What was found
AT 0915 LOCAL TIME THEY WERE POSITIONED ON AIRPORT HOLDING, SHORT OF RUNWAY 19. NOTICED AIR CONDITIONING WAS NOT MAINTAINING & CABIN WAS GETTING WARM. AFTER CLEARANCE WAS GIVEN FOR TAKEOFF, POWER WAS APPLIED & THE ACFT BEGAN TO SHAKE, FELT LIKE A COMPRESSOR STALL. THE POWER WAS INSTANTLY PULLED BACK & THE VIBRATION WENT AWAY, WHEN POWER WAS APPLIED AGAIN IT STARTED TO SHAKE AGAIN. AT THE POINT THE ACFT BEHIND ADVISED THEM THERE WERE FLAMES COMING OUT THE NR 2 ENG. THE PIC CALLED FOR THE ENG FIRE CHECKLIST & PULLED THE T HANDLE. THE CREW INITIALLY FIRED THE NR 2 BOTTLE, 1ST SHOOT BUT DID NOT GET AN INDICATION THAT IT HAD GONE OFF. TAXIED ACROSS THE RUNWAY & WENT INTO THE HOLD AREA, RAN THE CHECKLIST AGAIN DURING WHICH WE HAD AN ORAL FIRE WARNING HORN & BLEW THE NR 2 ENG FIRE BOTTLE 2ND SHOOT AT THAT TIME. THE SECOND SHOOT DID GIVE THEM NOTIFICATION THAT IT HAD FIRED. CALLED FOR THE FIRE TRUCKS & THEY SHOWED UP, DID A VISUAL INSPECTION & GAVE THEM THE GREEN LIGHT TO RETURN TO THE GATE. THEY HAD THE FIRE & RESCUE FOLLOW FOR PRECAUTIONARY REASONS DUE TO PAX ON BOARD. WHEN THE VIBRATION HAPPENED PIC’S FIRST INDICATION ON THE ANNUNCIATOR PANEL WAS A FADAC 2 MALFUNCTION, FOLLOWED BY THE REMAINDER LIGHTS AFTER SHUTTING DOWN AN ENG. AGAIN THE LIGHT THAT THE PIC SAW WAS A FADAC 2 MALFUNCTION LIGHT. WHEN THE ENG WAS COMPRESSOR STALLING MY GAUGES FOR ITT & N2 WERE VERY ERRATIC. ACFT TAXIED TO THE GATE WITH NR 1 ENG LEAVING NR 2 ENG SHUTDOWN. AFTER RETURNING TO THE GATE & UNLOADING THE PAX, THE ACFT WAS VISUALLY INSPECTED. NOTICED SOME BLACK SOOT UNDERNEATH THE ENG FROM THE EVENTS & A STRONG ODOR OF ELEC BURNING. INSPECTED THE NR 2 ENG & FOUND THE OIL LEVEL GOOD & OIL LOOKED CLEAN. ENG GEN SHOWED NO DEFECTS & WOULD ROTATE BY HAND. WHEN ENG WAS ROTATED BY HAND WHEN COOL MX NOTICED CLUNKS & GRINDING AS THE ENG ROTATED. REPRESENTATIVE ON THE SCENE ELECTED TO REMOVE MOTOR & SEND IN FOR TEARDOWN. AWAITING TEARDOWN REPORT OF CAUSE.