The FAA is adopting an airworthiness directive (AD) for Bell Helicopter Textron Canada (Bell) Model 407s and 427s. It is based on a mandatory continuing airworthiness information (MCAI) AD issued by Transport Canada. The MCAI AD states that during a preflight check it was observed that the swashplate link assembly bearing had moved in the lever race, making contact with the swashplate support. Further investigation revealed that the bearing had not been staked correctly during manufacture. If not detected, the condition could result in the failure of a bearing, failure of the swashplate link assembly and subsequent loss of control of the helicopter. Bell has issued Alert Service Bulletin #407-09-87 for Model 407s and ASB #427-09-24, Revision A for Model 427s calling for a one-time inspection of all anti-drive link assemblies to ensure that the bearing is correctly and securely staked in the link assembly. The actions described in the MCAI AD are intended to correct the same unsafe condition as that identified in the ASBs. The AD becomes effective on November 16, 2009.
AD Targets Bell 407 and 427 Problem
- November 4, 2009, 10:34 AM