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/F50/34 Electrical Power - AC Emergency Inverter 4/90
Applicability: All F27 Mk50 aircraft S/Nos 20103 to 20161 inclusive. Requirement: Action in accordance with Fokker SB F50-24-009 or later revision.
Note: RLD Airworthiness Directive BLA 90-003 also refers.
Compliance: Prior to 19 January 1991.
Background: When the AC Power is switched from NORMAL to EMERGENCY, the attitude and heading reference system (AHRS) does not work for approximately 45 seconds, due to a combination of tolerances built into the emergency inverter and the AHRS. This Airworthiness Directive calls for a wiring change to the circuit of the emergency inverter. The emergency inverter will now be switched ON from the standby mode. This will make sure that the AHRS does not become inoperative when the AC power is switched from normal to emergency.
Overview
The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia, form a crucial part of the legislative framework governing aviation safety within the country. One specific legislative instrument under these regulations, identified as F2006B09861, addresses a particular safety concern related to the Fokker F50 (F27 Mk 50) series aeroplanes. This instrument, an Airworthiness Directive (AD), specifically mandates action to resolve an issue with the electrical power system in these aircraft. The directive was introduced to address a problem where the attitude and heading reference system (AHRS) would become inoperative for approximately 45 seconds when the AC power was switched from normal to emergency mode. This lapse in functionality could potentially compromise the safety and control of the aircraft during critical phases of flight. The directive requires compliance with Fokker Service Bulletin F50-24-009 or later revisions, ensuring that the emergency inverter is properly configured to prevent the AHRS from becoming inoperative during power transitions. The directive aims to maintain the highest standards of aviation safety by mitigating risks associated with this identified issue.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to Airworthiness Directives for particular aircraft models, including Fokker F50 (F27 Mk 50) series aeroplanes, and applies to all aircraft within the specified serial number range. This legislative instrument ensures that these aircraft meet specific safety standards and operational requirements. The geographic reach of these regulations is national, as they apply across Australia under the Commonwealth's jurisdiction. The directive mandates compliance with Fokker Service Bulletin F50-24-009 or any subsequent revisions to address an issue where the attitude and heading reference system (AHRS) becomes temporarily inoperative during a switch from normal to emergency AC power. Compliance with this directive must be achieved prior to 19 January 1991. Any non-compliance could potentially lead to safety risks during flight operations. The regulations do not explicitly mention any exclusions or exemptions, and adherence is mandatory for all specified aircraft within the operational fleet.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 105, includes an Airworthiness Directive (AD) concerning Fokker F50 (F27 Mk 50) series aeroplanes. This directive, known as AD/F50/34, pertains to the electrical power systems, more precisely the AC Emergency Inverter, for aircraft serial numbers 20103 to 20161. It requires compliance with Fokker Service Bulletin F50-24-009 or any subsequent revisions. Furthermore, it references RLD Airworthiness Directive BLA 90-003. The directive mandates adherence to these standards before 19 January 1991.
The AD/F50/34 imposes specific obligations on the operators of the Fokker F50 series aeroplanes covered by this directive. Primarily, it mandates that these operators must implement the wiring changes to the emergency inverter circuit as outlined in Fokker SB F50-24-009 or any later revisions. This is to ensure that the attitude and heading reference system (AHRS) does not become inoperative during a switch from normal AC power to emergency power, which previously resulted in the AHRS being inoperative for approximately 45 seconds. The directive ensures that the emergency inverter is switched on from standby mode, thereby maintaining the AHRS functionality during such transitions.
Failure to comply with the requirements set out in AD/F50/34 can result in significant consequences. The Civil Aviation Regulations 1998 outline potential penalties for non-compliance with airworthiness directives. While specific penalties are not detailed in the directive itself, non-compliance generally can lead to enforcement actions under the Civil Aviation Act 1988. These actions can include fines, operational restrictions, or other regulatory measures intended to ensure compliance with airworthiness standards. The exact penalties would depend on the severity of the non-compliance and any resultant safety risks.