AD/AS 355/20 - Engine Fire Extinguishing System

Overview

The Civil Aviation Regulations 1998, as amended, include provisions under PART 39 - 105, addressing the safety of civil aircraft through the issuance of Airworthiness Directives (ADs). The AD/AS 355/20, issued by the Civil Aviation Safety Authority (CASA), is specifically tailored to ensure the airworthiness of Eurocopter AS 355 (Twin Ecureuil) Series Helicopters by mandating modifications to the engine fire extinguishing system. The objective of this directive is to prevent potential errors in the orientation of wiring and firing squibs, thereby enhancing the system's integrity and reducing the risk of accidental activation or failure during operation. This regulatory measure was introduced to address identified safety concerns, aligning with international standards and referencing relevant French Airworthiness Directives, to ensure that all affected helicopters meet the specified safety requirements within a stipulated timeframe.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all AS355 helicopters equipped with an engine fire extinguishing system that complies with specific Aerospatiale modifications or embodiments. This regulation mandates that the integrity of the fire extinguishing system must be ensured by adhering to the correct wiring and firing squib orientation as detailed in AS355 SB 2601 Revision 2 Figure 5. Non-compliance with these specifications may require the installation to be modified accordingly. The directive extends to all operators of AS355 helicopters within the Australian jurisdiction, demanding compliance within 30 hours after the issuance date of 9 June 1986. This regulation is underpinned by French A.D. 86-06-26(B), which further emphasises the importance of correct system installation to prevent issues such as the transposition of fire extinguisher bottles firing squibs. The applicability of this legislation is broad, targeting the safety and operational standards of civil aviation in Australia.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 105, includes the Civil Aviation Safety Authority Schedule of Airworthiness Directives (AD/AS 355/20) which applies to the Eurocopter AS 355 (Twin Ecureuil) Series Helicopters. This directive mandates that operators of AS355 helicopters equipped with an engine fire extinguishing system, as per Aerospatiale modifications AMS N.350A 07.0691, 0692, 1029, and 1043 or the embodiment of Aerospatiale AS355 S.B. 26.01, must ensure the integrity of the fire extinguishing system (section 39-105). It requires operators to consult AS355 SB 2601 Revision 2 Figure 5 for the correct orientation of wiring and firing squibs, and to modify the installation to align with these specifications if necessary. The directive is in response to the need to prevent the transposition of the fire extinguisher bottles firing squibs, as detailed in French A.D. 86-06-26(B). Operators of these helicopters are obligated to comply with the directive by making necessary modifications to the fire extinguishing system within 30 hours after 9 June 1986. This includes ensuring that the wiring and firing squibs are correctly oriented as specified in the referenced Service Bulletin. The objective is to maintain the safety and functionality of the fire extinguishing system, thereby reducing the risk of system failures during an engine fire. Operators must be proactive in reviewing and verifying their systems against the guidance provided in AS355 SB 2601 Revision 2 Figure 5 and making any required adjustments to meet the prescribed standards. Failure to comply with this directive can result in serious safety implications, potentially compromising the aircraft's ability to safely manage engine fires. While the Civil Aviation Regulations do not explicitly state penalties for non-compliance with this particular directive, non-compliance with airworthiness directives generally can lead to severe consequences. These may include grounding of the aircraft until compliance is achieved, fines, and potential criminal charges against responsible individuals or entities. Additionally, operators may face civil liabilities in the event of accidents or incidents resulting from non-compliance, which can include compensation for damages and legal costs. In summary, operators of the Eurocopter AS 355 (Twin Ecureuil) Series Helicopters must ensure their engine fire extinguishing systems conform to the specifications outlined in AS355 SB 2601 Revision 2 Figure 5. Compliance must be achieved within a specified timeframe to ensure the safety and airworthiness of the aircraft. Non-compliance can lead to severe penalties, including the potential grounding of the aircraft and legal consequences.