AD/DHC-8/30 - Nose Wheel Steering Potentiometer Lever Stop

Overview

The Civil Aviation Regulations 1998 (Cth) were enacted to regulate civil aviation within Australia and ensure the safety and efficiency of the aviation industry. Among various other regulations, the instrument F2006B09186 focuses on a specific safety directive related to Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes. This directive was introduced to address a safety issue concerning the nose wheel steering potentiometer lever stop in the DHC-8 Series 100 aircraft, serial numbers 003 through 334. The problem identified was the inadequacy of the potentiometer stops in the nose gear steering system, which could lead to excessive uncontrolled potentiometer lever movement in the event of a mechanical link failure between the rudder pedals and the potentiometer. Such a failure could potentially cause the aircraft to depart from the runway during critical phases of flight such as take-off or landing. The directive mandates compliance by requiring the implementation of de Havilland Modification 8/1809, as per de Havilland Service Bulletin 8-32-99 Revision A, by a specified date of 15 May 1994. This directive was enacted by the Civil Aviation Safety Authority under the authority granted by the Civil Aviation Act 1988 (Cth) to safeguard air travel by ensuring the airworthiness of aircraft operating within Australian airspace.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to airworthiness directives issued by the Civil Aviation Safety Authority (CASA) and applies to the Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes, with a focus on the nose wheel steering potentiometer lever stop for model DHC-8 Series 100 aircraft with serial numbers ranging from 003 through 334. This regulation is concerned with ensuring the safety of aircraft by requiring modifications to prevent potential hazardous conditions arising from mechanical failures in the nose gear steering system. The directive mandates that de Havilland Modification 8/1809 must be completed in accordance with de Havilland Service Bulletin 8-32-99 Revision A, with compliance required before 15 May 1994. This requirement is aimed at addressing the issue where the potentiometer stops are too short, which could lead to excessive uncontrolled lever movement, and potentially cause the aircraft to depart the runway during critical phases of flight such as take-off or landing. This legislative instrument extends its jurisdictional reach across the Commonwealth of Australia, ensuring that the safety standards set forth are uniformly applied to the specified aircraft within its territory.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, contains a schedule of airworthiness directives which includes AD/DHC-8/30. This directive (section 39-105) applies to the Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes, particularly the model DHC-8 Series 100 aircraft with serial numbers ranging from 003 to 334. The directive mandates the implementation of de Havilland Modification 8/1809, which aligns with de Havilland Service Bulletin 8-32-99 Revision A. It is noteworthy that this directive is also referenced in Transport Canada AD CF-93-24. The primary obligation imposed by this airworthiness directive is to ensure that the nose wheel steering potentiometer lever stop is adjusted or replaced in accordance with the specified modification. This requirement is critical to prevent the potentiometer stops from being too short, which could otherwise allow for excessive uncontrolled potentiometer lever movement. Such a condition, particularly in the event of a failure in the mechanical link between the rudder pedals and the potentiometer, could potentially lead to severe operational hazards, such as the aircraft departing the runway during take-off or landing. Compliance with AD/DHC-8/30 is mandatory and must be completed prior to 15 May 1994. This deadline ensures that all affected aircraft are modified in a timely manner to mitigate the identified safety risks. Failure to adhere to this directive could result in the aircraft being deemed unairworthy, leading to significant operational disruptions and safety concerns. In terms of enforcement, any breach of this airworthiness directive could result in severe consequences. The Civil Aviation Safety Authority (CASA) has the authority to take action against operators who fail to comply with these regulations. Potential penalties may include fines, suspension of airworthiness certificates, or other regulatory actions deemed necessary to ensure compliance and maintain aviation safety standards. The seriousness of these potential consequences underscores the importance of adhering to the directive's requirements to prevent any risk to flight safety.