AD/RAD/36 Amdt 1 - Collins ADF Type ADF-650 - Operation From 27.5 Volt Supply

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, address the safety and operational standards for civil aviation within the country. This legislation was established to ensure the safety of air travel and to provide a regulatory framework governing the operation of aircraft. One particular aspect of this regulation is found in Part 39, which focuses on airworthiness directives concerning radio communication and navigation equipment. Specifically, AD/RAD/36 Amendment 1 pertains to the Collins ADF Type ADF-650, outlining the requirements for its operation from a 27.5 volt supply. The policy objective of this amendment is to rectify an issue identified with the voltage-dropping resistor used in the Collins RCR-650 receivers installed in aircraft with 27.5 volt electrical systems, which were found to have an inadequate power rating, leading to overheating. The amendment provides alternative solutions to ensure safe operation of the equipment.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, pertains to the operational requirements and safety measures concerning radio communication and navigation equipment in aircraft. The regulation AD/RAD/36 Amendment 1, focusing on Collins ADF Type ADF-650 receivers installed in aircraft with 27.5 volt electrical systems, applies directly to these receivers. The regulation mandates specific modifications to ensure the safe operation of these receivers, which were found to be inadequately powered by their original 11 ohm, 15 watt voltage-dropping resistors. The directive requires compliance within 100 hours after 30 November 1982, stipulating modifications to either update the equipment as per Collins RCR-650 receiver Service Information Letter 1-77 and Collins RCR-650 receiver Service Bulletin No. 3, install a higher power dropping resistor in a remote location, or modify the system wiring to incorporate a 28V/14V converter. This regulation applies nationally, overseen by the Commonwealth of Australia, and is applicable to all aircraft within the jurisdiction that have Collins RCR-650 receivers operating from a 27.5 volt supply.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 107, includes an Airworthiness Directive (AD) regarding the operation of Collins ADF Type ADF-650 receivers in aircraft with 27.5 volt electrical systems (AD/RAD/36/Amdt 1). This directive applies to Collins RCR-650 receivers installed in aircraft that operate on a 27.5 volt electrical system (Section 1). The directive mandates that these receivers must be modified to prevent overheating of the voltage-dropping resistor, which was originally specified as an 11 ohm, 15 watt type but is inadequately rated for the 27.5 volt supply (Section 2). To comply with the directive, operators must either modify the equipment as outlined in Collins RCR-650 receiver Service Information Letter 1-77 and Collins RCR-650 receiver SB No. 3, or install a dropping resistor and mounting hardware capable of adequate power dissipation, or modify the system wiring to provide operating power from a 28V/14V converter of an appropriate rating (Section 3). Any resistor used must be mounted in a remote location to prevent heat transfer to the avionics equipment (Section 3). Compliance with these modifications is required within 100 hours after 30 November 1982 (Section 4). Operators of aircraft with Collins RCR-650 receivers must ensure that any modifications or installations are carried out by qualified personnel in accordance with the manufacturer’s instructions or approved alternatives. The modifications must be logged in the aircraft maintenance records, and a certificate of compliance must be issued by the person performing the work, certifying that the modifications have been completed in accordance with the directive (Section 5). Additionally, operators must verify that all modifications have been properly completed and that the receivers are functioning correctly before further flight operations (Section 5). Failure to comply with this Airworthiness Directive may result in serious safety hazards, such as the failure of the ADF receiver, which can adversely affect the aircraft’s navigational capabilities. In the event of a non-compliance, the Civil Aviation Safety Authority (CASA) may take enforcement action against the operator. Possible consequences include fines, suspension or revocation of the aircraft’s certificate of airworthiness, and potential criminal charges against the operator or maintenance personnel involved (Section 6). The maximum penalties for such violations can include substantial fines and imprisonment for individuals, reflecting the serious nature of non-compliance with airworthiness directives (Section 7).