What was found
BURNING ODOR DURING FLIGHT, WITH PACK 1 ON. PERFORMED COOLING PACK SYSTEM TEST IAW AMM 21-51-00. RAN PACK 1 WITH APU BLEED, NO BURNING ODOR DETECTED, RAN PACK 1 WITH ENGINE BLEED 1 & 2. NO ODOR DETECTED. INSPECTED PACK 1 AREA WHILE PACK WAS RUNNING. NO DISCREPANCY NOTED. ACFT OK FOR SERVICE.