Airworthiness Directives; Boeing Model 747SP Series Airplanes
We are adopting a new airworthiness directive (AD) for all Boeing Model 747SP series airplanes. This AD requires repetitive lubrication of the rudder tab hinges and repetitive replacement of the rudder tab control rods. This AD results from reports of freeplay- induced vibration on the control surfaces on Boeing Model 727, 737, 757, and 767 airplanes. We are issuing this AD to prevent damage to the control surface structure during flight, which could result in loss of control of the airplane.