What was found
DURING ROUTINE ENGINE WORK, FOUND THE NR 1 ENGINE HP BLEED AIR DUCT ASSEMBLY 90 DEG. CONNECTION WITH A BLOWN GASKET - BLACK SOOT EVIDENT ON THE BYPASS DUCT AND INNER SURFACE OF UPPER ENGINE COWL. THIS ENGINE IS SIMILAR AS THAT ON THE GULFSTREAM G150 AND THE EFFECTED PARTS IDENTICAL PER THE AIRCRAFT IPC'S. FOR THE G150, GULFSTREAM ISSUED SB 150-71-154 'POWERPLANT - ENGINE HIGH PRESSURE (HP) AIR DUCT ASSEMBLY SBJ10532-507 - MISMATCH'. THERE IS NO SUCH SB FOR THE GULFSTREAM G100/SPX AIRCRAFT.