Federal Register of Legislation - Australian Government

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AD/ARRIEL/24 Amdt 1 Airworthiness Directives/Pt 106 — Engines as made
Constant Delta Pressure Valve Diaphragm
Administered by: Infrastructure and Transport
Exempt from sunsetting by the Legislative Instruments Act 2003 s 54(2) item 9
Registered 07 Aug 2007
Tabling HistoryDate
Tabled HR08-Aug-2007
Tabled Senate09-Aug-2007
Date of repeal 02 Jul 2009
Repealed by AD/ARRIEL/24 Amdt 2 - Constant Delta Pressure Valve Diaphragm

 

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/ARRIEL/24 and issues the following 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.

Turbomeca Turbine Engines - Arriel Series

AD/ARRIEL/24 Amdt 1

Constant Delta Pressure Valve Diaphragm

9/2007

 

Applicability:

Turbomeca ARRIEL 2B1 turboshaft engines.

Note 1:  These engines are known to be installed on, but not limited to, Eurocopter (formerly Aérospatiale) AS 350 B3 and EC 130 B4 helicopters.

Requirement:

Replace the constant delta P diaphragm in accordance with Turbomeca Mandatory Service Bulletin No. A292 73 2818, Revision 1 or later DGAC approved revision.

Note 2:  EASA AD 2007-0126 dated 7 May 2007 refers.  This AD supersedes EASA AD 2007-0006.

Compliance:

For any Hydro Mechanical Unit (HMU) that has operated more than 1500 flight hours since new, overhaul, incorporation of SB 292 73 2105 (all issues), or incorporation of SB 292 73 2818 (all issues), no later than 30 September 2007.

After 30 September 2007, upon accumulating 1500 flight hours since new, overhaul, incorporation of SB 292 73 2105 (all issues), or incorporation of SB 292 73 2818 (all issues).

 

This Amendment becomes effective on 30 August 2007.

Background:

This AD is prompted by several reported cases of rupture of the constant delta pressure valve diaphragm on ARRIEL 2B1 engines, due to the wear of the delta-P diaphragm fabric.  Rupture can result in the loss of the automatic control mode of the helicopter, accompanied with a deterioration of the behaviour of the auxiliary back-up mode (emergency mode).  In order to reduce the probability of a diaphragm rupture, this AD requires the removal from service of all the delta Pressure valve diaphragms logging more than 1,500 hours since new.

The original issue of this AD required the replacement of parts at 2,000 flight hours. A review of the return parts has prompted a reduction of the interval down to 1,500 flight hours to further reduce the possibility of delta-P rupture.

 

 

 

 

The original issue of this AD became effective on 23 January 2007.


David Punshon
Delegate of the Civil Aviation Safety Authority

26 June 2007