1AD/EC 135/5 Amdt 3 - Main Rotor Drive Torque Struts

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AIRWORTHINESS DIRECTIVE

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For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/EC 135/5 Amdt 2 and issues the following 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.

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Eurocopter EC 135 Series Helicopters

AD/EC 135/5

Amdt 3

Main Rotor Drive Torque Struts 10/2003 DM

Applicability: All Model EC135 helicopters.

Requirement: Action in accordance with Eurocopter Deutschland Alert Service Bulletin ECD 135- 63A-002 Revision 4.

Note 1: Installation of titanium torque struts constitutes terminating action for the Requirements of this Directive.

Note 2: LBA AD 2001-107/3 refers.

Compliance: 1. As of the effective date of this Directive, a life limit of 500 flight hours applies for aluminium torque struts.

2. Aluminium torque struts that have exceeded the 500 flight hour life limit at the effective date of this Directive, are to be replaced with new torque struts within 100 flight hours after 13 August 2003, unless already accomplished. If affected, during this 100 flight hour transition period aluminium torque struts are to be inspected daily before the first flight of the day.

3. Use of aluminium torque struts is permitted only until 31 December 2004.

If no externally mounted hoist is installed, and if the before the first flight of the day inspection is required to be performed by the pilot, this Directive shall be entered on the Maintenance Release as maintenance required. The required visual inspection may be performed and certified by the Pilot in Command who has been trained to do the inspection by an appropriately qualified person. In this case, a copy of the Requirement document and this Directive are to be carried in the aircraft.

This Amendment becomes effective on 13 August 2003.

Background: During flight a helicopter encountered a thump-like sound, which was later followed by unusual vibrations. After the subsequent precautionary landing, it was discovered that the attachment between the tensile stress-loaded torque strut located on the right hand side of the main transmission and the fuselage structure, had ruptured. This Directive requires a visual inspection for cracking and a change of installation side of the torque struts, and eventual strut replacement.