Commonwealth legislation

AD/BELL 412/13 - Tail Rotor Trunnion Bearing Housing

In ForceCTH

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

3/10 complexity

This AD requires owners/operators of Bell 412 helicopters S/N 33001–33118, 33120–33121 to follow Bell Alert Service Bulletin No. 412-86-25, Rev A: recurring inspections at the next and every 20‑hour check until a mandated Part II corrective action is done (within 150 flight hours or 60 days after 31 July 1986). It addresses an undersized trunnion bearing housing that can cause excessive tail‑rotor vibration and loss of control. Operators/maintenance providers must perform and pay for the inspections and repairs.

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Current sections

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AD/BELL 412/13 - Tail Rotor Trunnion Bearing Housing

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

View image in the official source Bell Helicopter Textron 412 Series Helicopters

AD/BELL 412/13 Tail Rotor Trunnion Bearing Housing 9/86

Applicability: All model 412 S/N 33001 to 33118, 33120 and 33121.

Requirement: Action in accordance with Bell Alert Service Bulletin No. 412-86-25, Revision A. Compliance: Part I: At the next 20 hour inspection and thereafter at each 20 hour inspection until

Part II is complied with.

Part II: Within 150 hours time in service or 60 days, whichever occurs first after 31 July 1986.

Background: A trunnion bearing housing end web has been found below specified dimensions.

Failure of the housing caused excessive tail rotor vibration and loss of control.

Source text

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