What was found
FLT JB78 - MCO-JFK "SLAT FAIL" AT ZERO DURING DESCENT FOR LANDING, SLATS SELECTED AND FAILED TO MOVE. CREW NOTIFIED ATC, AIRCRAFT LANDED SAFELY. MX TROUBLESHOT PER AMM FIM 27-81-00 FOUND RIGHT WING SLAT ACTUATOR NR 4 AT FAULT, REMOVED AND REPLACED RT WING NR 4 SLAT ACTUATOR IAW AMM 27-81-01, OPS CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.