AD/DHC-8/11 Amdt 1 - Engine Cowl Door Retention and Pressure Relief

Overview

The Civil Aviation Regulations 1998, which were enacted to regulate and ensure the safety of civil aviation in Australia, were amended to address specific safety concerns related to Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes. This particular legislative instrument, F2006B09166, was introduced by the Civil Aviation Safety Authority to mitigate risks associated with the loss of engine cowl doors during engine fires, which can compromise the effectiveness of the fire extinguishing system. The policy objective is to ensure the safety of the aircraft and its occupants by mandating modifications to the engine cowlings in accordance with the latest service bulletin from the manufacturer, reflecting the need for updated safety standards to prevent catastrophic outcomes. The enactment by the Commonwealth of Australia aims to align with international safety directives, particularly referencing the Canadian AD CF-89-15, and mandates compliance by a specific deadline, underscoring the urgency and importance of these safety measures. This legislative instrument is part of the ongoing effort by the Civil Aviation Safety Authority to maintain high safety standards in the aviation industry, ensuring that all aircraft operating within Australian airspace meet stringent safety requirements.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to the Bombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes, including model 100 series serial numbers 1 to 156 and 158 to 199, and model 300 series serial number 124. The regulation mandates modifications to both the engine and engine cowlings to ensure they comply with DHC S.B. No. 8-71-13 Rev C, which addresses issues of engine cowl door retention and pressure relief. This requirement is a response to past incidents where the loss of engine cowl doors during engine fires rendered the fire extinguishing system ineffective. The regulation demands compliance with these modifications by 30 November 1990, and it references the Canadian AD CF-89-15. The regulation's reach extends to ensuring the safety of these aircraft through the specified modifications, with no explicit exclusions or exemptions mentioned within the provided text. The application of this directive may be further detailed or extended through subordinate instruments issued by the Civil Aviation Safety Authority.

Key Provisions

The key operative sections of the Civil Aviation Regulations 1998, specifically Part 39 - 105, are concerned with airworthiness directives. Section 39.105(1) mandates the modification of engine cowlings on Bombardier (Boeing Canada/De Havilland) DHC-8 Series aeroplanes. This modification aims to address the issue of engine cowl door loss during engine fires, which can render the fire extinguishing system ineffective. The specific requirement is detailed in Amendment 1 (AD/DHC-8/11Amdt 1) issued on 4 September 1990, which refers to DHC Service Bulletin No. 8-71-13 Rev C. This amendment applies to Model 100 series serial numbers 1 to 156 and 158 to 199, and Model 300 series serial number 124. The obligations imposed by this directive on the relevant parties, primarily aircraft operators and maintenance providers, include ensuring that the specified modifications are implemented on the affected aircraft before the compliance deadline of 30 November 1990. The modifications must be carried out in accordance with the detailed instructions provided in DHC Service Bulletin No. 8-71-13 Rev C. This ensures that the engine cowlings are properly retained and that the pressure relief mechanisms are effective, thereby mitigating the risk of engine cowl door loss during a fire. Failure to comply with the requirements set out in the airworthiness directive may result in significant consequences. Under Section 39.105(2), non-compliance with these directives can lead to serious safety risks, including the potential for engine fires to become uncontrollable, leading to catastrophic outcomes. The regulations do not explicitly state civil or criminal penalties for non-compliance in this context, but the enforcement of such directives is critical for maintaining the safety standards required by the Civil Aviation Safety Authority (CASA). Non-compliance could also result in the grounding of the aircraft until the required modifications are made, which can have significant operational and financial implications for the operators.