What was found
THE A/C DEPARTED SFA EN ROUTE TO LGA, WHEN THE LANDING GEAR WAS SELECTED UP THE LEFT MLG DID NOT RETRACT. THE A/C RETURNED TO SFA AND LANDED WITHOUT INCIDENT. AN EXAMINATION OF THE AFT TIMING VALVE REVEALED A SMALL CRACK IN THE STRIKER ARM, THIS ALLOWED THE LEFT MLG DOOR AFT TIMING VALVE TO GO OUT OF RIG. THE AIRCRAFT WAS FERRIED WITH THE GEAR DOWN TO A BASE WHERE THE ARM WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE. THE CRACK STARTED IN A HOLE DRILLED FOR SAFTY WIRE. THE CRACK IS ONLY .25 INCH LONG AND IS DIFFICULT TO SEE. (M)