AD FAA-2010-0430

The FAA is superseding an existing airworthiness directive (AD) that applies to all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. The existing AD currently requires doing a detailed inspection of the inboard and outboard aft attach lugs of the left and right elevator control tab mechanisms for gaps between the swage ring and the aft attach lug, and between the spacer and the aft attach lug; trying to move or rotate the spacer using hand pressure; and replacing any discrepant elevator tab control mechanism, including performing the detailed inspection on the replacement part before and after installation. For certain airplanes, this new AD adds improved repetitive inspections for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator control tab mechanisms, and replacement if necessary. For certain other airplanes, this new AD adds a one-time inspection for discrepancies of the inboard and outboard aft attach lugs of the left and right elevator control tab mechanisms, and replacement if necessary. For airplanes on which the elevator control tab mechanism is replaced with a certain mechanism, this AD requires repetitive inspections for discrepancies of the elevator control tab mechanism and replacement if necessary. Replacing the elevator control tab mechanism with a new, Boeing-built mechanism terminates the repetitive inspections. This AD results from a report of failure of the aft attach lugs on the left elevator tab control mechanism, which resulted in severe elevator vibration; this event occurred on an airplane on which the existing AD had been done. We are issuing this AD to detect and correct a loose bearing in the aft lug of the elevator tab control mechanism, which could result in unwanted elevator and tab vibration. Consequent structural failure of the elevator or horizontal stabilizer could result in loss of structural integrity and aircraft control.