Ad/Arrius/11 - Fuel Control Unit "Delta P" Diaphragm (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.
Turbomeca Turbine Engines - Arrius Series
| AD/ARRIUS/11 | Fuel Control Unit "Delta P" Diaphragm | 11/2005 |
Applicability: | TURBOMECA ARRIUS 2F turboshaft engines equipped with a fuel control unit (FCU) whose serial number is given in the list appended to Mandatory Service Bulletin No. A319 73 4825 or later DGAC approved revision. |
Requirement: | Replace the FCU in accordance with Turbomeca Alert Service Bulletin No. Note: DGAC AD F-2005-143R1 EASA reference No 2005-6192 dated 22 August 2005 refers. |
Compliance: | At the latest by 28 February 2006. |
| This Airworthiness Directive becomes effective on 27 October 2005. | |
Background: | This Directive is issued following the case of an increase in fuel flow resulting from deterioration of the constant delta pressure diaphragm. The increase in fuel flow led to an increase in gas generator rating which resulted in an increase in power turbine and helicopter rotor rating. This then led to an uncommanded in-flight engine shut-down following power turbine blade-shedding (blades contained) due to overspeed. This increase in fuel flow is attributed to the deterioration of the constant delta pressure diaphragm installed the wrong way round. The aim of this Directive is to replace the diaphragm potentially installed in the wrong way by one having two projections indicating proper direction. |
James Coyne
Delegate of the Civil Aviation Safety Authority
15 September 2005
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