COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Auxiliary Power Units
AD/APU/9 PW901A APU Idler Gear and Cooling Fan Shaft 10/93
Applicability: Pratt and Whitney Canada PW901A Auxiliary Power Units (APU) installed in, but not limited to, Boeing 747-400 series aircraft.
Requirement: Action in accordance with the requirements of Pratt and Whitney Canada Alert Service Bulletin Number A16159 Rev. 1.
Note: Transport Canada Airworthiness Directive CF-93-09 and FAA Airworthiness Directive T93-10-51 refer.
Compliance: Effective 16 September 1993: At the first main base transit check with an aircraft layover time exceeding 3 hours.
Background: This Directive has been issued to address a possible smoke in cabin situation. The requirement follows advice of two incidents in which, fracture of the PW901A APU idler gear and cooling fan shaft, resulted in debris flooding the load gearbox allowing oil to enter the load compressor air system.
Overview
The Civil Aviation Regulations 1998, specifically under PART 39 - 107, introduced the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives to ensure the continued airworthiness of aircraft. One such directive, AD/APU/9, pertains to the Pratt and Whitney Canada PW901A Auxiliary Power Units (APU) installed in various aircraft, including the Boeing 747-400 series. This legislation was enacted to address a critical safety concern identified through incidents where fractures in the APU idler gear and cooling fan shaft led to potential smoke in the cabin and other hazardous conditions. The directive mandates adherence to specific action requirements as outlined in Pratt and Whitney Canada Alert Service Bulletin Number A16159 Rev. 1, with cross-references to similar directives by Transport Canada and the Federal Aviation Administration (FAA). The directive aims to ensure compliance by requiring specific actions during the first main base transit check if the aircraft has a layover time exceeding three hours, effective from 16 September 1993.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 107, under the Civil Aviation Safety Authority, mandates the application of Airworthiness Directives (AD) concerning various components and systems of aircraft to ensure safe operations. In this context, AD/APU/9 pertains to Pratt and Whitney Canada PW901A Auxiliary Power Units (APU) installed in, but not limited to, Boeing 747-400 series aircraft. This regulation applies to any aircraft operator or maintenance provider who services or maintains such APUs. The requirement necessitates adherence to the actions specified in Pratt and Whitney Canada Alert Service Bulletin Number A16159 Rev. 1, which addresses a potential issue of smoke in the cabin due to a fracture in the APU idler gear and cooling fan shaft. The directive is in alignment with similar measures issued by Transport Canada and the Federal Aviation Administration of the United States. Compliance is mandatory from the date of issuance, specifically requiring action during the first main base transit check if the aircraft's layover time exceeds three hours. This ensures that the risk of cabin smoke due to oil entering the load compressor air system is mitigated effectively.
Key Provisions
The Civil Aviation Regulations 1998, specifically within Part 39, contains detailed provisions concerning airworthiness directives, among which is AD/APU/9 focusing on Pratt and Whitney Canada PW901A Auxiliary Power Units (APU) installed in certain aircraft. This directive (Section 10) applies to PW901A APUs in aircraft such as the Boeing 747-400 series. The requirement outlined in this directive mandates adherence to Pratt and Whitney Canada Alert Service Bulletin Number A16159 Rev. 1, ensuring that any actions taken comply with the specified guidelines to mitigate potential risks. This directive is cross-referenced with Transport Canada Airworthiness Directive CF-93-09 and FAA Airworthiness Directive T93-10-51, indicating a coordinated international response to the identified issue.
Entities governed by these regulations are obligated to ensure that the required actions are undertaken at the first main base transit check if the aircraft has a layover time exceeding three hours. This requirement was set to be effective as of 16 September 1993, and it is aimed at preventing possible smoke in the cabin caused by the fracture of the APU idler gear and cooling fan shaft, which could lead to oil entering the load compressor air system through the load gearbox. The directive addresses a critical safety concern that could potentially compromise the aircraft's operational safety and the safety of passengers and crew.
Failure to comply with the provisions set out in AD/APU/9 may result in severe consequences. The Civil Aviation Safety Authority (CASA) enforces strict adherence to these directives to maintain the highest safety standards. Any breaches of these regulations could potentially lead to serious civil or criminal penalties. While specific penalties are not detailed in the directive itself, non-compliance with airworthiness directives can typically result in fines, enforcement actions, and in extreme cases, grounding of the aircraft until compliance is achieved. These measures underscore the importance of adhering to the specified requirements to ensure the safety and airworthiness of the aircraft.