What was found
DURING FLIGHT OPERATING WITH MEL 24.00.01. APU SHUTDOWN INFLT. FL 350. RAN QRH & DECLARED AN EMERGENCY. DIVERTED. OPENED APU COWLINGS TO INVESTIGATE SOURCE OF OIL LEAK. SIGHT GLASS SHOWS NO OIL INDICATION SAME IN COCKPIT INDICATION. MASTER CHIP DETECTOR SHOWS HEAVY METAL CONTAMINATION. HAND CRANK ACCESS PORT AT APU STARTER HAS SOME SOME RESISTANCE. STILL EVALUATING SOURCE OF OIL LEAK. NO ODVIOUS EXTERNAL LRU COMPONENTS LEAKING. EVIDENCE OF LEAK BOTTOM OF APU HEAT SHIELD. RELEASED FOR SERVICE IAW MEL.