As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT ENGINE OIL FILTER BYPASS LIGHT ILLUMINATED. BOTH THE DELTA "P" SWITCH AND THE FILTER WERE FORWARDED TO PWA FOR INVESTIGATION. THE SWITCH WAS FOUND TO BE TO BE WITHIN OPERATIONAL LIMITS. THE FILTER WAS SENT TO THE PWA LAB AND FOUND TO CONTAIN SUB MICRON CARBON PARTICLES, BUT IT WAS NOT 100% PLUGGED. AT THIS TIME IT IS BELIEVED THAT THE CARBON IN THE FILTER WAS THE ROOT CAUSE.