AD/A109/38 Amdt 1 Tail Rotor Blades (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/A109/38 and issues the following 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/A109/38 Amdt 1 Tail Rotor Blades 2/2007

Applicability:

All Model A109E helicopters equipped with part number 109-8132-01-111 tail rotor blades.

Requirement:

Action in accordance with the requirements of Agusta Technical Bulletin 109EP-30 Revision C.

This Directive shall be entered on the Maintenance Release as maintenance required. The Requirement document Part II visual inspections may be performed and certified by the Pilot in Command who has been trained to do the inspection by an appropriately qualified person.  In this case, a copy of the Requirement document and this Directive is to be carried in the aircraft.

Note:  EASA AD 2006-0353 refers.

Compliance:

As specified in the Requirement document.

This Amendment becomes effective on 15 February 2007.

Background:

The manufacturer received reports of cracked part number 109-8132-01-111 tail rotor blades.  Analysis and tests have shown that the cracking was caused by fatigue, as a result of unanticipated loads on the tail rotor blades.  The manufacturer has redesigned the tail rotor grip bushings to reduce these loads.  Until the tail rotor grip assembly is modified, the life limit of the tail rotor blades is reduced to 200 hours time in service.  If not corrected, fatigue failure of the tail rotor blade could lead to loss of control of the helicopter.

Amendment 1 is issued in response to a new EASA AD, which extends the inspection interval of the tail rotor blade bushing from 150 flight hours to 200 flight hours as specified in Revision C of the Requirement document.

David Villiers
Delegate of the Civil Aviation Safety Authority

5 January 2007