NTSB Probable Cause

THE STUDENT PILOT'S INADVERTENT USE OF THE MIXTURE CONTROL INSTEAD OF THE COWL FLAPS AT A CRITICAL PHASE OF FLIGHT, HIS MISUSE OF THE FLIGHT CONTROLS AFTER THE ENGINE FAILURE AND THE INSTRUCTOR'S INADEQUATE SUPERVISION OF THE STUDENT. CONTRIBUTING FACTORS IN THE ACCIDENT WERE: THE NON STANDARD LOCATION OF THE COWL FLAP PUSH PULL CONTROL, DUE TO AN IMPROPER AIRCRAFT MODIFICATION, THE DARK NIGHT LIGHT CONDITIONS WHICH IMPAIRED THE FLIGHT INSTRUCTORS ABILITY TO MONITOR THE STUDENT COCKPIT CONTROL MANIPULATIONS.