COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Eurocopter AS 355 (Twin Ecureuil) Series Helicopters
AD/AS 355/39 Electric Hoist Installation 1/92
Applicability: All AS 355 helicopters as specified in the requirement document.
Requirement: 1. If not already incorporated, modify the hoist in accordance with paragraph 1 C 1 of Aerospatiale Service Bulletin 25-30.
2. Carry out an Electrical Bonding Check in accordance with paragraph 1 C 3 of Aerospatiale Service Bulletin 25-30.
Note 1: Do NOT re-install the pyrotechnic cable cutting squib in accordance with Aerospatiale SB 25-30. AD/SUPP/12 refers.
Note 2: DGAC AD 91-164-042(B) also refers. Note 3: AD/SUPP/13 also refers.
Compliance: Requirement 1. Within 50 hours time in service after 12 January 1992, but no later than 12 March 1992.
Requirement 2. Within 50 hours time in service after 12 January 1992, but no later than 12 March 1992, and thereafter at intervals not exceeding 24 months; and on each occasion following removal and reinstallation of the hoist or the hoist arm to the aircraft.
Background: A number of inadvertent firings of the pyrotechnic cable cutting device on a variety of helicopter electric hoists resulted in the removal of the pyrotechnic device from all hoists when used for personnel winching pending further investigation (AD/SUPP/12 refers). The pyrotechnic cable cut device is however still required to be fitted to hoists when hoisting cargo.
AD/SUPP/13 requires modification and testing of the bonding between the component parts of the Air Equipment Hoist P/No 76370 (all variants). Compliance with this AD (AD/AS 355/39) will improve the bonding between the hoist and the aircraft, and reduce the likelihood of un-commanded cable cuts when the pyrotechnic device is fitted for cargo winching. Note however that fitment of the pyrotechnic device for personnel winching is still prohibited by AD/SUPP/12 pending further investigation.