AD/AS 355/39 - Electric Hoist Installation

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of the Commonwealth of Australia, provide comprehensive safety regulations for civil aviation, including the operation of aircraft and maintenance directives. Part 39, which focuses on airworthiness directives, was introduced to address safety issues and ensure that aircraft meet required safety standards. Specifically, the directive for the Eurocopter AS 355 (Twin Ecureuil) Series Helicopters, identified as AD/AS 355/39, targets the installation of electric hoists to mitigate the risk of inadvertent pyrotechnic cable cuts. The policy objective is to enhance the safety and reliability of helicopter operations by modifying the hoist and ensuring proper electrical bonding, thus preventing uncommanded cable cuts during cargo winching while still prohibiting the pyrotechnic device for personnel winching until further investigation is complete.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the safety directives concerning the Eurocopter AS 355 (Twin Ecureuil) Series Helicopters, focusing on the installation of electric hoists. This legislative instrument applies to all AS 355 helicopters as outlined in the requirement document and mandates compliance with particular modifications and checks to ensure safety. The requirement stipulates that the hoist must be modified in accordance with paragraph 1 C 1 of Aerospatiale Service Bulletin 25-30 if not already done, and an Electrical Bonding Check must be carried out as per paragraph 1 C 3 of the same bulletin. Furthermore, the pyrotechnic cable cutting squib should not be re-installed, as specified by AD/SUPP/12. Compliance with these requirements must occur within 50 hours of time in service after 12 January 1992, but no later than 12 March 1992 for the modifications, and subsequently at intervals not exceeding 24 months or whenever the hoist or hoist arm is removed and reinstalled. The directive extends its reach to ensure the bonding between hoist components and the aircraft, reducing the risk of un-commanded cable cuts during cargo winching, while prohibiting the fitment of the pyrotechnic device for personnel winching pending further investigation.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105, contain the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives, including specific provisions for the Eurocopter AS 355 (Twin Ecureuil) series helicopters. This legislation mandates certain modifications and checks for the electric hoist installations on these aircraft. Section (1) requires that, if not already done, the hoist must be modified in accordance with paragraph 1 C 1 of Aerospatiale Service Bulletin 25-30. Additionally, an Electrical Bonding Check must be performed as per paragraph 1 C 3 of the same bulletin, ensuring that the bonding between the component parts of the hoist is adequate. This directive is critical to reducing the risk of uncommanded pyrotechnic cable cuts. The obligations under this legislation are quite specific. Operators of AS 355 helicopters must ensure that the modifications and checks are performed within the stipulated timeframes. For instance, the modifications must be completed within 50 hours of time in service after 12 January 1992, but no later than 12 March 1992. Furthermore, the Electrical Bonding Check must also be carried out within the same timeframe and then repeated at intervals not exceeding 24 months. These checks are mandatory whenever the hoist or the hoist arm is removed and reinstalled on the aircraft. There are important caveats within the requirements. Notably, the pyrotechnic cable cutting squib must not be reinstalled, as per AD/SUPP/12, which prohibits the use of this device for personnel winching pending further investigation. This prohibition ensures safety by preventing inadvertent firings of the pyrotechnic device that have occurred in the past. Additionally, while AD/SUPP/13 mandates modification and testing of the bonding between the component parts of the Air Equipment Hoist P/No 76370, the current directive ensures that the pyrotechnic device is only used for cargo winching. Failure to comply with the provisions set out in the Civil Aviation Regulations 1998 can result in serious consequences. While specific penalties are not detailed in the provided text, breaches of airworthiness directives generally carry significant civil or criminal penalties. Non-compliance can lead to enforcement actions by the Civil Aviation Safety Authority, which may include fines, suspension, or revocation of operating certificates. These measures underscore the importance of adhering to the requirements to ensure the continued airworthiness and safety of the aircraft.