As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, CREW NOTED LOW OIL PRESSURE INDICATION ON THE RT ENGINE. FOLLOWING THE CHECKLIST PROCEDURE, ENGINE WAS SHUTDOWN AND THE ACFT DIVERTED TO ANOTHER LANDING SITE. MX INSPECTION FOUND THAT THE OIL CAP WAS NOT INSTALLED ON THE OIL FILLER NECK.