AD/F50/59 - Engine Electronic Control System

Overview

The Civil Aviation Regulations 1998, which form a part of the overarching framework governing civil aviation safety in Australia, were enacted to ensure the safety and efficiency of air travel. Among the various provisions, Part 39 - 105 specifically addresses the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, which includes critical safety measures for different types of aircraft. One such directive, AD/F50/59, pertains to Fokker F50 (F27 Mk 50) series aeroplanes, specifically addressing the engine electronic control system. This directive was introduced to rectify a safety issue where an engine electronic control failure would cause the affected engine fuel control to remain at the last selected power setting, resulting in a lack of power response when the power levers are manipulated unless manual mode is selected by the pilot. The policy objective is to enhance the safety of Fokker F50 aircraft by requiring the replacement of the EEC with a modified version that automatically selects manual mode in the event of an EEC failure below a specified power lever angle. The directive applies to Fokker F27 Mk 050 aircraft with serial numbers ranging from 20103 to 202427 inclusive, necessitating compliance with Fokker Service Bulletin F50-73-013 and Component Service Bulletin F7941-006-73-03, as well as RLD Airworthiness Directive BLA 92-086. This directive was issued to ensure that all affected aircraft meet the required safety standards before 4 February 1994. The enacting body responsible for these regulations is the Australian Government, specifically the Civil Aviation Safety Authority, under the authority granted by the Civil Aviation Act 1988.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, governs the operational standards of Fokker F50 (F27 Mk 50) series aeroplanes. This legislation applies to Fokker F50 aircraft with serial numbers ranging from 20103 to 202427 inclusive. The directive mandates compliance with Fokker Service Bulletin F50-73-013 dated 6 July 1992, and references Fokker Component Service Bulletin F7941-006-73-03, as well as RLD Airworthiness Directive BLA 92-086 dated 18 September 1992. The requirement necessitates replacing the engine electronic control system to ensure that in the event of an EEC failure, manual mode is automatically selected if the power lever angle is below 17 degrees, ensuring power response from the affected engine. Compliance with these directives must be achieved prior to 4 February 1994 to maintain the airworthiness of the specified Fokker F50 series aircraft.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105, which pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, includes a specific directive for Fokker F50 (F27 Mk 50) Series Aeroplanes. This directive, identified as AD/F50/59, focuses on the engine electronic control (EEC) system (Section 1). The directive applies to F27 Mk 050 aircraft with serial numbers ranging from 20103 to 202427 inclusive (Section 2). The primary requirement outlined in this directive is the replacement of the existing EEC with a modified version as specified in Fokker Service Bulletin F50-73-013 dated 6 July 1992 (Section 3). Additionally, Fokker Component Service Bulletin F7941-006-73-03 is referenced for further guidance, and RLD Airworthiness Directive BLA 92-086 dated 18 September 1992 also pertains to this matter (Section 4). The compliance deadline for this directive is set for 4 February 1994 (Section 5). The obligations imposed by this directive are specific and clear. Operators of the affected Fokker F50 aircraft must ensure that the EEC system is replaced with the modified version specified in the referenced service bulletins. This requirement is not merely advisory but mandatory, as it is part of the Civil Aviation Regulations. The modified EEC system is designed to automatically select manual mode if an EEC failure occurs below the 17 degrees power lever angle, which is the approach position. This change is crucial to ensure the safety of the aircraft during critical phases of flight (Section 6). The directive underscores the importance of maintaining airworthiness by addressing a specific vulnerability in the engine control system. Failure to comply with this directive can result in serious consequences. The Civil Aviation Regulations do not explicitly detail penalties in the provided text, but non-compliance with airworthiness directives is generally considered a serious breach that can lead to severe civil or criminal penalties. This could include fines, suspension or revocation of the aircraft's certificate of airworthiness, and potential criminal charges against the operator or responsible individuals. Such penalties are intended to enforce the high standards of safety required in civil aviation (Section 7). The potential severity of the consequences underscores the importance of adhering to the directive within the specified timeframe.