AD/Cessna 525/6 Electrical Power Relay Circuit 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 39.001(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.

Cessna 525 Series Aeroplanes

AD/CESSNA 525/6 Electrical Power - Relay Circuit Protection 2/2008 DM

Applicability:	Model 525B aeroplanes, serial numbers 0001 through 0013 inclusive.
Requirement:	Unless already accomplished, incorporate electrical power relay circuit protection kit part number (P/N) SB525B-24-02 by following Cessna Citation Service Bulletin SB525B-24-02 Revision 1 dated 4 October 2007.
Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-23-16, are considered acceptable for compliance with the equivalent Requirements of this Directive.
Note:  FAA AD 2007-23-16 Amdt 39-15262 refers.
Compliance:	Either before 18 January 2008 or within the next 10 hours time-in-service after 19 December 2007, whichever occurs first.
This Airworthiness Directive becomes effective on 19 December 2007.
Background:	The FAA has received a report of a Model 525B aeroplane experiencing in-flight loss of numerous systems, tripped circuit breakers, together with burned wiring adjacent to the power distribution panel, this was a result of aircraft wiring left unprotected in the original design.
This Directive requires an electrical power relay circuit protection kit P/N SB525B-24-02 to be installed and is issued to correct an incorrect wiring installation and to provide short-circuit protection for all wiring from the aircraft power distribution system.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

7 December 2007