As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AMS - FL 43 - AFTER TAKEOFF, CREW REPORTED THAT THE CAPTAINS ADI AND HSI WERE BLANK AND THE 'SG FAIL' WAS DISPLAYED. SELECTING ALTERNATE EFI CORRECTED THE FAULT. THE FLIGHT RETURNED TO AMS AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LEFT SIGNAL GENERATOR. (M)