THE APPLICATION OF A SEALANT INSTEAD OF A LUBRICANT TO THE INTERNAL 'O' RINGS SEALS IN THE FUEL SELECTOR BY MAINTENANCE PERSONNEL. FACTORS CONTRIBUTING TO THE ACCIDENT WERE THE PILOT'S INABILITY TO SELECT A FUEL SOURCE AND FUEL STARVATION THAT RESULTED IN AN ENGINE FAILURE. ROUGH TERRAIN AT THE LANDING SITE WAS ALSO A FACTOR IN THE ACCIDENT.