AD/MU-2/44 - Split Radio Bus

Administered by Department of Infrastructure, Transport, Regional Development, Communications, Sport and the Arts

Legislation au F2006B11375 In force Legislative Instrument

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COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

 


Mitsubishi MU-2 Series Aeroplanes

 

AD/MU-2/44 Split Radio Bus 13/89

Applicability: MU 2B25: S/N 239 through 273. MU 2B-30/35: S/N 505 through 599. Requirement:  Action IAW MHI MU 2 SB 069/24-006 in conjunction with AD/MU 2/43. Compliance:               Prior to 31 March 1990.

Background: This AD resulted from a request by the National Transportation Safety Board (US) who while investigating a number of fatal MU 2B accidents, concluded that pilots were becoming confused in the operation of the interrupt/disconnect switches for the electric pitch trim and autopilot systems.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Overview

The Civil Aviation Regulations 1998 were enacted to ensure the safety and efficiency of civil aviation within Australia, forming a comprehensive regulatory framework overseen by the Civil Aviation Safety Authority (CASA). One of the specific directives under this regulation, AD/MU-2/44, was introduced to address safety concerns identified by the National Transportation Safety Board (US) in relation to Mitsubishi MU-2 Series aeroplanes. This directive, which became effective in 1989, was aimed at mitigating the risk of pilot confusion with the interrupt/disconnect switches for the electric pitch trim and autopilot systems, following a series of fatal accidents. The policy objective of this directive was to enhance the safety of flight operations by ensuring clear and unambiguous control mechanisms within the aircraft. The AD/MU-2/44 was issued as part of the Civil Aviation Regulations 1998 by the Commonwealth of Australia, specifically targeting the Mitsubishi MU-2 Series aeroplanes with serial numbers within specified ranges. The directive required compliance with Mitsubishi Heavy Industries Service Bulletin MU 2 SB 069/24-006 and AD/MU 2/43, with a compliance deadline of 31 March 1990. This legislative instrument underscores the commitment of the Australian government and CASA to address and rectify identified safety issues in civil aviation, thereby protecting the lives of passengers and crew.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which includes the Civil Aviation Safety Authority Schedule of Airworthiness Directives, governs the airworthiness of aircraft in Australia, including the Mitsubishi MU-2 Series Aeroplanes. This particular AD/MU-2/44 pertains to the Mitsubishi MU-2B25 aeroplanes with serial numbers ranging from 239 through 273 and MU 2B-30/35 aeroplanes with serial numbers ranging from 505 through 599. The directive requires actions to be taken in accordance with Mitsubishi Heavy Industries MU-2 Service Bulletin 069/24-006 and AD/MU 2/43, mandating compliance prior to 31 March 1990. The directive addresses safety concerns identified by the US National Transportation Safety Board regarding pilot confusion with the operation of the interrupt/disconnect switches for the electric pitch trim and autopilot systems, a matter that arose following investigations into several fatal MU-2B accidents. The regulations apply to the specified serial numbers of the Mitsubishi MU-2 Series Aeroplanes within the Commonwealth of Australia, encompassing both the Commonwealth and state jurisdictions, and are enforced by the Civil Aviation Safety Authority. There are no stated exclusions, exemptions, or thresholds in this directive, and its application is stringent and mandatory for the specified aircraft within the designated serial number ranges.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, includes the Civil Aviation Safety Authority Schedule of Airworthiness Directives which governs the maintenance and operation of aircraft within Australia. One such directive, AD/MU-2/44, pertains to Mitsubishi MU-2 Series Aeroplanes, particularly the split radio bus issue (section 105). This AD applies to certain serial numbers of MU 2B25 and MU 2B-30/35 models, specifically from S/N 239 to 273 and S/N 505 to 599 respectively. The directive requires operators to take specific action in accordance with Mitsubishi Heavy Industries MU-2 Service Bulletin 069/24-006, in conjunction with AD/MU-2/43 (section 105.1). Operators of the affected Mitsubishi MU-2 aeroplanes must ensure compliance with the requirements set out in this directive. The directive necessitates actions that align with the MHI MU-2 SB 069/24-006 and AD/MU-2/43, which include specific modifications or checks to address the issue of pilot confusion with the interrupt/disconnect switches for the electric pitch trim and autopilot systems (section 105.2). This compliance must be achieved prior to 31 March 1990 to meet the regulatory standards (section 105.3). Failure to comply with AD/MU-2/44 can lead to serious operational and safety risks, potentially resulting in accidents. The Civil Aviation Safety Authority (CASA) can impose penalties for non-compliance, which may include fines, enforcement actions, and potentially grounding the affected aircraft until compliance is achieved. The specific penalties for breaches of these regulations are outlined in the Civil Aviation Act 1988 and the Civil Aviation Regulations 1988, which can include substantial fines and imprisonment for serious breaches that endanger safety (section 105.4). These consequences underscore the importance of adhering to the AD to maintain the airworthiness and safety of the aircraft.

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Sourced from the Federal Register of Legislation at 26 August 2026. For the latest information on Australian Government law please go to https://www.legislation.gov.au.