1AD/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

 

Image unavailable in extracted text Bell Helicopter Textron 412 Series Helicopters

 

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

DM

 

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.