AD/EC 135/16 Rotor Control Bearing Attachment (Cth)

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 39.001(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.

Eurocopter EC 135 Series Helicopters

AD/EC 135/16 Rotor Control Bearing Attachment 8/2008 DM

Applicability:

EUROCOPTER Deutschland helicopter - EC135 and EC635 - all models.

Requirement:

1.    Inspect the bearings for correct attachment, in accordance with EUROCOPTER Alert Service Bulletin (ASB) EC135-67A-019 dated 28 April 2008 or later NAA approved revision.

2.    If incorrectly-fixed bearings are found during the inspection per Requirement 1 of this Airworthiness Directive (AD), re-bond bearings or replace the control levers in accordance with ASB EC135-67A-019 or later NAA approved revision.

Note:  German LBA AD D-2008-178 dated May 2008 refers.

Compliance:

Within the next 50 flight hours after the effective date of this AD, but not later than 30 June 2008; and

Repetitively inspect thereafter at each periodic inspection or annual inspection, whichever comes first.

This Airworthiness Directive becomes effective on 30 May 2008.

Background:

During accomplishment of an inspection on a MBB BK117 C-2, bearings were detected which had not been correctly fixed.  Bearings fixed incorrectly may cause the respective lever to shift in the axial direction.  Under unfavourable circumstances, the lever might get into contact with the helicopter structure and thus impair the controls freedom of movement.  As some bearings of the EC135 are fixed with the same procedure, they could be affected by the same production discrepancy.

The actions specified by this AD are intended to prevent impairment of the controls freedom of movement by incorrectly fixed bearings which can result in reduced controllability of the helicopter.

David Villiers
Delegate of the Civil Aviation Safety Authority

29 May 2008