AD/A109/53 Tail Rotor Flange Assembly (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.

Agusta A109 Series Helicopters

AD/A109/53 Tail Rotor - Flange Assembly 7/2006 TX

Applicability:

Agusta A109S helicopters up to S/N 22010 except S/N 22007, where maintenance activity has been carried out at least once on the Flange Assembly P/N
109-0131-33-105 of the Tail Rotor Trunnion P/N 109-0131-30-101.

Requirement:

Check the torque applied to the Flange P/N 109-0131-33-105 in accordance with Agusta Alert “Bollettino Tecnico” 109S-2 or later approved revision.

Note:  EASA Emergency AD 2006-0120-E dated 15 May 2006 refers.

Compliance:

Before further flight after the effective date of this AD.

This Airworthiness Directive becomes effective on 18 May 2006.

Background:

The failure of  the threaded pin of Trunnion P/N 109-0131-30-101 on an Agusta A109S caused the subsequent loss of the connected Flange P/N 109-0131-33-105, resulting in a sudden and noticeable increase in the vibration level.  An investigation showed that the pin is likely to break due to over-torquing of Flange P/N
109-0131-33-105 during maintenance.

James Coyne
Delegate of the Civil Aviation Safety Authority

16 May 2006