COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Robinson R44 Series Helicopters AD/R44/8 Lateral Cyclic Trim Spring Shaft 4/98 TX Applicability: Model R44 helicopters, serial numbers 0002 through 0420, 0425, 0426, and 0427, with a C056-1 Rev. A through G spring assembly installed. Requirement: (a) Measure the diameter of the lateral cyclic trim spring shaft in accordance with the Compliance Procedure contained in Robinson Helicopter Company R44 Service Bulletin SB-26, dated 31 January 1998. (b) If the shaft diameter varies more than 0.004 inch in any 0.50 inch of length, in the measurement area shown in Figure 1 of SB-26, replace the C056-1 Rev. A through G spring assembly with a C056-1 Rev. H spring assembly before further flight. (c) Replacing the C056-1 Rev. A through G spring assembly with a C056-1 Rev. H spring assembly in accordance with above referenced service bulletin is considered terminating action for the requirements of this Directive. Note: FAA Priority Letter AD 98-04-12 refers. Compliance: Within 10 hours time in service after 13 February 1998, and thereafter at intervals not to exceed 25 hours time in service. This airworthiness directive becomes effective on 13 February 1998. Background: The FAA received a report of an incident in which a pilot felt binding in the cyclic control when attempting to move it to the left. A precautionary landing was made using only right-hand turns. Subsequent inspection revealed that a notch was worn in the lateral cyclic trim spring shaft, which caused the shaft and spring to move from the lower mount and interfere with the lateral control. Inspection of a second Model R44 helicopter revealed similar wear.