AD/F50/32 Amdt 1 - Electrical Power - Terminal Block and Contactor Torque Values

Overview

The Civil Aviation Regulations 1998, amended through the Legislative Instrument F2006B09859, addresses specific safety concerns related to Fokker F50 (F27 Mk 50) series aeroplanes. Enacted by the Australian Government, the Civil Aviation Safety Authority issued this Airworthiness Directive to mitigate risks associated with improperly tightened terminal blocks and contactors in the electrical power centre and relay panel, which could lead to overheating and potential fires. This directive specifically applies to Fokker F50 aircraft within the serial number ranges identified, requiring compliance with Fokker Service Bulletin F50-24-A013 Revision 2 or later, ensuring that the aircraft meet stringent safety standards to prevent incidents similar to a recent event on a Fokker 100 where smoke was observed on the flight deck due to a similar issue. The policy objective is to enhance the safety and reliability of these aircraft by standardising maintenance practices and ensuring all electrical connections are properly secured.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, govern the airworthiness directives that apply to Fokker F50 (F27 Mk 50) series aeroplanes, including the AD/F50/32 Amendment 1, which addresses electrical power - terminal block and contactor torque values. This legislation applies to all F27 Mk50 aircraft with specific serial numbers: 20103 to 20108; 20110 to 20169, 20171, and 20172. The requirement mandates action in accordance with Fokker Service Bulletin F50-24-A013 Revision 2 or later, referencing RLD Airworthiness Directive BLA 89-159 Issue 2. Compliance with these directives must be achieved before 21 January 1990, following an incident where smoke on the flight deck during approach of a Fokker 100 was attributed to an improperly tightened terminal on a generator line contactor in the electrical power centre, leading to excessive heat and partial melting of the EPC. This Airworthiness Directive necessitates the inspection and adjustment of torque values on terminal blocks and contactors in the EPC and relay panel in the forward cargo compartment to prevent similar incidents on Fokker 50 aircraft.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates the adherence to airworthiness directives for certain aircraft models, including the Fokker F50 (F27 Mk 50) series aeroplanes. Section AD/F50/32 Amendment 1 pertains to the electrical power system of these aircraft, particularly focusing on the terminal block and contactor torque values. The directive applies to Fokker F50 aircraft with serial numbers ranging from 20103 to 20108, 20110 to 20169, and 20171 and 20172 (paragraph 1). Compliance with this directive requires actions to be taken in accordance with Fokker Service Bulletin F50-24-A013 Revision 2 or later (paragraph 2). This is to ensure the safety of the aircraft's electrical systems, which were found to have improperly tightened terminals that could cause overheating and potential fire hazards. The obligations under this directive are clear: aircraft owners and operators must ensure that the terminal blocks and contactors in the electrical power centre (EPC) and on the relay panel in the forward cargo compartment are inspected and adjusted as per the specified service bulletin. This is to prevent similar incidents to the one that occurred on a Fokker 100, where smoke on the flight deck during approach was attributed to an improperly tightened terminal on a generator line contactor (GLC) (paragraph 3). The compliance date for these measures is set before 21 January 1990, which means that any non-compliance could result in serious safety implications for the affected aircraft. The legislation does not explicitly outline offences, penalties, or consequences for breach in the provided text. However, it is implied that failure to comply with airworthiness directives can lead to significant safety risks, which may be subject to enforcement actions by the Civil Aviation Safety Authority (CASA). Given the potential for serious incidents, such as the one that occurred on the Fokker 100, non-compliance could result in severe consequences, including grounding of the aircraft, fines, or other regulatory penalties. The precise penalties would depend on the severity of the breach and the specific provisions of the Civil Aviation Act 1988 and associated regulations.