COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Ayres Thrush (Snow) Commander Series Aeroplanes
AD/AC-SNOW/16
Amdt 1
Rudder Horn Balance/Leading Edge Intersection
10/88
Applicability: All models S-2D and S-2R modified in accordance with Part 2 of AD/AC-SNOW/12. Requirement: 1. Remove the rudder from the aircraft.
2. Strip the fabric and dope from the intersection of the horn balance and the rudder leading edge in the region of the top hinge.
3. Inspect the intersection for cracking using a 10x glass paying particular attention to the hinge reinforcement weld edge.
4. If cracking is found repairs are to be carried out in accordance with AC 43.13 or a scheme approved by the Authority.
Note: Findings for all aircraft are to be reported to local airworthiness offices of the Authority.
Compliance: Within 10 hours’ time in service after 8 February 1988.
Background: The initial issue of the Directive was a one-time inspection pending an accident investigation for any further action. As a result of that accident investigation the Background is amended to note that the failure of the rudder structure in the area of the hinge modification has been attributed to undiscovered/unrectified cracking present at the time of the AD/AC-SNOW/12 modification. The undiscovered cracking continued to grow until rudder structural failure was inevitable.
Overview
The Civil Aviation Regulations 1998, specifically Part 39 - 105, introduced the Civil Aviation Safety Authority Schedule of Airworthiness Directives for the Ayres Thrush (Snow) Commander Series Aeroplanes, with the aim of addressing safety issues related to these aircraft models. This legislative instrument was enacted to ensure that any identified structural faults are rectified to maintain airworthiness and safety standards. The Civil Aviation Safety Authority, under the authority of the Australian Parliament, developed this schedule to provide clear directives and compliance requirements for aircraft operators, ensuring that safety measures are uniformly applied across the industry. The overarching policy objective is to prevent accidents and enhance the safety of civil aviation by mandating regular inspections and repairs of critical components, such as the rudder horn balance and leading edge intersection, to prevent structural failures.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, governs the airworthiness of Ayres Thrush (Snow) Commander Series Aeroplanes, particularly models S-2D and S-2R that have been modified in accordance with Part 2 of AD/AC-SNOW/12. This regulation applies to all relevant aircraft operators within the Commonwealth of Australia and mandates certain actions to ensure the structural integrity of the rudder. The requirement includes the removal of the rudder from the aircraft, stripping of fabric and dope from the intersection of the horn balance and rudder leading edge, and an inspection for cracking, with particular attention to the hinge reinforcement weld edge. Should any cracking be found, repairs must adhere to AC 43.13 or an approved scheme. Non-compliance with these directives within the stipulated timeframe of 10 hours’ time in service after 8 February 1998 could result in safety concerns, and thus, all findings must be reported to the local airworthiness offices of the Authority.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandate the Airworthiness Directive (AD) for the Ayres Thrush (Snow) Commander Series Aeroplanes, with the focus on the rudder horn balance and leading edge intersection (AD/AC-SNOW/16 Amendment 1). This directive applies to all models S-2D and S-2R that have been modified in accordance with Part 2 of AD/AC-SNOW/12. The directive's requirements are detailed in the main text, with the primary tasks being the removal of the rudder, stripping of fabric and dope at the intersection, inspection for cracking, and subsequent repairs if necessary.
These requirements are quite specific and demand meticulous attention to detail. Firstly, the rudder must be removed from the aircraft. Secondly, the fabric and dope must be stripped from the area where the horn balance meets the rudder leading edge, particularly around the top hinge. This is followed by an inspection of the intersection for any signs of cracking, using a 10x magnifying glass, with a focus on the hinge reinforcement weld edge. If any cracking is identified, the repairs must be carried out in accordance with AC 43.13 or an approved scheme. It is also crucial that findings from these inspections are reported to the local airworthiness offices of the Civil Aviation Safety Authority.
Compliance with AD/AC-SNOW/16 Amendment 1 must be achieved within 10 hours of the aircraft being in service after 8 February 1988. This timeframe underscores the urgency and importance of adhering to the directive. The background information provided indicates that the initial issue was a one-time inspection, pending an accident investigation. The investigation found that the failure of the rudder structure in the area of the hinge modification was due to undiscovered and unrectified cracking present at the time of the AD/AC-SNOW/12 modification. This cracking continued to grow until the structural failure of the rudder was inevitable.
Failure to comply with these directives could result in significant consequences. Non-compliance may lead to safety risks, as the directive is a direct response to identified structural issues that could compromise the safety of the aircraft. Additionally, there may be legal and regulatory repercussions, including fines, enforcement actions, or even the grounding of the affected aircraft until compliance is achieved. The specific penalties for non-compliance are not detailed in the text, but they could include civil or criminal penalties as determined by the relevant authorities.