AD/AB139/7 Tail Boom Assembly (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.

Agusta AB139 and AW139 Series Helicopters

AD/AB139/7		Tail Boom Assembly	10/2008 DM
Applicability:	AB139 and AW139 helicopters, all serial numbers, if a tail boom assembly Part Number (P/N) 3G5350A00131, P/N 3G5350A00132, P/N 3G5350A00133 or P/N 3G5350A00134 is installed.
Requirement:	Action in accordance with EASA AD 2008-0157. Note:  Agusta Bollettino Tecnico (BT) 139-134 refers.
Compliance:	Required as indicated in the requirement document. Note:  Report all defects to CASA (via SDR) and the type certificate holder.
This Airworthiness Directive becomes effective on 27 August 2008.
Background:	Some operators of AB/AW139 helicopters have reported finding debonding of fuselage tail boom panels.  This condition, if not detected and corrected, could lead to the structural collapse of the tail boom installation, resulting in loss of control of the helicopter. This directive requires repetitive inspections of the tail boom assembly and the reporting of defects to CASA and the type certificate holder.

David Villiers
Delegate of the Civil Aviation Safety Authority

15 August 2008