AN INADEQUATE ENGINE COMPRESSOR CLEANING PROCEDURE SPECIFIED IN THE MANUFACTURER'S SERVICE LETTER, WHICH RESULTED IN THE TOTAL LOSS OF ENGINE POWER DUE TO CONTAMINATION, BLOCKAGE, AND COLLAPSE OF THE FUEL NOZZLE INLET SCREEN. FACTORS IN THE ACCIDENT WERE: THE LACK OF A SPECIFIED PERIODIC INSPECTION REQUIREMENT FOR THE NOZZLE SCREEN AND THE UNSUITABLE NATURE OF THE TERRAIN FOR THE FORCED LANDING.