AD/AS 355/84 Stabilisers Upper and Lower Vertical Fin Spars (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 39.1 (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.

Eurocopter AS 355 (Twin Ecureuil) Series Helicopters

AD/AS 355/84 Stabilisers - Upper and Lower Vertical
Fin Spars 2/2005 DM

Applicability:

All Model AS 355 helicopter versions E, F, F1, F2, and N.

Requirement:

Inspect the spar of the upper and lower fins for cracks in accordance with Eurocopter AS 355 Alert Telex No. 05.00.44.

If a crack is found in one of the spars, before further flight, replace the affected vertical fin in accordance with Maintenance Manual Work Card 55.00.00.402.

Note:  DGAC AD F-2005-006 refers.

Compliance:

Within 25 flight hours after 12 January 2005, and thereafter at intervals not to exceed 100 flight hours.

This Airworthiness Directive becomes effective on 12 January 2005.

Background:

Reports were received of cracks discovered in the spar of the upper vertical fin on two AS 355 N helicopters.  Undetected cracking on the attachment spar of a vertical fin could lead to failure of the spar, and result in loss of the vertical fin.

David Punshon
Delegate of the Civil Aviation Safety Authority

6 January 2005