What was found
(CAN) DURING 100 HR INSP, FOUND CYLINDER NR 4 EXHAUST RISER BULGED AT COLLECTOR, BULGE IS CONSISTENT WITH DIRECTION OF CYLINDER NR 4 EXHAUST FLOW. UPON REMOVAL, NOTICED THE EXHAUST TO BE QUITE THIN AND APPEARED TO HAVE LOST MATERIAL. A GENTLE TAP WITH A SOFT FACED HAMMER EASILY COLLAPSED THE PIPE. ENGINE HAS INDIVIDUAL CHT, AND EGT PROBES SO AN OVER TEMP WOULD BE UNLIKELY. ENGINE CYLINDER NR 4 IS STILL SERVICEABLE, NO OTHER ISSUES FOUND.