COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Robinson R22 Series Helicopters AD/R22/34 Suspect Bolts 5/92 DM Applicability: Model R22 with serial numbers 1880 through 2060, and 2073. Also any R22 which has been overhauled or repaired by RHC since 9 July 1991 and all R22 regardless of serial number for which maintenance was performed since 9 July 1991 in the locations where the suspect bolts may have been used. Requirement: Action in accordance with Robinson SB No 69. Note: FAA Telex AD 92-06-17 refers. Compliance: Within 10 hours time in service after 26 March 1992 or by 9 April 1992, whichever occurs first. Background: A Robinson Helicopter experienced a failure of an NAS1304-16 AF bolt installed in the tail rotor controls of an R22 helicopter. Examination indicated the bolt failed due to hydrogen embrittlement which occurred during cadmium plating. In-flight failure of this bolt could be catastrophic.