The FAA has issued an emergency Airworthiness Directive (AD) to operators and owners of Boeing 737NGs to inspect the aircraft’s elevator tab control mechanisms following an incident on a Ryanair 737-800.
The FAA says the AD originated from a reported “failure of aft attach lugs on the left elevator tab control mechanism, which resulted in severe elevator vibration… Subsequent investigation revealed extensive damage to the elevator tab control system. Severe vibration in this attach point is suspected of allowing rapid wear of the joint, and resulted in failure of the attach lugs. This condition, if not corrected, could result in a loss of aircraft control and structural integrity.”
The AD came after Boeing issued an Alert Service Bulletin on March 12 which describes procedures for a detailed inspection to detect discrepancies of the inboard and outboard aft attach lugs of the elevator tab control mechanism, with 12 or 30 days to comply depending on the specific aircraft. The AD also requires reporting the inspection results to Boeing.
Both Qantas and Virgin Blue operate substantial fleets of 737NGs, but neither has said if they expect their schedules to be affected by the required inspections to their aircraft.