AD/Arrius/16 Amdt 1 Engine Fuel and Control P3 Air Pipe (Cth)

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/ARRIUS/16 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 - Arrius Series

AD/ARRIUS/16 Amdt 1 Engine Fuel and Control - P3 Air Pipe 4/2009

Applicability:

TURBOMÉCA ARRIUS 2F turbo-shaft engines.

Note 1:  These engines are installed in, but not limited to Eurocopter EC120B helicopters.

Requirement:

1.    Carry out the following instructions in accordance with Turbomeca Mandatory Service Bulletin N° 319 75 4810 or later approved revision:

a.     Visually inspect P3 air pipe (first section) and right hand (RH) rear half-wall.

b.    Inspect play between P3 air pipe (first section) and RH rear half-wall.

c.     Replace P3 air pipe (first section) if any damage is found.

d.    Re-adjust the first section of the P3 air pipe if the inspected clearance is found to be incorrect.

e.     Replace RH rear half-wall if any damage is found.

2.    If the play between the P3 air pipe (first section) and the RH rear half wall is still not compliant repeat the inspection as detailed in Requirement 1 of this AD.

Note 2:  EASA AD 2008-0134R1 dated 17 February 2009 refers.

Compliance:

For Requirement 1 - Within 100 flight hours after the effective date of this AD, unless previously accomplished and the play between the P3 air pipe (first section) and the RH rear half wall was found to be compliant.

For Requirement 2 - At intervals not exceeding 100 flight hours.

This Amendment becomes effective on 9 April 2009.

Background:

On several ARRIUS 2F engines, the clearance between the P3 air pipe part number (P/N) 0319719180 and the rear right bulkhead P/N 0319998240 has been found to be too small.

Investigations have shown that both P3 air pipe and rear right bulkhead were compliant to the design.  The Turbomeca Engineering Department concluded that the tolerance of assembly established during the design could result in some rubbing between parts.

Rubs between the pipe and the bulkhead may lead to premature wearing and finally rupture of the P3 air pipe.  The loss of P3 air pressure would then force the fuel control system to idle which could have a detrimental effect in critical phases of flight.

This amendment requires repeat inspections for those pipes found to be non compliant with the service bulletin.

The original issue of this AD became effective on 28 September 2008.

James Coyne
Delegate of the Civil Aviation Safety Authority

27 February 2009