COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Electrical Equipment
AD/ELECT/11 Leach Relays - Control Terminal Insulation NK
Applicability: All Leach type 5038, 5039, 5058, 5059, 5060, 5061 relays.
Requirement: Modify relays by increasing the insulation between the coil terminals and both the main contactor bar and the earthed metal yoke of the coil.
An approved method of compliance is as follows:
- Remove the two coil terminal screw assemblies.
2. Form a piece of 3 in. x 3 in. fibrous insulating sheet of 0.015 inch minimum thickness into a hat section so that the hollow portion can fit over the existing insulated terminal strip, with the remaining portions bearing against the moulded cover and the metal yoke respectively, so as to provide an equal overhang of insulation at each end of the terminal strip. Cut a suitable hole to permit the passage of the coil end wires through the new insulation and cut appropriate holes in the hat section to correspond with the existing holes in the terminal strip. Varnish the formed strip.
3. Place the completed hat section in position and pass the coil wires through the appropriate hole. Replace the coil terminal assemblies at the same time connecting up the coil wires and clamping the new insulation firmly in place on each side of the terminal strip; or
ANO 107.2.6.2.1.
Compliance: Before installation in an aircraft.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), were enacted to ensure the safe operation of aircraft within Australian airspace. This legislation forms part of the broader framework aimed at maintaining high standards of aviation safety, addressing potential risks and ensuring compliance with international aviation standards. The specific Airworthiness Directive AD/ELECT/11 concerning Leach Relays - Control Terminal Insulation, was introduced to mitigate risks associated with inadequate insulation in certain types of electrical relays, thereby enhancing the safety and reliability of aircraft electrical systems. The policy objective is to prevent electrical faults that could compromise flight safety by ensuring that the insulation between relay terminals and other conductive parts meets specified standards. The directive applies to all Leach type 5038, 5039, 5058, 5059, 5060, and 5061 relays, requiring modifications to increase the insulation thickness and specifying an approved method for compliance.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39, mandates the application of Airworthiness Directives concerning the electrical equipment of aircraft, including Leach relays. The regulation applies to all aircraft equipped with Leach type 5038, 5039, 5058, 5059, 5060, and 5061 relays, requiring modifications to increase the insulation between the coil terminals and both the main contactor bar and the earthed metal yoke of the coil. This directive is pertinent to all aircraft operators and maintenance personnel within the Commonwealth of Australia, ensuring compliance with the specified safety standards. The regulation does not explicitly state any exclusions or exemptions, and its jurisdictional reach is confined to the national airspace governed by Australian civil aviation authorities. Compliance is enforced before installation in any aircraft, ensuring that any modifications are made prior to the aircraft being returned to service.
Key Provisions
The Civil Aviation Regulations 1998, particularly Part 39 - 107, includes specific directives for ensuring the airworthiness of electrical equipment in aircraft. One such directive, AD/ELECT/11, pertains to Leach Relays - Control Terminal Insulation (sections referenced are 107.2.6.2.1). This directive applies to all Leach type 5038, 5039, 5058, 5059, 5060, and 5061 relays. The key requirement is to modify these relays by increasing the insulation between the coil terminals and both the main contactor bar and the earthed metal yoke of the coil to enhance safety.
To comply with AD/ELECT/11, an approved method involves several steps. Firstly, the two coil terminal screw assemblies must be removed. Secondly, a piece of fibrous insulating sheet, measuring at least 3 inches by 3 inches and with a minimum thickness of 0.015 inches, should be formed into a hat section. This section must fit over the existing insulated terminal strip, providing an equal overhang of insulation at each end of the terminal strip. Holes must be cut to allow the coil end wires to pass through the new insulation and corresponding holes must be made in the hat section to align with the existing holes in the terminal strip. The formed strip should then be varnished.
Once the hat section is ready, it should be placed in position and the coil wires passed through the appropriate hole. The coil terminal assemblies should then be replaced while connecting the coil wires and ensuring the new insulation is firmly clamped in place on each side of the terminal strip. This method ensures that the insulation is properly installed before the relay is returned to service, as required by the regulation.
The obligations imposed by this directive are clear: all affected parties must ensure that the specified modifications are carried out on the relays before they are installed in an aircraft. Failure to comply with these requirements can lead to serious safety issues and potential non-compliance with civil aviation regulations. Any breach of this directive could result in severe consequences, including the grounding of the aircraft until the modifications are correctly implemented, as well as potential civil or criminal penalties for those responsible for the oversight.