Commonwealth legislation

AD/R44/8 - Lateral Cyclic Trim Spring Shaft

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Commonwealth

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legislative instrument

Plain English Summary

3/10 complexity

This directive requires owners/operators of specified Robinson R44 helicopters (serial numbers 0002–0420, 0425–0427) fitted with C056‑1 Rev A–G lateral cyclic trim spring assemblies to measure the spring shaft diameter per Robinson Service Bulletin SB‑26 and, if variation exceeds 0.004 inch over any 0.50 inch, replace the assembly with Rev H before further flight (see Requirement (a)–(c)). It aims to prevent cyclic control binding from shaft wear; compliance creates inspection labour, measurement-tool needs and possible replacement costs, with replacement serving as terminating action.

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AD/R44/8 - Lateral Cyclic Trim Spring Shaft

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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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.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/R44/8 - Lateral Cyclic Trim Spring Shaft