COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Fokker F50 (F27 Mk 50) Series Aeroplanes
AD/F50/43 Fuselage - Flight Compartment Window Frames -1 9/91
Applicability: All F50 aircraft. Serial numbers 20103 to 20108 inclusive and 20110 to 20122 inclusive.
Requirement: Action in accordance with the Technical Requirements of Netherlands AD BLA 89-98, dated 25 August 1989.
Compliance: Prior to accumulating 10,000 pressurization cycles.
Background: During full-scale fatigue tests of the forward fuselage test article, cracks occurred on the outside edges of the flight compartment window frames. These edges are sharp, which creates local stress concentrations. This AD calls for reworking of the outside edges of the flight-compartment window-frames to introduce a 0.5 mm radius.
Overview
The Civil Aviation Regulations 1998, amended by the Legislative Instrument F2006B09870, introduces specific Airworthiness Directives concerning Fokker F50 (F27 Mk 50) Series Aeroplanes. This legislative instrument was enacted to address safety concerns identified during fatigue tests, specifically the occurrence of cracks on the outside edges of the flight compartment window frames. The problem was that these sharp edges led to local stress concentrations, which could potentially compromise the structural integrity of the aircraft. The policy objective of this directive is to ensure the safety and airworthiness of these aircraft by requiring the reworking of the window frames to mitigate these stress concentrations. This directive is enforced by the Civil Aviation Safety Authority and applies to all Fokker F50 aircraft within the specified serial number ranges, mandating compliance before the aircraft accumulates 10,000 pressurization cycles.
The directive is aligned with the technical requirements outlined in the Netherlands AD BLA 89-98, dated 25 August 1989, which mandates the introduction of a 0.5 mm radius on the outside edges of the flight compartment window frames. This action is crucial for preventing the development of cracks and ensuring the longevity and safety of the aircraft in service. The requirement is enforced to maintain the high safety standards set by the Civil Aviation Safety Authority, ensuring that all Fokker F50 aircraft meet the necessary airworthiness criteria before they continue to operate.
Scope and Application
The Civil Aviation Regulations 1998, as amended, under the authority of the Civil Aviation Safety Authority, mandate the application of Airworthiness Directives to ensure the safe operation of aircraft within Australian airspace. Specifically, AD/F50/43 pertains to Fokker F50 (F27 Mk 50) series aeroplanes, targeting the fuselage flight compartment window frames. This directive applies to all F50 aircraft with serial numbers ranging from 20103 to 20108 inclusive and from 20110 to 20122 inclusive. The requirement is to conform to the technical specifications outlined in the Netherlands AD BLA 89-98, dated 25 August 1989, which involves modifying the window frames to mitigate the risk of stress-induced cracks. Compliance is mandatory before the aircraft accumulates 10,000 pressurization cycles, ensuring that the structural integrity of the window frames is maintained throughout the aircraft's operational life. The directive applies nationally, and while the scope is limited to specific Fokker F50 aircraft, the regulation's intent is to enhance the safety of all civil aviation operations within Australia.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes Airworthiness Directives (AD) issued to ensure the safety and airworthiness of aircraft. Section AD/F50/43 pertains to the Fokker F50 (F27 Mk 50) Series Aeroplanes, focusing on fuselage flight compartment window frames. This AD applies to all F50 aircraft with serial numbers ranging from 20103 to 20108 inclusive and 20110 to 20122 inclusive (AD/F50/43, Applicability). The directive requires that these aircraft undergo specific modifications to the flight compartment window frames to address identified safety concerns. The required action is detailed in the Technical Requirements of Netherlands AD BLA 89-98, dated 25 August 1989 (AD/F50/43, Requirement).
Operators of the affected F50 aircraft must comply with this directive by ensuring that the modifications are completed before the aircraft accumulates 10,000 pressurization cycles (AD/F50/43, Compliance). The modifications are necessary to mitigate the risk of cracks occurring on the outside edges of the flight compartment window frames, which can lead to sharp edges and local stress concentrations. These stress concentrations can potentially compromise the structural integrity of the aircraft, posing a risk to flight safety. To address this, the AD mandates the reworking of the outside edges of the flight-compartment window-frames to introduce a 0.5 mm radius, thereby reducing the potential for stress concentration and associated structural issues (AD/F50/43, Requirement).
Failure to comply with this directive can result in significant legal and safety consequences. Operators must ensure that the specified modifications are carried out as required. Non-compliance with AD/F50/43 could lead to the aircraft being deemed unairworthy, which could result in grounding of the aircraft until the required modifications are completed. Additionally, non-compliance with airworthiness directives can lead to enforcement actions by the Civil Aviation Safety Authority (CASA), which may include fines, enforcement notices, or other regulatory measures. The severity of the consequences underscores the importance of adhering to the specified requirements to maintain the airworthiness of the aircraft and ensure the safety of all onboard.