What was found
DURING NIGHT/IMC CONDITIONS, AND WHILE BEING VECTORED FOR THE ILS FINAL APPROACH, THE LEFT BOOST PUMP LIGHT ILLUMINATED. CONFIRMED BOTH BOOST PUMP SWITCHES WERE ON, ENGAGED BOTH EMERGENCY BOOST PUMP SWITCHES. APPROXIMATELY 10 SECONDS LATER, THE ENGINE BEGAN TO SURGE. SENSING EITHER PENDING ENGINE FAILURE OR SIMPLE FUEL STARVATION, SWITCHED BOTH TANKS TO THE INBOARD POSITION. THE LEFT ENGINE CONTINUED TO SURGE, IT SEEMED ANY ATTEMPT TO RESTORE FUEL FLOW WOULD BE UNSUCCESSFUL, FOLLOWED SINGLE ENGINE FAILURE PROCEDURES, SECURED THE ENGINE, DECLARED AN EMERGENCY AND CONTINUED THE FINAL APPROACH TO A SUCCESSFUL SINGLE-ENGINE LANDING. ON INSPECTION, DEBRIS WAS FOUND IN THE METERING ORIFICE. CLEANING AND SUBSEQUENT ENGINE PERFORMANCE RUNS FOUND THE ENGINE OPERATION NORMAL AND THE AIRCRAFT RETURNED TO SERVICE.