AD/SF340/97 DC Generating System Undervoltage Protection (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.

SAAB SF340 Series Aeroplanes

AD/SF340/97 DC Generating System - Undervoltage Protection 2/2005

Applicability:	SAAB SF340A Serial No. 004 to 159 inclusive, SAAB 340B Serial No. 160 to 367 inclusive.
Requirement:	Install a Generator Control Unit (GCU) model 51539-007B in accordance with SAAB AB Service Bulletin 340-24-026 Rev 2 dated 29 October 2004 or later revision.
Note 1:  Installation of GCU model 51539-007B terminates the repetitive brush inspection required by AD/SF340/96.
Note 2:  LFV AD No 1-197 (EASA Approval 2004-10860) refers.
Compliance:	No later than three years after the effective date of this Directive.
This Airworthiness Directive becomes effective on 17 February 2005.
Background:	A premature failure of the generator can cause a low voltage situation in flight, if the aircraft is not equipped with the GCU 51539-007B.  This GCU was included in the type design from serial number 368 and has been available as an option for earlier manufactured aeroplanes.  Service experience has shown that installation of the new GCU is needed in order to meet the requirements of continued airworthiness in accordance with EC regulation 1702/2003 Part 21A.3B and associated guidance material.

James Coyne
Delegate of the Civil Aviation Safety Authority

13 December 2004

The above AD is notified in the Commonwealth of Australia Gazette on 26 January 2005.