AD/AS 355/35 - AC Generation System

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, form a comprehensive regulatory framework governing civil aviation within the country. This legislation, under Part 39 - 105, introduces specific airworthiness directives to ensure the safety and compliance of aircraft operations. One such directive, AD/AS 355/35, pertains to Eurocopter AS 355 (Twin Ecureuil) Series Helicopters, addressing a critical issue with the AC generation system in certain models. The directive was introduced to mitigate the risk of total AC power loss due to a diode mounting fault on specific printed circuit boards, ensuring the safety of these aircraft in both Instrument Flight Rules (IFR) and Visual Flight Rules (VFR) conditions. The policy objective is to maintain and enhance the safety standards of civil aviation by enforcing rigorous compliance measures on aircraft maintenance and operations. The directive mandates compliance with work card No 24.22.04.501 (updated 83.31), requiring the correct operation of the AC power system and inspection of replacement parts before installation. This measure aims to prevent potential power failures that could compromise flight safety. The directive applies to all Aerospatiale AS 355E, F, F1, F2, and N series helicopters equipped with dual AC generation systems, delivered before 5 April 1990. Compliance must be achieved either before the next scheduled flight under IFR conditions, for VFR operations within 100 hours of service after 2 May 1990, or prior to fitting any replacement printed circuit board not bearing the inspection stamp SS 235. This legislative instrument underscores the commitment to ensuring the highest safety standards in civil aviation.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to airworthiness directives for certain aircraft, including the Eurocopter AS 355 (Twin Ecureuil) series helicopters. This legislation applies to all Aerospatiale AS 355E, F, F1, F2, and N series helicopters equipped with dual AC generation systems that were delivered prior to 5 April 1990. The directive mandates that the aircraft's AC power system must operate correctly in accordance with the specified work card, No 24.22.04.501 (updated 83.31), and references Aerospatiale Service Telex 01.29 for additional information. Compliance with these regulations requires the aircraft to meet certain conditions before the next flight under Instrument Flight Rules (IFR), or within 100 hours of time in service after 2 May 1990 for aircraft operated under Visual Flight Rules (VFR). Additionally, if a replacement printed circuit board 3 x 1 or 3 x 2 is to be fitted and does not bear the required inspection stamp SS 235, it must be inspected before installation. These regulations ensure the safety and airworthiness of the specified helicopters by addressing a known issue with the AC power system that could result in total power loss.

Key Provisions

The Civil Aviation Regulations 1998 (Regulations), specifically under PART 39 - 105, include the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives (AD). The directive AD/AS 355/35 pertains to Eurocopter AS 355 (Twin Ecureuil) series helicopters, which are Aerospatiale AS 355E, F, F1, F2, and N series helicopters equipped with dual AC generation systems delivered before 5 April 1990 (Section 1). The directive mandates ensuring the correct operation of the AC power system in accordance with work card No 24.22.04.501 (updated 83.31), and it references Aerospatiale Service Telex 01.29 for further details (Section 2). Compliance with this directive is required under specific conditions: either prior to the next flight scheduled under Instrument Flight Rules (IFR) conditions or, for aircraft operated under Visual Flight Rules (VFR) conditions, prior to 100 hours of time in service after 2 May 1990 (Section 3). Additionally, if a printed circuit board 3 x 1 or 3 x 2 is to be fitted as a replacement part and does not bear the inspection stamp "SS 235," it must be fitted before it is put into service (Section 4). The obligations imposed by this directive on the operators of the specified helicopters are to ensure that the AC power system is functioning correctly as per the outlined work card and referenced telex. Operators must comply with the specified timelines for checks and maintenance: before the next IFR flight or before 100 hours of VFR flight time post-2 May 1990, whichever is applicable. Moreover, if any replacement printed circuit boards are to be installed, they must have the correct inspection stamp "SS 235" before being fit to the aircraft. Failure to adhere to these requirements can result in non-compliance with the regulatory standards set by CASA, potentially leading to the grounding of the aircraft until the required checks and maintenance are satisfactorily completed. Failure to comply with the provisions of AD/AS 355/35 could result in significant civil and criminal consequences. Civil Aviation Regulations 1998 outline penalties for non-compliance with ADs, which can include fines and other civil penalties. The exact penalties are not specified in the directive but typically involve significant financial repercussions for the non-compliant party. Furthermore, operating an aircraft that does not comply with airworthiness directives can lead to criminal charges under the Civil Aviation Act 1988, which may result in imprisonment or fines depending on the severity of the breach. The specific penalties can vary based on the nature and extent of the non-compliance but are designed to ensure strict adherence to safety regulations to prevent potential hazards such as total loss of AC power.