What was found
DURING CRUISE FLIGHT, NR 1 ENGINE CHIP LIGHT ILLUMINATED AND HEARD STRANGE NOISE. BROUGHT NR 1 ENGINE TO IDLE. AS NOISE INCREASED, SHUT ENGINE OFF. MADE UNEVENTFUL SINGLE ENGINE LANDING. MX FOUND THAT NR 1 ENGINE OIL FILTER BYPASS BUTTON HAD POPPED. CHIP DETECTOR WAS COVERED WITH METAL PARTICLES, AND THE POWER TURBINE DISK HAD MADE CONTACT WITH SHROUD AND ONE PT BLADE WAS MISSING. THE EXHAUST CASE STRUTS WERE CRACKED AND COVER WAS ALSO MISSING.