19990315002489A

(-23) According to the pilot, while about 20 miles north of jefferson county airport, she switched the fuel selectors from the auxiliary tanks to the main tanks on both engines. Several minutes later, teh left engine began to lose power. Shortly thereafter, she was able to restart the left engine. When on a two mile final to runway 29R, the left enigne lost power again. Upon landing, the aircraft yawed to the left and departed the left side of the runway. The investigation is continuing. (.4) the airplane was north of the airport at 8,000 feet inbound for landing when she turned on the fuel boost pumps and switched from the auxiliary to the main tanks following a momentary surge. Minutes later, the left engine began to surge again. She was able to substantially restore power to the left engine. During approach to landing, the power on the left engine began to surge again, followed by a partial loss of power. As she flared for landing, the a/c veered to the elft and departed the runway into the grass. Based on the pilot's fuel calculations, the aircraft should have had 53.2 gallons of fuel remaining when she landed. The day after the accident, fuel was found in the right main fuel tank; however, the left tank was compromised and the presence of fuel could not be verified. Following the accident, the left engine was run in a test cell. The engine operated up to the maximum available power, and no discrepancies were observed. The turbocharger was also examined, and no abnormalities were found.