What was found
SMOKE IN CABIN AND EICAS MESSAGE OF SMOKE ON FLT DECK. SMOKE DETECTORS WENT OFF IN CABIN. DECLARED EMERGENCY. INITIAL INVESTIGATION SHOWS THAT THE APU SUFFERED VIBRATORY DISTRESS. THE COMPRESSOR HOUSING HAS A CRACK APPROXIMATELY 100 DEGREE LONG STARTING AT THE PLENUM ANTI-ROTATION TAB. FOUND LOWER INLET SCREEN HAS DISINTEGRATED. THE C1 SHOWS LIGHT FOD (FROM SCREEN). OIL FOUND IN BLEED DISCHARGE PIPES. T3 LOOKS FINE, THIS WOULD TEND TO ELIMINATE A T1 BLADE FAILURE AS THE CAUSE OF THE VIBRATIONS. APU DISASSY SHOWED NO AXIAL BEARING DISTRESS, HOWEVER THRUST WASHER SHIFT CAUSED SEAL FLR. SUSPECT INLET SCREEN FOD AS ROOT CAUSE.