AD/EC 225/8 Main Gearbox (MGB) Suspension Bar Fittings (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 225/8 Main Gearbox (MGB) Suspension Bar Fittings 11/2008

Applicability:

EC 225 LP helicopters, all serial numbers.

Requirement:

1.    Check the tightening torque of the bolts that secure the front Main Gearbox (MGB) bar attaching fitting in accordance with the instructions specified in paragraph 2.B of Eurocopter Alert Service Bulletin No. 05A002 Revision 1 or later approved revision.

2.    Check the tightening torque of the bolts that secure the front MGB bar attach fitting and the rear RH and LH MGB bar attach fittings, in accordance with the instructions specified in paragraph 2.B of Eurocopter Alert Service Bulletin
No. 05A002 Revision 1 or later approved revision.

Interpret the results of these two inspections in accordance with the criteria specified in paragraph 2.B.3 of Eurocopter Alert Service Bulletin No. 05A002 Revision 1 or later approved revision.

After results interpretation, readjustment of tightening torques and checking for cracks in attach fitting bolts and frame 3855 and 5295 are performed in accordance with paragraphs 2.B.4 and 2.B.5 of Eurocopter Alert Service Bulletin No. 05A002 Revision 1 or later approved revision.

Note:  EASA AD 2006-0163 Revision 1, dated 13 December 2007 refers.

Compliance:

1.    At the next scheduled 750 hour inspection, not exceeding 825 flight hours.

2.    Intervals not to exceed 825 flight hours.

This Airworthiness Directive becomes effective on 23 October 2008.

Background: This Airworthiness Directive is issued following re-analysis of tightening torques which showed that loss of MGB bar attach fitting tightening torque was occurring in service.  Significant loss in tightening torque can lead to a change in the loading modes of frames 3855 and 5295 and can cause crack initiation in the MGB bar attaching fittings.

David Villiers
Delegate of the Civil Aviation Safety Authority

27 August 2008