What was found
ON LANDING DESCENT AT 37K, AS THROTTLES WENT TO IDLE, THE CABIN ALTITUDE HORN SOUNDED AT 10,000 FEET. CREW DECLARED AN EMERGENCY, DESCENDED RAPIDLY AND CABIN STAYED AT 10,000 FEET TILL LEVEL. MAINTENANCE FOUND APU BLEED DUCT RUBBER BOOT LOOSE. SECURED AND TESTED IAW AMM 05-51-91-790-801. PRESSURIZATION SATISFACTORY, ACFT RETURNED TO SERVICE.