AD/EC 225/11 Main Gear Box Epicyclic Reduction Gear Module (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.

Eurocopter EC 225 Series Helicopters

AD/EC 225/11 Main Gear Box Epicyclic
Reduction Gear Module 6/2009 TX

Applicability:

Eurocopter EC 225 LP helicopters.

Requirement:

1.    Disassemble and inspect the main gearbox (MGB) epicyclic reduction gear module in accordance with paragraph 2.B.2 of Eurocopter EC225 ASB
No. 05A017 initial issue dated 10 April 2009.

2.    a.     Check the helicopter maintenance records in order to determine if, within the last 200 flight hours (FH) prior to the effective date of this AD, one or more particles were detected on the electric magnetic plug of the epicyclic reduction gear module without ensuing complete disassembly and inspection of the module.

b.    If detection occurred and was not followed by maintenance as defined above, disassemble and inspect the MGB epicyclic reduction gear module in accordance with paragraph 2.B.2 of Eurocopter EC225 ASB No. 05A017 initial issue.

3.    Do not install on any helicopter a MGB, unless its condition has been checked in accordance with the requirements of this AD.

The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD.

Note:  EASA Emergency AD 2009-0087-E dated 11 April 2009 refers.

Compliance:

For Requirement 1 - After the effective date of this AD, each time particles are detected on the electric magnetic plug of the MGB epicyclic reduction gear module, before further flight.

For Requirement 2.a. - Before next flight after the effective date of this AD.

For Requirement 2.b. - Before further flight.

For Requirement 3 - After the effective date of this AD.

This Airworthiness Directive becomes effective on 15 April 2009.

Background:

This emergency Airworthiness Directive (AD) is issued following the accident of the AS 332 L2 helicopter registered G-REDL that occurred on the 1st of April 2009, off the coast of Scotland near Aberdeen.

The investigation is still in progress and at this early stage, the cause of this accident seems to be connected with a degradation of the epicyclic module of the MGB, the root cause of which is still to be determined.  In the light of this information, the detection of any contamination of the MGB is of utmost importance as a precautionary measure.

For the reasons described above, this AD requires a check of the magnetic plug of the MGB epicyclic reduction gear module on a daily basis and to ensure also that correct MGB maintenance has been applied in case a particle was found on the magnetic plug before issuance of this AD.

James Coyne
Delegate of the Civil Aviation Safety Authority

14 April 2009