What was found
N416MC REQUESTED TO RETURN TO AMS TO TROUBLESHOOT DEFERRED APU BECAUSE OF SCHEDULE AND GROUND SUPPORT EQUIPMENT AVAILABLE AT RIX, OAI. FLIGHT OPERATION REQUEST.(<P>TROUBLESHOOTING CARRIED OUT PER FIM FOR CMC FAULT 49091. CHECKED INLET PLENUM FOR OBSTRUCTIONS FOUND. CHECKED CHIP DETECTORS. FOUND SATISFACTORY. REPLACED N1 SPEED SENSOR IAW AMM 49-61-02. REPLACED DIVERTER VALVE IAW AMM 49-52-04 (OFF PART: PN 3900430, SN F55969), REPLACED APU FUEL FILTER IAW AMM 49-31-00 (OFF PART: PN ACB881F25, NSN). APU OPS CHECK SATISFACTORY IAW AMM 49-11-00.</P>)