AD/EMB-120/2 - APU Electronic Control Unit

Overview

The Embraer EMB-120 (Brasilia) Series Aeroplanes Airworthiness Directive (AD/EMB-120/2), enacted under the Civil Aviation Regulations 1998, addresses the potential safety risk posed by the Auxiliary Power Unit (APU) Electronic Control Unit in Embraer 120 aircraft. The Australian Civil Aviation Safety Authority (CASA) issued this directive to ensure compliance with the technical requirements set forth by Brazilian AD 90-09-02 R1 dated 14 January 1991. The primary concern addressed by this legislation is the risk of accidental water contamination of the APU Electronic Control Unit during aircraft washing, which could lead to a malfunction in the APU overspeed control, thereby compromising flight safety. The directive mandates actions in accordance with the specified requirements to mitigate this identified safety hazard. This legislative instrument was introduced to ensure that all Embraer 120 aircraft conform to the necessary safety standards to prevent potential APU malfunctions that could endanger flight safety. By aligning with the Brazilian AD 90-09-02 R1, CASA aims to uphold stringent safety protocols and maintain the airworthiness of Embraer 120 aircraft operating within Australian airspace. The policy objective is to protect public safety by ensuring that aircraft meet the highest safety standards, thereby reducing the risk of in-flight emergencies due to APU failures.

Scope and Application

The Embraer EMB-120 (Brasilia) Series Aeroplanes Airworthiness Directive (AD) applies to all Embraer 120 aircraft as detailed in the Requirement Document. The directive mandates action in accordance with the technical requirements of Brazilian AD 90-09-02 R1 dated 14 January 1991, referencing Embraer Service Bulletin NR 120-053-0049. The directive requires compliance with the specified technical requirements as outlined in the Requirement Document, effective from 18 April 1991. The directive aims to address a safety concern where the Auxiliary Power Unit (APU) Electronic Control Unit may be accidentally contaminated with water during aircraft washing, leading to potential malfunction of the APU overspeed control, which could adversely affect flight safety. This legislative instrument operates under the jurisdiction of the Civil Aviation Safety Authority and extends its reach to ensure the maintenance of airworthiness standards for Embraer 120 series aeroplanes in Australia.

Key Provisions

The main operative sections of the Civil Aviation Regulations 1998, specifically Part 39 - 105, address the applicability and requirements of Airworthiness Directives (ADs) for the Embraer EMB-120 (Brasilia) Series Aeroplanes (section 39.105). This regulation mandates that all Embraer 120 aircraft must adhere to the technical requirements outlined in the Brazilian AD 90-09-02 R1 dated 14 January 1991. The directive emphasises compliance with the detailed requirements specified in the accompanying Requirement Document, which has an effective date of 18 April 1991. Embraer's Service Bulletin (SB) NR 120-053-0049 also references this directive, reinforcing its importance for maintaining aircraft airworthiness. The obligations imposed by this regulation on the parties or entities it governs include ensuring that all Embraer 120 aircraft undergo the specified actions in accordance with the AD. This includes the necessary modifications or inspections to address potential water contamination of the APU Electronic Control Unit, which can occur during aircraft washing. The directive necessitates that these modifications be implemented to prevent malfunctions of the APU overspeed control, thereby maintaining the safety of flight. The Requirement Document provides detailed instructions on how these actions must be carried out, ensuring a consistent and effective approach across all affected aircraft. Failure to comply with the AD may result in serious safety risks, potentially leading to civil or criminal consequences. While the specific penalties are not detailed in the excerpt provided, the Civil Aviation Regulations generally allow for substantial fines and other penalties for non-compliance with airworthiness directives. Such breaches can also result in the grounding of the aircraft until the required actions are completed, which can have significant operational and financial implications for the aircraft operators. Ensuring compliance is therefore critical to avoid these adverse outcomes.