What was found
(CAN) AFTER TAKEOFF THE LT ENGINE ENCOUNTERED RPM FLUCTUATIONS, THE AIRCRAFT RETURNED TO THE AIRPORT. AFTER SOME DISCUSSION WITH THE MECHANICS, THE PILOTS DRAINED THE AIRCRAFT AGAIN AND CARRIED OUT A GROUND RUN. EVERYTHING RETURNED TO NORMAL. THE AIRCRAFT DEPARTED RIGHT AFTER THE TANKS WERE FILLED. WHEN THE AIRCRAFT RETURNED TO BASE, WE VERIFIED AND CLEANED ALL THE INJECTORS AND DRAINED THE AIRCRAFT, ALL THE ENGINE FUEL LINES WERE PURGED AS WELL. THERE WAS NO WATER IN THE TANKS AND NO INJECTORS WERE CLOGGED.