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.
Overview
The Civil Aviation Safety Authority (CASA) issued the Airworthiness Directive (AD) AD/CESSNA 525/3 Amdt 1 on 23 October 2003, addressing a specific safety concern identified in the Cessna 525 series aeroplanes. This legislation was introduced to correct an unsafe condition related to the electric pitch trim system, which could lead to a runaway pitch trim scenario where the pilot cannot disconnect the system using the control wheel autopilot/trim disconnect switch. This issue was highlighted following an accident where the pilot of a Cessna Model 525 aeroplane had to ditch the aeroplane in the water due to a problem with the pitch trim system. The AD revokes the previous AD/CESSNA 525/3 and mandates that certain circuit breakers be disengaged and secured with tie straps to prevent engagement, with an optional terminating action available. The policy objective is to enhance aviation safety by mitigating the risk of unsafe conditions in the specified aircraft models.
Scope and Application
The Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) applies to specific Cessna 525 series aeroplanes, particularly those with serial numbers 525-0001, 525-0002, and 525-0004 through 525-0159 inclusive, unless they have already had a Trim PC Board Assembly part number 6518351-8 installed. The directive requires the disengagement of the PITCH TRIM and AP SERVOS circuit breakers to prevent them from being engaged, along with the installation of tie straps on the shafts of these circuit breakers. This action is necessary to correct a potential unsafe condition in the electric pitch trim system that could result in a runaway pitch trim condition. The directive does not specify any exclusions or exemptions, and the requirement to take action must be completed within five calendar days or 10 hours of time-in-service from the effective date of the directive, whichever is sooner. The directive extends across the Commonwealth of Australia and is effective as of 27 October 2003, following its notification in the Commonwealth of Australia Gazette.
Key Provisions
The Airworthiness Directive (AD) AD/CESSNA 525/3 Amdt 1 issued by the Civil Aviation Safety Authority (CASA) applies to specific model 525 aeroplanes, namely those with serial numbers 525-0001, 525-0002, and 525-0004 through 525-0159 inclusive, unless they already have a Trim PC Board Assembly part number (P/N) 6518351-8 installed (Applicability). The main requirements of this AD (Requirement) are for the aircraft operator to disengage the PITCH TRIM circuit breaker on the left circuit breaker panel and secure it with a tie strap (P/N MS3367-1-4 or equivalent) to prevent engagement. Similarly, the AP SERVOS circuit breaker located in the right circuit breaker panel must be disengaged and secured with a tie strap. Installation of Trim PC Board Assembly P/N 6518351-8 is considered an optional terminating action for these requirements. The compliance period for these actions is within 5 calendar days or 10 hours time-in-service after the effective date of the original issue of this Directive, whichever occurs first (Compliance).
The AD imposes specific obligations on the aircraft operators and owners of the affected model 525 aeroplanes. They must ensure that the PITCH TRIM and AP SERVOS circuit breakers are disengaged and secured as per the requirements, within the stipulated compliance period. This action is necessary to correct a potential unsafe condition related to the electric pitch trim system that could result in a runaway pitch trim condition. Failure to comply with these requirements could compromise the safety of the aircraft and its occupants.
Failure to comply with the AD can lead to serious consequences. The CASA, as the regulatory body, can enforce penalties and other sanctions for non-compliance with ADs. While the specific penalties are not detailed in this AD, non-compliance with ADs generally can result in enforcement actions such as fines, suspension or revocation of airworthiness certificates, and potential criminal charges in cases of serious non-compliance. The severity of the penalties depends on the nature and extent of the non-compliance and the potential risk to aviation safety it presents.