What was found
AIRCRAFT RETURNED TO FIELD WHEN FUEL FILTER BYPASS LIGHT ILLUMINATED DURING CLIMB. INTERMITTENT ILLUMINATION OF THE FUEL BYPASS WARNING LIGHT INDICATING EXCESSIVE PRESSURE DIFFERENTIAL ACROSS THE FUEL FILTER WAS ATTRIBUTED TO A KINK IN THE FLEXIBLE PRESSURE LINES WHICH ARE LOCATED BETWEEN THE FUEL FILTER AND THE FUEL FILTER DIFFERENTIAL PRESSURE SWITCH. BOTH LINES HAVE BEEN REPLACED, ALONG WITH THE FUEL FILTER DIFFERENTIAL PRESSURE SWITCH AS PRECAUTIONARY. THE FUEL FILTER WAS ALSO CHECKED FOR CONTAMINATION AND REPLACED. THE NEW FILTER WAS SUBSEQUENTLY RECHECKED AFTER 24 HOURS AND NO CONTAMINATION FOUND.