1AD/AS 355/75 Amdt 1 - MGB Free-Wheel

COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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AIRWORTHINESS DIRECTIVE

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For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AS 355/75 and issues the following AD under subregulation 39.1 (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.

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Eurocopter AS 355 (Twin Ecureuil) Series Helicopters

AD/AS 355/75

Amdt 1

MGB Free-Wheel 4/2004 TX

Applicability: AS 355 E, F, F1, F2 and N model helicopters fitted with a combiner gearbox pre- MOD 077212 that has less than 10 flying hours since new, or since overhaul or since repair.

Requirement: Replace the free wheel rollers in the combiner gearbox as detailed in Eurocopter Alert Telex No. 63.00.21 R2

Note: DGAC Telex AD UF-2004-021 refers.

Compliance: Prior to further flight

This Amendment becomes effective on 26 February 2004.

Background: This amendment is in response to the manufacturer now identifying that the problem of slippage is not caused by insufficient cleaning of preservation fluid, but due to a change in the process that is applied to the free wheel rollers. The change from the “Bonderite” to “Parcolubrite” process has not provided the free wheel adherence in the first few hours of operations. Subsequently the applicability and the requirements now detailed are to address the cause of the problem.

This directive was issued to address a report of an engine overspeed event involving an AS355 helicopter during the single engine phase of an acceptance flight. The engine overspeed resulted from free-wheel clutch slippage was originally believed to be due to insufficient cleaning of preservation fluid from the main gearbox.

The original issue of this Directive became effective 21 January 2004.

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James Coyne

Delegate of the Civil Aviation Safety Authority 23 February 2004