What was found
AIRCRAFT WAS IN CRUISE AT FL 35000, WHEN CREW NOTICED THAT THE AIRCRAFT BEGAN TO GRADUALLY DEPRESSURIZE. THE CREW ELECTED TO DESCEND TO A LOWER ALTITUDE. DURING DESCENT CABIN PRESSURE DROP CAUSED THE AURAL WARNING HORN TO SOUND AND PAX OXYGEN MASKS TO DEPLOY. CREW THEN DECLARED AN EMERGENCY AND DIVERTED TO BUF INTERNATIONAL AIRCRAFT MADE NORMAL LANDING. AIRCRAFT WAS INSPECTED AND FOUND CLAMPS SECURING MAIN CABIN AIR SUPPLY TUBE FLEX COUPLINGS HAD LOOSENED CAUSING LEAKAGE AND SUBSEQUENT LOSS OF PRESSURIZATION SYSTEM EFFICIENCY. ALL COUPLINGS CLAMPS SECURED A ACCOMPLISHED SYSTEM TEST. CHECKED OK.