AD/Ecureuil/129 Seat Electrical Bonding 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/129 Seat Electrical Bonding Modification 2/2008 DM

Applicability:

All EC 130B4 Helicopters, pre Eurocopter Mod 073380, fitted with Sicma Type 159 energy absorbing seats.

Requirement:

Remove the electric bonding strap of Sicma Type 159 energy absorbing seats as instructed in Eurocopter Alert Service Bulletin No. 25A025.

Note:  EASA AD 2007-0311.

Compliance:

Within the next 110 Flight Hours but no later than 3 months, after the effective date of this Airworthiness Directive.

This Airworthiness Directive becomes effective on 4 January 2008.

Background:

The Sicma type 159 energy-absorbing seat is electrically bonded with a braided bonding strap.  This bonding strap is secured to the base of the seat with a screw and nut assembly, the head which is in line with one of the two seat energy absorbers.  In the event of a “crash” landing with very rapid deceleration and with a corpulent person occupying the seat, this screw may interfere with the “energy absorbing” function.  This affects conformity with the EC130 certification requirements.

An analysis made recently by Eurocopter shows that this “electrical bonding” braided strap is not necessary.  Consequently, this Airworthiness Directive mandates the removal of the electrical bonding strap.

David Punshon
Delegate of the Civil Aviation Safety Authority

3 January 2008