58-13-03 LOCKHEED: Applies to All Model 1649A Aircraft.
Compliance required as indicated.
Model 1649A aircraft have been found to have possible hazardous wing bending oscillation, dynamically induced by aileron oscillation, under certain combinations of boost package tolerances and autopilot modulating piston follow-up failure. In order to correct this condition, the following must be accomplished:
Modify the aileron control valve by installing a new modulating piston stop to meet limits of aileron deflection rates of 7.5 degrees per second minimum and 11 degrees per second maximum. The valve is then to be reidentified as 668152-11 and to be painted yellow to denote noninterchangeability with elevator and rudder valves. Details of the necessary modifications are given in Lockheed communication FS/225805-W, dated June 13, 1958.
This modification is to be accomplished as soon as maintenance schedules will permit but not later than January 1, 1959. Until the modification is accomplished, the airplane must be flown in autopilot operation at speeds not to exceed 215 KIAS.
This supersedes AD 58-11-04.