As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT, PILOT NOTICED A CHANGE IN SOUND. CONTINUED FLIGHT (7 MILES AWAY) TO DESTINATION. POST-FLIGHT INSPECTION REVEALED RT ENGINE COWL SIDE DOOR MISSING. COWLING HAD MADE MINOR CONTACT WITH ONE M/R BLADE. REF: BK-117 IPC, FIGURE 221, ITEM 10.