AD/Ecureuil/131 Stabiliser Upper and Lower Fin Attachment Fitting Modification (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 AS 350 (Ecureuil) Series Helicopters

AD/ECUREUIL/131 Stabiliser Upper and Lower Fin
Attachment Fitting - Modification 9/2008

Applicability:

Model AS 350 B, B1, B2, B3, BA, BB, and D helicopters, all serial numbers, fitted with the following upper and lower fins to which Modification (MOD) 073330 has not been incorporated:

Upper fin assembly part numbers 350A14-0020-00XX, -01XX, -02XX, -03XX,
-08XX, -10XX, -18XX, and -19XX.

Lower fin assembly part numbers 350A14-0021-00XX, -01XX, -02XX, and -04XX.

Requirement:

Remove the fins, modify the upper and lower fittings on the tail boom by increasing the diameter of the bolt holes, and replace bolts part number 22126BV060032L and washers part number 23112AG060LE with special bolts part number
350A23-4016-20 and special washers part number 350A23-4017-22; in accordance with EUROCOPTER AS 350 Alert Service Bulletin No. 55.00.16 Revision 0, or later EASA approved revision.

After 31 March 2009, upper and lower fins with part numbers listed in the applicability section of this Directive, and held as spares, shall not be installed on any helicopter unless MOD 073330 has been incorporated.

Note:  EASA AD 2008-0121 refers.

Compliance:

No later than 31 March 2009.

This Airworthiness Directive becomes effective on 28 August 2008.

Background:

The EASA received several reports of cracking in the stabiliser upper fin of Model AS 355 N helicopters.  The growth of a crack in a fin attachment spar, unless detected and corrected, could lead to failure of the spar and loss of the fin.

The EASA AD related to this Directive, AD 2008-0121, supersedes EASA ADs 2006-0060-E (AD/ECUREUIL/118) and 2006-0095 (AD/ECUREUIL/107 Amdt 1), and thereby constitutes terminating action to the requirements of these CASA ADs.

David Villiers
Delegate of the Civil Aviation Safety Authority

7 July 2008