What was found
THE NR 2 PACK OVERHEATED ON APPROACH TO SPN AND THE NR 1 PACK OVERHEATED AFTER LANDING. THE OVERHEATING WAS ACCOMPANIED BY A STRONG BURNING ODOR ASSOCIATED WITH BOTH PACKS. THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE NR 1 AND NR 2 ACM'S FROZEN. THE NR 1 AND NR 2 ACM'S WERE REMOVED AND REPLACED. IN ADDITION, THE NR 2 PNEUMATIC CONTROLLER WAS REPLACED AS A PRECAUTIONARY MEASURE. LEAK AND OPERATIONAL CHECKS WERE GOOD.