What was found
FLT # 316, SFO-JFK. STRONG ODOR IN COCKPIT DURING DESCENT. BEGAN AROUND 19,000 FEET. DISSIPATED BY 3,000 FEET. DID NOT DESCEND THROUGH ANY CLOUDS. NO ODOR DETECTED IN CABIN. ODOR WAS OF SOMETHING BURNT OR POSSIBLY "DIRTY SOCKS".; REF L/P 4559324-2, 4559325-1, 4559326-2, 4559323-1. LEVEL B DE-CONTAMINATION PERFORMED IAW AMM 21-00-00-615-803-A. NO ODOR DETECTED. A/C OK FOR SVC.REMOVED + INSPECTED APU COOLING FAN AND FOUND NO SIGNS OF OIL CONTAMINATION ON INLET + OUTLET. RE-INSTALLED APU COOLING FAN IAW AMM 49-52-51. OPS CHK OK. NO LEAKS NOTED.PERFORMED DECONTAMINATION OF THE BLEED-AIR DUCTING SYSTEM DISCONNECTED AT HP GROUND CONNECTOR WITH THE APU BLEED PRESSURE IAW AMM 36-12-00. PERFORMED LEVEL B REMOVAL OF THE CONTAMINATION OF THE ECS IAW AMM 21-00-00-615-803-A. NO ODOR DETECTED. REF L/P 4559324 ITEM 1 FOR PACK PANEL CLOSE-UP AND REF L/P 4559325 ITEM 2 FOR RECIP FAN FILTER REPLACEMENT.RE-INSTALLED LH+RH PACK CONDENSER SLEEVES IAW AMM 21-00-00-615-803-A SUBTASK 21-00-00-00-869-073-A.