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 CAR 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. Pratt and Whitney Canada Turbine Engines - PW 100 Series AD/PW 100/9 Fuel Heater 4/2001 Applicability: All PW100 Series engines not incorporating the improved fuel heater introduced by Pratt and Whitney Canada Service Bulletin PW100-72-21100. Requirement: 1. Replace Stewart Warner fuel heaters, P/No 10718 (all series numbers), with improved heaters in accordance with Pratt and Whitney Canada (PWC) Service Bulletin PW100-72-21100, Revision 2 and PWC Service Information Letter (SIL) PW100-074. 2. No person shall install a pre-SB PW100-72-21100 configuration fuel heater on an Australian registered aircraft. Note 1: Transport Canada AD CF-2000-34 refers. Note 2: Compliance with previous issues of SB PW100-72-21100 satisfies the intent of this Airworthiness Directive. Compliance: 1.(a) For fuel heaters listed in Tables 1 and 2 of SIL PW100-074, replace the fuel heater at the next scheduled low pressure fuel filter removal after the effective date of this Directive, or 31 August 2002, whichever occurs first. 1.(b) For fuel heaters not listed in Tables 1 and 2 of SIL PW100-074, replace the fuel heater no later than 31 August 2002. 2. After 19 May 2001. This Airworthiness Directive becomes effective on 19 April 2001. Pratt and Whitney Canada Turbine Engines - PW 100 Series AD/PW 100/9 (Continued) Background: There have been incidents where the studs that retain the fuel filter bowl have been pulled from the housing resulting in fuel leakage. The improved fuel heater and a review of maintenance practices will preclude fuel leaks associated with pulled studs. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 8 March 2001 The above AD is notified in the Commonwealth of Australia Gazette on 21 March 2001.