AD/Cessna 550/25 Amdt 1 Engine Fire Bottle Wiring (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/CESSNA 550/25 and issues the following 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 550 (Citation II) Series Aeroplanes

AD/CESSNA 550/25 Amdt 1 Engine Fire Bottle Wiring 8/2007

Applicability:	Model 550, 551 and S550 aeroplanes as identified in the following Cessna Service Bulletins (SB):
Model 550 551 S550	SB SB550-26-05 SB550-26-05 SBS550-26-02	Revision Original Original Original	Date 1 April 2005 1 April 2005 1 April 2005
Requirement:	1.    If not previously accomplished in accordance with the original issue of this Directive, install identification sleeves on the wires for the positive and negative terminal studs of the engine fire extinguishing bottles; re-connect the wires to the correct studs; test the connection and re-connect the wires again as applicable until the connection tests correctly.  The above actions are to be accomplished in accordance with Cessna SB550-26-05 or SBS550-26-02 as applicable.
2.    Fire extinguisher bottles may not be installed, as replacement spares, on any Cessna Model 550, 551 or S550 aeroplane unless identification sleeves have been installed on the wires for the positive and negative terminal studs in accordance with Requirement 1.
Later revisions of the above SB(s), approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2007-11-17, are considered acceptable for compliance with the equivalent Requirements of this Directive.
Note:  FAA AD 2007-11-17 Amdt 39-15074 refers.
Compliance:	For Requirement 1 - Within 100 hours time in service or 60 days after the effective date of this Amendment, whichever occurs first.
For Requirement 2 - As of the effective date of this Amendment.
This Amendment becomes effective on 2 August 2007.

Background:	The FAA has received reports of mis-wired fire extinguisher bottles, this could result in the circuit breaker disengaging (popping) when an attempt was made to discharge the bottles.
The original issue of this Directive required the installation of identification sleeves on the wires for the positive and negative terminal studs of the engine fire extinguishing bottles together with re-connecting the wires to the correct terminal studs.  These actions ensured that the fire extinguishing bottles may be activated in the event of an engine fire and that flammable fluids are not supplied during a fire, which could result in an unextinguished fire in the nacelle.
This Amendment continues the requirements of the original issue, extends the applicability to include Model 551 aeroplanes and includes a new requirement regarding replacement fire extinguisher bottles.
The original issue of this Directive became effective on 11 May 2006.

David Punshon
Delegate of the Civil Aviation Safety Authority

19 June 2007