What was found
HAD AN ELECTRICAL BURNING ODOR IN THE COCKPIT. LASTED APPROX 20 MINS. APPEARED TO BE COMING FROM THE VENT BEHIND THE CAPT SEAT ON THE FLOOR. T/S WITH HEAVY ELECT/AVIONICS LOAD-NTF. INSPECTED E/E COMPT, NO EVIDENCE OF ABNML. CHECKED IFE/GALLEYS/OVENS/CM/LIGHTING/CHILLER NTF. CHECKED P5 OVERHEAD PANEL ALL GOOD. COULD NOT DUPLICATE. PER CREW COMMENT ODOR DISSIPATED WHEN AFT CARGO HEAT TURNED OFF. K228 RELAY REPLACED REF ITEM H500712001. ALL CHECKS GOOD.