AD/DHC-8/32 - Landing Gear Hydraulic Selector Valve

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority, were enacted to ensure the safety and efficiency of civil aviation in Australia. This legislative instrument, specifically PART 39 - 105, addresses a critical safety issue concerning the Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes. The problem it was introduced to address is the risk of pilot valve leakage in certain DHC-8-100 series aircraft, which, if uncorrected, could potentially cause inadvertent landing gear retraction under low voltage conditions. This directive, known as AD/DHC-8/32, mandates compliance within a specified timeframe to mitigate such risks, ensuring the continued safety of the aircraft and its passengers. The policy objective is clearly to prevent aviation accidents by enforcing timely and necessary modifications to aircraft systems.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, governs the airworthiness directives applicable to Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes, including the directive AD/DHC-8/32 concerning the landing gear hydraulic selector valve. This directive applies to all DHC-8-100 series aircraft with serial numbers ranging from 003 through 038 that have not incorporated modification 8/0530. The requirement stipulates that unless the action outlined in de Havilland Dash 8 Alert Service Bulletin A8-32-117 has already been performed, the directive must be complied with. Compliance must be achieved within 300 hours of time in service from 30 June 1994, or by 30 October 1994, whichever is earlier. This directive is crucial to prevent pilot valve leakage, which, if left uncorrected, could, in conjunction with a low voltage condition, result in inadvertent landing gear retraction, a potentially hazardous situation.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 105, contain a directive regarding the airworthiness of certain Bombardier (Boeing Canada/De Havilland) DHC-8 series aeroplanes. This directive, AD/DHC-8/32, pertains to the landing gear hydraulic selector valve of the DHC-8-100 series aircraft with serial numbers (S/N) ranging from 003 to 038 that have not yet incorporated modification 8/0530 (Section 105.05). The directive mandates that unless the action specified in de HAVILLAND Dash 8 Alert Service Bulletin A8-32-117 has already been taken, the required action must be performed (Section 105.10). This directive is in alignment with Transport Canada's AD CF-94-05 (Section 105.15). Under these regulations, the primary obligation on the operators of affected aircraft is to ensure compliance with the directive within a specific timeframe. The compliance requirement is to perform the action within 300 hours of time in service from 30 June 1994, or by 30 October 1994, whichever date is sooner (Section 105.20). Failure to adhere to these compliance timelines can result in the aircraft being deemed non-airworthy, which could lead to operational restrictions and potential grounding of the aircraft until the necessary actions are completed. Breach of the airworthiness directive could lead to significant legal and operational consequences. While the specific civil or criminal penalties are not detailed in the directive, non-compliance with airworthiness directives generally can result in enforcement actions by the Civil Aviation Safety Authority (CASA). These actions can include fines, enforcement notices, or even prosecution under the Civil Aviation Act 1988, which could lead to substantial penalties. The severity of the penalty would depend on the nature and extent of the breach, as well as any resultant harm or risk posed to aviation safety.