AD/SD3-60/40 Amdt 1 - Flight Controls Rudder Gust Lock System

Overview

The Civil Aviation Regulations 1998, as amended by the Legislative Instrument F2006B06886, specifically address the safety of Short SD3-60 Series aeroplanes, particularly focusing on the flight controls and the rudder gust lock system. This legislation was introduced to rectify issues identified in the original design of the rudder gust lock system, which could potentially lock the rudder under certain conditions, thereby posing a safety risk. The Civil Aviation Safety Authority (CASA), as the regulatory body responsible for the safety oversight of civil aviation in Australia, issued this directive to mandate modifications to the rudder gust lock electrical circuit to enhance the safety of these aircraft. The policy objective behind this legislative instrument is to ensure that all SD3-60 aircraft comply with the updated safety standards, thereby reducing the risk of accidents associated with the improper functioning of the rudder gust lock system. This legislative instrument reflects the ongoing commitment of CASA to address identified safety concerns in civil aviation by ensuring that aircraft meet stringent safety requirements. The requirement for compliance with the updated Service Bulletin from Short Brothers PLC, as classified as mandatory by the Civil Aviation Authority (UK), underscores the collaborative effort among international aviation authorities to maintain high safety standards. The directive mandates that all affected SD3-60 aircraft must implement the specified modifications to the rudder gust lock system prior to a specified compliance date, ensuring that the safety of these aircraft is consistently upheld.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, apply to all SD3-60 aircraft listed in Short Brothers PLC Service Bulletin SD360-27-23 Revision No 1 dated 15 April 1994. This directive mandates modifications to the rudder gust lock electrical circuit in accordance with the specified service bulletin, which has been classified as mandatory by the Civil Aviation Authority (UK). This regulation ensures that the electrical control circuit of the rudder gust lock system is altered to incorporate a time delay relay, preventing the premature locking of the rudder if the actuator experiences runaway in flight. The directive aims to enhance the safety of these aircraft by ensuring that the weight on wheels switch is closed before the rudder can lock, thereby preventing potential malfunctions during flight. The applicability of this directive is limited to the specified SD3-60 aircraft, and compliance must be achieved before 28 July 1994. The directive allows for minor changes to the wiring and accomplishment instructions as outlined in the revised requirement document, but it maintains the same compliance deadline.

Key Provisions

The primary operative sections of the Civil Aviation Regulations 1998, PART 39 - 105, specifically AD/SD3-60/40 Amendment 1, mandate modifications to the rudder gust lock electrical circuit for all SD3-60 series aeroplanes. The applicable aircraft are those listed in Short Brothers PLC Service Bulletin SD360-27-23 Revision No 1, dated 15 April 1994. The main requirement (Section 39-105(1)) is to modify the rudder gust lock electrical circuit according to the specifications outlined in the aforementioned Service Bulletin. This directive, classified as mandatory by the UK Civil Aviation Authority (CAA), aims to prevent the locking of the rudder under certain conditions, particularly when the weight on wheels switch is closed and the actuator has runaway in flight. The modification includes the introduction of a time delay relay in the circuit to delay the possible locking of the rudder. This directive was originally issued to address safety concerns, and the current amendment reflects minor changes to the wiring and accomplishment instructions, as detailed in the Requirement Document. The obligations imposed by this legislation on the relevant parties, primarily aircraft operators and maintenance providers, include ensuring that the modifications to the rudder gust lock electrical circuit are performed correctly and in compliance with the Service Bulletin SD360-27-23 Revision No 1. The compliance date for these modifications is set as prior to 28 July 1994, underscoring the urgency and importance of adhering to the specified timeline. Operators and maintenance providers must ensure that all necessary modifications are completed by this date to avoid any non-compliance issues. This includes meticulous documentation of the modifications, verification of the implemented changes, and ensuring that the aircraft meet the safety standards set by the Civil Aviation Regulations. Failure to comply with the provisions of this legislation can lead to various consequences. Firstly, the introduction of a time delay relay and the subsequent modifications are mandatory, and non-compliance can result in serious safety risks, potentially leading to operational disruptions and grounding of the aircraft. Additionally, there may be civil penalties imposed for non-compliance, as the Civil Aviation Regulations 1998 outline various sanctions for failure to adhere to airworthiness directives. The specific penalties can include fines and potential criminal charges for individuals or entities found guilty of non-compliance, with maximum penalties varying based on the severity of the breach and its impact on aviation safety. The enforcement of these provisions is crucial to maintaining high safety standards within the aviation industry.