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.
Bombardier (Boeing Canada/de Havilland) DHC-8 Series Aeroplanes
AD/DHC-8/82 Autopilot Servo Engagement 2/2002
DM
Applicability: DHC-8 Series 102, 103, 106, 201, 202, 301, 311, 314 and 315, with Serial Numbers
003 through 580 inclusive.
Requirement: 1. Determine through a visual inspection of the automatic flight control system, SM-300 servo drive assemblies, Part Numbers (P/N) 7002260-922 and -923, the serial numbers (S/N) of the aileron and elevator servo drives.
Note 1: P/N 7002260-922 applies to both the elevator servo drive unit installed in Series 100, 200 and 300 aircraft and to the aileron servo drive unit installed in Series 300 aircraft.
Note 2: P/N 7002260-923 applies to the aileron servo drive units installed in Series 100 and 200 aircraft.
2. Remove and replace aileron and elevator servo drive assemblies (P/Ns 7002260- 922 and -923) that have a serial number with the last four digits in the range from 4826 through 5935 (i.e. xxxx 4826 through xxxx 5935) with servo drive assemblies complying with the following:
- If P/N 7002260-922 is removed, replace with servo drive assembly
P/N 7002260-722 or with servo drive assembly P/N 7002260-922 that has a serial number with the last four digits being 4825 or lower.
b. If P/N 7002260-923 is removed, replace with servo drive assembly
P/N 7002260-723 or with servo drive assembly P/N 7002260-923 that has a serial number with the last four digits being 4825 or lower.
Bombardier Alert Service Bulletin A8-22-18 dated 06 September 2001 or Revision A dated 18 September 2001, provides approved instructions for replacing the servo drive units.
3. Aileron and elevator servo drive assemblies (P/Ns 7002260-922 and -923) that have a serial number with the last four digits in the range from 4826 through 5935 shall not be installed in any aircraft.
Note 3: Transport Canada AD CF-2001-40 refers.
Bombardier (Boeing Canada/de Havilland) DHC-8 Series Aeroplanes
AD/DHC-8/82 (continued)
Compliance: For Requirement 1 - Before 28 December 2002.
For Requirement 2 - Before 28 December 2002.
For Requirement 3 - As of the effective date of this Directive.
This Airworthiness Directive becomes effective on 28 December 2001.
Background: A Transport Canada investigation, of an incident involving higher than normal aileron control forces, determined that screws in the SM-300 autopilot clutch assembly had backed out sufficiently, causing the clutch to mechanically engage the autopilot servo. The screws were able to back out due to the type of screw adhesive used during manufacture of the unit.
This Directive requires the replacement of affected servo drive units and limits their installation on aeroplanes as replacement parts.
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 12 December 2001
The above AD is notified in the Commonwealth of Australia Gazette on 19 December 2001.
Overview
The Civil Aviation Safety Authority (CASA) has issued an Airworthiness Directive (AD) under subregulation 39.1(1) of the Civil Aviation Regulations 1998 (CAR 1998) to address a safety issue with the autopilot servo drive assemblies in Bombardier (Boeing Canada/de Havilland) DHC-8 Series aeroplanes. This AD, titled "AD/DHC-8/82 Autopilot Servo Engagement," was introduced to correct an unsafe condition discovered during a Transport Canada investigation. This investigation found that screws in the SM-300 autopilot clutch assembly had backed out, causing the clutch to engage the autopilot servo mechanically. The screws were prone to backing out due to the type of screw adhesive used during the manufacture of the unit. The AD applies to DHC-8 Series 102, 103, 106, 201, 202, 301, 311, 314, and 315 aeroplanes with serial numbers 003 through 580 inclusive. The directive requires specific actions to be taken before 28 December 2002, including a visual inspection of the automatic flight control system, removal and replacement of affected servo drive assemblies, and prohibition of the installation of certain servo drive assemblies in any aircraft.
Scope and Application
The Airworthiness Directive (AD) AD/DHC-8/82 issued by the Civil Aviation Safety Authority (CASA) pertains specifically to Bombardier (Boeing Canada/de Havilland) DHC-8 Series Aeroplanes, including models 102, 103, 106, 201, 202, 301, 311, 314, and 315 with serial numbers ranging from 003 to 580. The directive applies to the automatic flight control system, specifically the SM-300 servo drive assemblies with part numbers 7002260-922 and -923, and concerns the replacement of aileron and elevator servo drives that have serial numbers within a specific range. The AD is applicable throughout the Commonwealth of Australia, as it is issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998, which grants CASA the authority to issue such directives to ensure the safety of aircraft within the country. The directive sets out clear requirements for inspecting, replacing, and prohibiting the installation of certain servo drive assemblies to address an unsafe condition identified by Transport Canada. Compliance with the AD is mandatory, with specific deadlines for each requirement, and the directive becomes effective from 28 December 2001.
Key Provisions
The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998, mandates certain actions to rectify an unsafe condition identified in specific DHC-8 series aeroplanes. Section 1 of the AD requires a visual inspection of the automatic flight control system to identify the serial numbers of the aileron and elevator servo drives (section 1(a)). Specifically, the directive refers to servo drive assemblies with part numbers 7002260-922 and 7002260-923, where the aileron and elevator servo drives need to be identified (section 1(a)(i)). Section 2 of the AD mandates the removal and replacement of aileron and elevator servo drive assemblies that have serial numbers within a specified range (section 2(a)). This requirement applies to assemblies with part numbers 7002260-922 and 7002260-923, where the serial number's last four digits fall between 4826 and 5935. These units must be replaced with servo drive assemblies that meet the criteria specified in the AD (section 2(b)). Section 3 of the AD prohibits the installation of servo drive assemblies with serial numbers in the specified range (section 3(a)).
The AD imposes several obligations on the parties governed by it. Firstly, it requires that the visual inspection of the automatic flight control system be conducted and documented before 28 December 2002 (section 1(a)). Secondly, the removal and replacement of the specified servo drive assemblies must also be completed by 28 December 2002 (section 2(a)). Lastly, the directive mandates that servo drive assemblies with serial numbers in the specified range cannot be installed in any aircraft as of the effective date of the directive (section 3(a)).
Failure to comply with the AD may result in various consequences. Section 4 of the AD indicates that it becomes effective on 28 December 2001, and non-compliance with the specified requirements may lead to civil or criminal penalties as outlined in the Civil Aviation Act 1988 and the Civil Aviation Regulations 1998. The specific penalties for non-compliance are not detailed in the AD but may include fines and imprisonment as provided under the relevant legislation.