not incorporating Mod 076551 as detailed in Eurocopter AS 355 Service Bulletin No. 65.00.15R1.
Requirement: 1. Check the rotational torque of the tail rotor pitch change plate bearing in accordance with paragraph 2.B (1) of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3.
2. Carry out the axial play, friction point and brinelling check in accordance with paragraph 2.B (2) of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3.
3. Before installation of a spare pitch change plate assembly carry out the requirements of paragraphs 2.B 1 and 2.B 2 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3.
4. Disposition of components subject to the inspections as required by Items 1 - 3 of this Directive shall be in accordance with paragraph 2.B 3 of Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3.
Note 1: DGAC AD 1999-085-076(A) R3 refers.
Note 2: Incorporation of Eurocopter Service Bulletin AS 350 65.00.38.P5 constitutes terminating action for this Directive.
Compliance: 1. Unless previously accomplished; within 10 flying hours after 31 October 2002.
2. At intervals not to exceed 50 flying hours from the previous check (without exceeding 6 months between two checks).
3. Prior to installation of a tail rotor pitch change plate assembly or a tail rotor gearbox assembly.
4. During compliance with Requirements 1, 2, or 3, as applicable.
The compliance times of Amendment 3 of this Directive remain unchanged by this issue.
Eurocopter AS 355 (Twin Ecureuil) Series Helicopters
AS/AS 355/50 Amdt 4 (continued)
This Amendment becomes effective on 26 December 2002.
Background: In service reports have revealed deterioration of the tail rotor hub pitch change plate bearing may result in the seizure of the bearing and loss of control of the aircraft.
This Directive introduces measures to check for correct rotational torque, and regular maintenance checks to ensure the integrity of the assembly.
Amendment 1 was issued to correct Compliance Statement 2 to reflect the DGAC repetitive inspection requirements and to include the more stringent compliance requirements of DGAC 1999-084-057(A) R1 dated 14 May 1999.
Amendment 2 provides terminating action for this Directive and adds reference to disposition of components subject to the required inspections.
Amendment 2 of this Airworthiness Directive became effective on 15 June 2000. Amendment 3 was issued to reflect replacement of Eurocopter Service Bulletin No.
05.00.30 R2 with Eurocopter Alert Service Bulletin No. 05.00.30 Revision 3. The
Service Bulletin was upgraded to Alert status with no change to the technical content of the Service Bulletin.
Amendment 4 of this Airworthiness Directive has been issued to correct a typographical error in Amendment 3.
Amendment 3 of this Airworthiness Directive became effective on 31 October 2002. The original issue of this Airworthiness Directive became effective on 20 May 1999.
James Coyne
Delegate of the Civil Aviation Safety Authority 18 November 2002
The above AD is notified in the Commonwealth of Australia Gazette on 4 December 2002.
Overview
The Civil Aviation Safety Authority (CASA) issued Airworthiness Directive (AD) AD/AS 355/50 Amdt 4 to address an identified safety issue concerning the tail rotor hub pitch change bearings in Eurocopter AS 355 (Twin Ecureuil) Series Helicopters. This AD was enacted in response to reports of bearing deterioration, which could potentially lead to bearing seizure and loss of control of the aircraft. The AD was issued under the authority of the Civil Aviation Act 1988, with the aim of ensuring the ongoing airworthiness of aircraft operating in Australia. The directive mandates specific checks and maintenance procedures to ensure the safety of these aircraft, particularly focusing on the rotational torque and integrity of the tail rotor pitch change plate bearing. This regulatory action is essential for maintaining the high safety standards required in Australian aviation.
Scope and Application
The Airworthiness Directive (AD) AD/AS 355/50 Amdt 4 applies to Eurocopter AS 355 (Twin Ecureuil) Series Helicopters, specifically versions E, F, F1, F2, and N, that are fitted with a tail rotor hub pitch change plate bearing of certain part numbers and do not incorporate modification 076551 as detailed in Eurocopter AS 355 Service Bulletin No. 65.00.15R1. The directive is issued under the authority of the Civil Aviation Safety Authority (CASA) and is applicable across the Commonwealth of Australia. It mandates specific actions to address the identified unsafe condition, including the checking of rotational torque, axial play, friction point, and brinelling of the tail rotor hub pitch change plate bearing, with corresponding dispositions as per Eurocopter Alert Service Bulletin (ASB) No. 05.00.30 Revision 3. Compliance with these requirements must occur within specified timeframes, such as within 10 flying hours after 31 October 2002, at intervals not exceeding 50 flying hours or six months, and prior to the installation of certain assemblies. The directive also incorporates amendments that refine compliance requirements and clarify actions based on previous regulatory communications and service bulletins.
Key Provisions
This Airworthiness Directive (AD) mandates specific actions for certain Eurocopter AS 355 (Twin Ecureuil) series helicopters to address a safety concern related to the tail rotor hub pitch change bearings. The directive applies to AS 355 helicopters versions E, F, F1, F2, and N fitted with particular pitch change plates, excluding those that have incorporated modification 076551 as detailed in Eurocopter Service Bulletin No. 65.00.15R1. The directive outlines specific requirements for checking and maintaining these components to prevent potential bearing failures, which could lead to a loss of control of the aircraft. These requirements include checking the rotational torque of the tail rotor pitch change plate bearing, conducting axial play, friction point, and brinelling checks, ensuring specific checks are performed before installing a spare pitch change plate assembly, and disposing of components in accordance with certain guidelines.
Operators and owners of the affected helicopters must adhere to the specified compliance timelines and procedures. The initial check must be conducted within 10 flying hours after 31 October 2002 if not already performed. Subsequent checks must occur at intervals not exceeding 50 flying hours or six months, whichever is shorter. These checks must be performed before installing a tail rotor pitch change plate assembly or a tail rotor gearbox assembly. Additionally, any components found to be non-compliant with the directive's requirements must be disposed of in accordance with the specified guidelines.
Failure to comply with the requirements of this Airworthiness Directive may result in civil or criminal penalties. The exact consequences would depend on the specific nature and severity of the non-compliance. Non-compliance with airworthiness directives can lead to serious safety issues, including the potential for aircraft accidents. In the event of a breach, the Civil Aviation Safety Authority (CASA) may take enforcement actions, which could include fines, suspension or revocation of airworthiness certificates, and other regulatory actions. The penalties can vary, but in severe cases, they may include substantial financial penalties and potential criminal charges against individuals or corporations found to be in breach of the directive.