COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bell Helicopter Textron 412 Series Helicopters
AD/BELL 412/19 Emergency DC Bus Number One Feeder Circuit 3/88
Applicability: All model Bell 412 and 412NB helicopters S/No 33108 to 33139 inclusive, and 33150 to 33154 inclusive.
Requirement: Action in accordance with Bell ASB 412-87-33 dated 1 December 1987.
Compliance: Within 100 hours time in service after 24 March 1988, or at the next scheduled inspection for Maintenance Release issue after 24 March 1988 whichever is the latter.
Background: Bell have advised that Model 412 emergency and essential buses are configured such that a short circuit on essential bus number 2 will cause both emergency bus 50 amp feeder circuit breakers to open thus removing all power from the emergency bus.
Overview
The Civil Aviation Regulations 1998, enacted by the Australian Parliament, govern the safety and operation of civil aviation in Australia, with the overarching aim of protecting public safety. Among these regulations, Part 39 focuses on specific airworthiness directives that ensure aircraft maintain a certain standard of safety. One such directive, AD/BELL 412/19, was introduced to address a specific issue with Bell Helicopter Textron 412 Series helicopters, specifically targeting models with serial numbers between 33108 to 33139 and 33150 to 33154. The problem this directive seeks to resolve is a potential electrical fault where a short circuit on the essential bus number 2 can inadvertently cut power to the emergency DC bus, compromising the helicopter’s emergency power supply. The directive mandates that corrective actions be taken in accordance with Bell ASB 412-87-33 dated 1 December 1987, within 100 hours of service time after 24 March 1988 or at the next scheduled inspection, whichever is later. This requirement aims to ensure the continued airworthiness and safety of the affected aircraft.
Scope and Application
The Civil Aviation Regulations 1998, specifically PART 39 - 105, pertains to the maintenance and airworthiness directives for aircraft in Australia, issued by the Civil Aviation Safety Authority (CASA). This regulation applies directly to all model Bell 412 and 412NB helicopters with serial numbers ranging from 33108 to 33139 inclusive, and from 33150 to 33154 inclusive. The requirement under this legislation mandates compliance with Bell ASB 412-87-33 dated 1 December 1987, which must be adhered to within 100 hours of the helicopter's time in service after 24 March 1988, or at the next scheduled inspection for Maintenance Release issue following that date, whichever occurs later. The directive aims to ensure the safety and operational integrity of the emergency DC bus number one feeder circuit in the specified helicopter models. This regulation extends its jurisdictional reach across the entire Commonwealth of Australia, ensuring uniform compliance and safety standards across all states and territories. The regulation does not specify any exclusions or exemptions but requires strict adherence to the outlined directives to maintain the airworthiness of the affected aircraft.
Key Provisions
The Civil Aviation Regulations 1998, under Part 39 - 105, specify certain airworthiness directives that must be followed to ensure the safety of aviation operations. One such directive, AD/BELL 412/19, pertains specifically to the Bell Helicopter Textron 412 Series Helicopters. This directive mandates actions to be taken concerning the Emergency DC Bus Number One Feeder Circuit for specific serial numbers of the Bell 412 and 412NB helicopters. Specifically, it applies to helicopters with serial numbers ranging from 33108 to 33139 inclusive, and 33150 to 33154 inclusive. The directive requires compliance with Bell ASB 412-87-33 dated 1 December 1987. Operators must ensure that the specified action is carried out within 100 hours of time in service after 24 March 1988, or at the next scheduled inspection for Maintenance Release issue following that date, whichever comes later.
The obligations imposed by this directive are clear and require operators of the affected helicopters to adhere to the specified maintenance action. The directive requires operators to follow the instructions outlined in Bell ASB 412-87-33, which includes detailed steps to address the potential short circuit issue that could result in the loss of power to the emergency bus. This requirement is designed to prevent operational disruptions and ensure the continued safety of the aircraft by maintaining the integrity of the emergency power system.
Failure to comply with the provisions of AD/BELL 412/19 may result in severe consequences. The Civil Aviation Safety Authority (CASA) can impose penalties for non-compliance with airworthiness directives, which can include fines and other regulatory actions. Additionally, operating a helicopter that does not meet the specified airworthiness standards can lead to severe safety risks, potentially resulting in accidents or incidents that could endanger lives. It is imperative that operators follow these directives to avoid these potential legal and safety repercussions.