AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/CESSNA 525/3 and issues the following 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. Cessna 525 Series Aeroplanes AD/CESSNA 525/3 Amdt 1 Electric Pitch Trim System 13/2003 TX Applicability: Model 525 aeroplanes, serial numbers 525- 0001, 525-0002 and 525-0004 through 525-0159 inclusive, without a Trim PC Board Assembly part number (P/N) 6518351- 8 installed. Requirement: 1. Unless previously accomplished, disengage the PITCH TRIM circuit breaker located on the left circuit breaker panel and install a tie strap (P/N MS3367-1- 4 or equivalent part number) on the shaft of the PITCH TRIM circuit breaker to prevent the circuit breaker from being engaged. 2. Unless previously accomplished, disengage the AP SERVOS circuit breaker located in the right circuit breaker panel and install a tie strap (P/N MS3367-1-4 or equivalent part number) on the shaft of the AP SERVOS circuit breaker to prevent the circuit breaker from being engaged. Note 1: Installation of Trim PC Board Assembly P/N 6518351-8, in accordance with Cessna Citation Alert Service Letter ASL525-27-02, dated 10 October 2003, is considered an optional terminating action for Requirements 1 and 2 of this Directive. Note 2: The Minimum Crew portion of Section II - Operating Limitations of the Aircraft Flight Manual (AFM) provides information on applicable operating limitations with the autopilot inoperable. Note 3: FAA AD 2003-21-07 Amdt 39-13342 and FAA Wichita Aircraft Certification Office Alternate Method of Compliance (AMOC) letter dated 22 October 2003 refer. Compliance: For Requirements 1 and 2 - Remains unchanged as "Within 5 calendar days or 10 hours time-in-service after the effective date of the original issue of this Directive, whichever occurs first". This Amendment becomes effective on 27 October 2003. Cessna 525 Series Aeroplanes AD/CESSNA 525/3 Amdt 1 (continued) Background: Following an accident involving a Cessna Model 525 aeroplane where the pilot ditched the aeroplane in the water and reported a problem with the pitch trim system, the United States Federal Aviation Administration (FAA) and Cessna carried out an analysis of the pitch trim system. This analysis revealed the potential for a single- wire shorting to 28 volts or a failure of a relay in the electric pitch trim system such that the relay contacts remain closed and precludes disconnect of the pitch trim using the control wheel autopilot/trim disconnect switch. The original issue of this Directive required the pitch trim circuit breaker and AP servo circuit breaker to be opened (disengaged) and tied to prevent them from being engaged. This action was designed to correct a single-point failure in the electric pitch trim system, which could result in a runaway pitch trim condition where the pilot could not disconnect using the control wheel autopilot/trim disconnect switch. This Amendment introduces an optional terminating action to the opening (disengaging) of the circuit breakers. The original issue of this Airworthiness Directive became effective on 24 October 2003. Jim Coyne Delegate of the Civil Aviation Safety Authority 23 October 2003 The above AD is notified in the Commonwealth of Australia Gazette on 27 October 2003.