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 550 (Citation II) Series Aeroplanes AD/CESSNA 550/26 Wing Fuel Boost Pumps 6/2006 DM Applicability: Cessna Model S550, 550 and 551 model aeroplanes with serial numbers as follows: Model Serial Number Range S550 0001 through 0160 inclusive 550 and 551 0002 through 0733 inclusive 550 0801 through 1075 inclusive Requirement: 1. If not previously accomplished, revise the Limitations Section of the applicable Cessna aircraft flight manual (AFM) to prohibit use of the wing fuel boost pumps for defueling under certain conditions, by inserting the applicable temporary change identified in Cessna Service Bulletin SB550-28-14, dated 2 December 2003, or in the following table. AFM Temporary Change Dated AFM 55BFM TC–R10–07 17 March 2004 Model 550 Citation Bravo 55BFM TC–R10–08 17 March 2004 Model 550 Citation Bravo 55BFM TC–R10–09 17 March 2004 Model 550 Citation Bravo S55CA TC–04–01 8 July 2004 Model S550 Citation S/II S55CA TC–04–02 8 July 2004 Model S550 Citation S/II S55CA TC–04–03 8 July 2004 Model S550 Citation S/II S55FM TC–04–01 4 March 2004 Model S550 Citation S/II S55FM TC–04–02 4 March 2004 Model S550 Citation S/II S55FM TC–04–03 4 March 2004 Model S550 Citation S/II 2. If not previously accomplished, install a placard close to the fuel quantity gauge, in accordance with the Accomplishment Instructions of the Cessna Service Bulletin SB550-28-08 dated 7 May 2004, SB550-28-14 dated 2 December 2003, or SB550-28-15 dated 20 January 2004, as applicable. In addition to the specifications in the service bulletin, the letters on the placard must be at least 6mm (1/4 inch) tall. 3. If not previously accomplished, carry out the following action in accordance with the Accomplishment Instructions of SB550-28-08, SB550-28-14, or SB550-28-15, as applicable: a. Do a detailed inspection for chafed wiring of the wing fuel boost pumps. b. Modify the wing fuel boost pumps. Note 1: For the purposes of this Directive, a detailed inspection is: "An intensive examination of a specific item, installation or assembly to detect damage, failure or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.'' 4. If as a result of the Requirement 3.a. inspection and discrepancies are detected, accomplish all applicable corrective and other specified actions in accordance with the applicable service bulletin. 5. Remove the Requirement 1 AFM temporary change and the Requirement 2 placard. 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 2006-05-08, are considered acceptable for compliance with the equivalent Requirements of this Directive. Note 2: FAA AD 2006-06-03 Amdt 39-14511 refers. Compliance: For Requirements 1 and 2 - Within 25 hours time in service (TIS) after the effective date of this Directive. For Requirement 3 - Within 300 flight TIS after the effective date of this Directive. For Requirement 4 - Before further flight, immediately following the Requirement 3.a. inspection. For Requirement 5 - Before further flight after the Requirement 3 inspection and modification are accomplished. This Airworthiness Directive becomes effective on 20 April 2006. Background: This Directive requires the revision of the AFM to initially prohibit use of the wing fuel boost pumps for defueling under certain conditions and the installation of a placard. The Directive subsequently requires the accomplishment of other specified investigative and corrective actions as necessary. Terminating action for this Directive is the modification of the wing boost pumps together with the removal of the AFM revision and placard. The FAA has received a report of a chafed electrical wiring harness, which was arcing inside the fuel tank. This Directive is issued to prevent potential fuel vapour ignition in a fuel tank, which could result in explosion and loss of the aeroplane. James Coyne Delegate of the Civil Aviation Safety Authority 4 April 2006