What was found
LEADING EDGE DISAGREE: RTF JFK - THE PROXIMITY SWITCH ELECTRONIC UNIT (PSEU) INITIATED FLAP/SLAT FAILURE PROTECTION SHUTDOWN AFTER SENSING AN ASYMMETRIC DIFFERENCE BETWEEN SLAT SENSORS 299, 287, AND 305. THE SUBJECT SENSORS WERE FOUND TO BE CONTAMINATED WITH EXCESSIVE GREASE AND DIRT. SUBJECT SENSORS WERE CLEANED AND OPERATIONALLY CHECKED PER MM, ALL OPS CHECKS NORMAL. FINAL BITE CHECK OF THE PSEU INDICATED NO FAULTS.