As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LHR - FLT 66 - EN ROUTE LHR - APPROXIMATELY 20 MINUTES PRIOR TO LANDING A BURNING ELECTRICAL SMELL WAS NOTICED IN COCKPIT. LANDED WITHOUT INCIDENT. REPLACED AUTO FLIGHT MODE CONTROL SELECT PANEL AND CAPTAINS DME/VOR PANEL. ACCOMPLISHED MCDP TEST 40. INSPECTED WINDOW HEAT CONNECTIONS AND COOLING DUCTS. SYSTEM GROUND CHECKED NORMAL OPERATIONS. (M)