What was found
FLT 1199 JFK-ACK, AIR RETURN DUE TO SLAT FAIL ON RETRACT, RESET UNSATISFACTORY. FOUND ALL SLATS ON LT WING AND RT WING OUT OF RIG. MECHANICALLY RIGGED ALL SLATS ON LT AND RT WING IAW AMM 27-80-00-820-801-A. PERFORMED ELECTRONIC RIGGING OF ALL SLATS IAW AMM 27-80-00-820-802-A. SLAT RESOLVERS AND SKEW SENSORS WITHIN RIG LIMITS. OPS CHECK AND RIG CHECK OK.